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This is my page DO NOT EDIT!!! Carnivores (eats meat) are in red

Information on some Dinosaurs

Leptocycas was a cycad, a primitive seed plant from the late Triassic period. It was a palm-like tree with a long, woody trunk and tough leaves. It lived in warm climates. This tree was about 4.8 ft (1.5 m) tall. ||
 * Cycadophytes:**
 * [[image:http://www.enchantedlearning.com/lgifs/Leptocycas.GIF width="94" height="148"]]

//Williamsonia sewardiana// was a cycadeoid (a bennettitalean). It had a woody stem and simple leaves. || Cycadophytes included the Cycads and Cycadeoids (Bennettitales), plants with woody stems (some erect, some spherical) and very tough leaves. These two groups differ mainly in the way they reproduce: Cycads have separate male and female plants; Cycadeoids do not always. Cycadeoids are now extinct but there are still a few cycads. Some Mesozoic Era Cycads included: Leptocycas, Cycas, Zamia, Dioon, Bowenia, Stangeria, and Microcyas. Some Mesozoic Cycadeoids included: Cycadeoidea, Vardekloeftia, Williamsonia, Williamsoniella, Westersheimia, and Leguminanthus.
 * [[image:http://www.enchantedlearning.com/wgifs/Williamsonia.GIF width="96" height="143"]]

Cycadophytes dominated southern areas during the Triassic period and thrived during the Jurassic, but began to decline in the mid-Cretaceous period. Cycadeoids went extinct.

Gingkos (the maidenhair tree, family Gingkoaceae) are deciduous (losing their soft leaves in cold weather) gymnosperms that were common at higher altitudes. Gingkos peaked during the Jurassic and Cretaceous periods. Gingkos are still around today.
 * Gingkos:**

Horsetails were an important source of nutrition for plant-eating dinosaurs. These primitive vascular plants were fast-growing and resilient (they could propagate using underground runners which a grazing dinosaur wouldn't eat). This meant that a hungry dinosaur could eat the plant without killing it, since the plant would regrow from the rhizome (the underground stem). || Pteridophytes are a group of primitive vascular plants that include Lycopods (club mosses), [|Sphenopsids] (horsetails, shown left), and ferns (shown, right). These plants reproduce with spores that germinate only in moist areas; they also reproduce using rhizomes (underground stems). Pteridophytes evolved during the Devonian and were mostly low-growing during the [|Mesozoic Era]. These fast-growing, resilient plants were a source of food for [|plant-eating dinosaurs] that lived in moist areas.
 * Pteridophytes:**
 * [[image:http://www.enchantedlearning.com/hgifs/Horsetail.GIF width="44" height="134"]]

[|Glossopteris], a tree-like seed fern (Pteriosperm) from the Permian through the [|Triassic Period]. It had tongue-shaped leaves and was about 12 ft (3.7 m) tall. Glossopteris was a dominant plant in [|Gondwana] (the southern supercontinent) early in the Triassic period. || Seed ferns (Pteridosperms) had fern-like leaves but bore seeds and not spores. This group included Glossopteris, Dicroidium, Caytonia, Denkania, and Lidgettonia.
 * [[image:http://www.enchantedlearning.com/ggifs/Glossopteris.GIF width="94" height="187"]]
 * Seed ferns:**

Seed ferns dominated southern Pangaea during the Triassic period. Seed ferns went extinct during early in the Cretaceous period. Glossopterids went extinct at the end of the Triassic period.

Flowering plants (angiosperms) evolved about 140 million years ago, during the late [|Jurassic period] and dramatically changed the Earth's landscape, quickly taking over most of the ecological niches. These fast-growing, adaptable plants also gave rise to a HUGE boom in the dinosaur world. Most of the dinosaurs that have been found date from the late Cretaceous period, when flowering plants were suppling plant-eating dinosaurs (like hadrosaurs) with plentiful and nutritious food. Some Mesozoic Era angiosperms included magnolias, laurel, barberry, early sycamores, and palms. Grasses may have evolved later.
 * Flowering plants:**

**THE EVOLUTION OF LAND PLANTS**

**PANGAEA AND WEATHER DURING THE MESOZOIC ERA** The dinosaurs evolved early in the [|Mesozoic Era], during the Triassic period (about 228 million years ago). At the start of the Mesozoic Era, the continents of the Earth were jammed together into the supercontinent of Pangaea; this land mass had a hot, dry interior with many deserts. The polar regions were moist and temperate. During the Mesozoic, Pangaea began breaking apart and the weather changed.

​

**__List of some Australian Dinosaurs__**
 * //[|Agrosaurus macgillivrayi]// - a //[|nomen dubium]// or [|junior synonym] of //[|Thecodontosaurus antiquus]//. ([|Prosauropoda])
 * "[|Allosaurus]" sp.([|Theropoda]; probably represents a [|basal] [|allosauroid] like //[|Fukuiraptor]//, not //Allosaurus//)[|[1]]
 * //[|Atlascopcosaurus loadsi]// ([|Ornithopoda])
 * //[|Austrosaurus mckillopi]// ([|Sauropoda])
 * //[|Austrosaurus]// sp. ([|Sauropoda]) (Elliot and Mary)
 * //[|Fulgurotherium australe]// ([|Ornithopoda])
 * //[|Kakuru kujani]// ([|Theropoda])
 * //[|Leaellynasaura amicagraphica]// ([|Ornithopoda])
 * //[|Minmi paravertebra]// ([|Ankylosauria])
 * //[|Muttaburrasaurus langdoni]// ([|Ornithopoda])
 * //[|Ozraptor subutaii]// ([|Theropoda])
 * //[|Qantassaurus intrepidus]// ([|Ornithopoda])
 * //[|Rapator ornitholestoides]// ([|Theropoda])
 * //[|Rhoetosaurus brownei]// ("Rhaetosaurus", "Rheteosaurus") ([|Sauropoda])
 * //[|Serendipaceratops arthurclarkei]// ([|Ceratopsia])
 * //[|Timimus hermani]// ([|Theropoda])
 * //[|Walgettosuchus woodwardi]// ([|Theropoda])

[|**http://www.youtube.com/watch?v=_hQm9sLhdbM**] [|**http://www.youtube.com/watch?v=xNOnIrAvvS4**]
 * __Videos about dinosaurs__**

__**Dinosaur Questions to think about**__
 * 1) **What was the biggest dinosaur and wich period did it live?**
 * 2) **Wich dinosaur was the smallest of all?**
 * 3) **What kind of habitat did the dinosaurs live?**
 * 4) **Which dinosaur was the largest meat-eater?**
 * 5) **What is the first dinosaur ever found?**
 * 6) **Were there more plant-eaters or meat-eaters?**
 * 7) **What is the oldest dinosaur ever found?**
 * 8) **How many teeth did the T.rex have (and how big were they)?**
 * 9) **How are dinosaurs named?**
 * 10) **How (and when) did the dinosaur extinct?**



Name's meaning: Tyrant Lizard King
 * __T.rex information__

Pronounciation: tie-RAN-o-SAWR-us rex

Physical Description: Tyrannosaurus rex had two legs and was 40 feet long. It's jaws were up to 4 feet long and it's teeth grew up to be 13 inches long. Tyrannosaurus rex had bumpy skin like a crocodile. Some scientists think T. Rex could go up to 15 MPH. The T-REX weighed 5-7 tons. It's arms were 3 feet long. T. Rex had a stride length of around 12 to 15 feet.

Young Earth Age: Alive sometime in the last 6000 years.

Old Earth Age: According to old earth scientists, T-Rex lived in the Cretacious Period, about 85-65 million years ago.

Diet: It was a carnivore (meat eating dinosaur).

Fossil locations: T-Rex fossils have been found in north west America.

Classification: tetanurans. **

=ANKYLOSAURUS (Ankylosaurus magniventris)=




 * Name's meaning: "Fused, stiff, or bent Lizard"

Pronounciation: an-Kie-low-Saw-rus

Physical Description: A full grown Ankylosaurus measured about 25-35 feet long, 6 feet wide and 4-5 feet tall. It weighed between 3-4 tons (weight estimates vary greatly for dinosaurs). It was covered with a thick armor (oval shaped plates that were ingrained into it's skin). The armor covered the head, neck, back, tail and even it's eyes. Only it's belly was unprotected by it's armor. It had spikes around its body, and long horns that came out from the back of the head. It's tail looked like a giant club and could be used to attack other dinosaurs. Ankylosaurus had four short legs. The back legs were larger than the front legs.

Young Earth Age: Alive sometime in the last 6000 years.

Old Earth Age: According to old earth scientists, Ankylosaurus lived in the late Cretaceous Period, about 70-65 million years ago.

Diet: It was a herbivore (plant eating dinosaur).

Fossil locations: Ankylosaurus fossils have been found in the western USA (Montana, Wyoming) and Canada (Alberta).

Classification: Ankylosauridae**

=Triceratops (Triceratops horridus)=




 * Name's meaning: "Three Horned Face"

Pronounciation: tri-ser-a-tops

Physical Description: A full grown Triceratops measured about about 30 feet long, 10 feet tall (3 m), and weighed about 6-12 tons (weight estimates vary greatly for dinosaurs). It was about twice the size of a rhinoceros. It had four short legs with three horns on it's face. Two long horns were above it's eyes and one short stubby horn on it's nose. It had flat teeth and a thrill on it's head that protected it's neck. It also had a large tail.

Young Earth Age: Alive sometime in the last 6000 years.

Old Earth Age: According to old earth scientists, Triceratops lived in the late Cretaceous Period, about 65-72 million years ago.

Diet: It was a herbivore (plant eating dinosaur).

Fossil locations: Ankylosaurus fossils have been found in the Wyoming, Montana, South Dakota, Colorado, and Canada (Alberta, Saskatchewan).

Classification: Ceratopsia**

=Brachiosaurus=




 * Name's meaning: "arm lizard"

Pronounciation: BRAK-ee-oh-sore-us

Physical Description: A full grown Brachiosaurus measured about 100 feet long, and grew to between 40-50 feet tall. It weighed around 50-80 tons (weight estimates vary greatly for dinosaurs). The Brachiosaurus was a huge dinosaur, with long legs and a really long neck. Brachiosaurus had four long legs, it's front legs were longer than it's rear legs. The Brachiosaurus had really long nostrils on the top of it's head.

Young Earth Age: Alive sometime in the last 6000 years.

Old Earth Age: According to old earth scientists, Brachiosaurus lived in the Late Jurassic Period about 150 million years ago.

Diet: It was a herbivore (ate plants).

Fossil locations: Brachiosaurus fossils have been found in various locations in Africa and North America.

Classification: B.Altithorax**

=Oviraptor=

Name's meaning: "Egg stealer"

Pronounciation: O-vi-rap-tor

Physical Description: A full grown Oviraptor measured about 7 feet long, and weighed about 55-76 pounds(weight estimates vary greatly for dinosaurs). It had long legs, was fast, and walked on two legs. The Oviraprot had an S-shaped neck, a long tail, and curved claws. It had a parrot-like beak, and a horn like crest.

Young Earth Age: Alive sometime in the last 6000 years.

Old Earth Age: According to old earth scientists, Oviraptor lived in the Cretaceous period, about 88-70 million years ago.

Diet: It was omnivorous (plant and meat eater).

Fossil locations: Oviraptor fossils have been found in Mongolia.

Classification: Saurischia Connor's Attribute Listing
 * **[[image:http://www.enchantedlearning.com/cgifs/Cycad.GIF width="43" height="62" link="http://www.enchantedlearning.com/subjects/dinosaurs/plants/"]]

[|PALEOBOTANY]** Paleobotany is the branch of botany that studies the [|plants] that existed in former [|geologic periods], chiefly by studying fossils. || **

PALEONTOLOGY** Paleontology is the branch of biology that studies the forms of life that existed in former geologic periods, chiefly by studying fossils. "Paleo" means old or ancient. "Ontology" is the study of existence ("onto-" means existence, "-logy" is the study of something). || **

[|PALEONTOLOGIST]** A paleontologist is a scientist who studies paleontology, the forms of life that existed in former geologic periods, chiefly by studying fossils. "Paleo" means old or ancient. "Ontology" is the study of existence ("onto-" means existence, "-logy" is the study of something). This "-ist" at the end means a person who is involved in the field. ||

The Paleozoic Era (540 to 248 million years ago) saw an explosion of new life forms. The Paleozoic (meaning "ancient life") ended with the largest mass extinction in [|geologic history] and was followed by the [|Mesozoic Era]. It is divided into the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian periods. It was followed by the [|Mesozoic Era], the time of the dinosaurs. || The palisade [|parenchyma] (also called the palisade layer) is a layer of tightly-packed, tube-shaped, chlorophyll-containing cells (chlorenchyma) that is the major photosynthetic layer of a leaf. The palisade layer is located in the upper [|mesophyll] of a leaf (just beneath the upper dermal layer of the leaf). || A palm is an evergreen tree and a monocot. Classification: Division Magnoliophyta (Angioperms), Class Liliopsida (Monocots), Subclass Arecidae, Order Arecales, Family Arecaceae (or Palmae) (Palms). ||
 * **[|PALEOZOIC ERA]**
 * PALISADE PARENCHYMA**
 * PALM**

PALMATE** A palmate leaf has a hand-like structure. It has more than three lobes that branch from a single point at the base of the [|leaf]. || ** PALMATE VENATION** A [|leaf] with palmate venation has the main [|veins] arising from a point at the base of the leaf. || ** [|PANGAEA]** (pronounced pan-GEE-ah) Pangaea was a supercontinent consisting of all of [|Earth's] land masses. It existed during the Permian through the [|Jurassic period]. It began breaking up during the Jurassic, forming the continents [|Gondwanaland] and [|Laurasia]. ||
 * **[[image:http://www.enchantedlearning.com/subjects/plants/gifs/Palmatelycompndlf.GIF width="165" height="152"]]

[|PANTHALASSA]** (pronounced pan-tha-LASS-ah) Panthalassa (meaning "All seas") was the super-ocean that existed on Earth during the time of the super-continent Pangaea. Panthalassa existed during the Permian through the [|Jurassic period], when Pangaea began to break up; the Tethys sea formed between the northern and southern parts of pangaea as they drifted apart. || **
 * **[[image:http://www.enchantedlearning.com/pgifs/Pangaeaanim.gif width="157" height="78" caption="Pangaea" link="http://www.enchantedlearning.com/subjects/dinosaurs/glossary/Contdrift.shtml"]]

PARAPHYLETIC** A paraphyletic group (also called a grade) consists of a common ancestor and some, but not all, of its descendants. These are incomplete groups based primarily on physical characteristics rather than directly on evolutionary relationships. An example of a paraphyletic group is the dinosaurs (without including the birds). || ** PARALLEL VENATION** A [|leaf] with parallel venation (also called longitudinal-striate venation) has its [|veins] arranged almost parallel to one another. ||

A parasite is an organism which uses its host for food and/or shelter. A parasite gives its host nothing in return, and often makes it sick or even kills the host. Termites are a parasite of many trees. || Parasitism is arelationship between two organisms in which one organism benefits at the other organism's expense. Lice are an example of a parasite that affects many animals; termites are a parasite that are destructive to many trees. Parasitism is a type of [|symbiosis]. || Parenchyma are generalized (undifferentiated) cell or tissue in a [|plant]. Parenchyma cells make or store food; they can often divide or differentiate into different types of cells and have thin cell walls. Parenchyma is the most common type of plant cell. The [|pith] is parenchyma cells at the center of the primary stem of a dicot. ||
 * 
 * PARASITE**
 * PARASITISM**
 * PARENCHYMA**

Parsimony is the scientific idea that the simplest explanation of a phenomenon is the best one. ||
 * 
 * PARSIMONY**

**PARTED** A parted (also called cleft) [|leaf] is one in which the margins between the irregular teeth go more than halfway to the midrib. || ** [|PEANUT PLANT]** The peanut plant (//Arachis hypogea//) is a legume that is native to South America (it now grows around the world). The peanut plant grow to about about 60 cm tall and has yellow flowers (1-2 cm long). The flower blooms for about half a day. About 4 days later, a stem (also called a peg) will grow from the flower and head into the [|soil]. At the end of each stem, the seed pods (peanuts in the shell) will grow. The peanut is an annual plant (it completes its life cycle in one year). ||

Peat is a type of soil that is composed of incompletely decomposed [|plant] material that water-logged and low in oxygen. || A pedicel is plant stalk that attaches a single [|flower] or fruit to the main branch of the [|inflorescence]. ||
 * 
 * PEAT**
 * PEDICEL**

Pedogenesis is the natural process in which [|soil] forms. || ** PEDUNCLE** A peduncle is plant stalk that bears an [|inflorescence] or single [|flower]. || The Pennsylvanian Period lasted from 325 to 280 million years ago. During this time, the first reptiles (like Hylonomus) appeared and [|ferns] dominated the warm, swampy landscape. ||
 * 
 * PEDOGENESIS**
 * PENNSYLVANIAN PERIOD**

A [|plant] that perennates lives from year to year (it is a perennial). || A perennial [|plant] has a life cycle that lives for more than two years. Perennials usually [|flower] each year. || **
 * 
 * PERENNATE**
 * PERENNIAL**

PERFECT FLOWER** A perfect [|flower] has both male ([|stamen]) and female ([|ovary]) reproductive organs on the same flower. (Compare with [|imperfect flowers].) ||

The perianth (which means "around the anthers") is the [|sepals] and [|petals] of a flower. || The pericarp is the fruit wall that develops from the [|ovary] wall. The pericarp is divided into the endocarp, mesocarp and exocarp. ||
 * 
 * PERIANTH**
 * PERICARP**

The pericarpal is the upper part of the flower stem, the receptable, and the lower part of the pistil. || **[|PERIOD]** The period is the basic unit of geological time in which a single type of rock system is formed, lasting tens of millions of years. ||
 * 
 * PERICARPAL**

The Permian extinction was the largest mass extinction that ever occurred on Earth, but its causes are unknown. It occurred at end of the Permian period, about 248 million years ago. It in, trilobites went extinct, as did 50% of all animal families, 95% of all marine species, and many trees. Groups that went extinct included: the fusulinid foraminifera, trilobites, rugose and tabulate corals, blastoids, acanthodians, placoderms, and [|pelycosaurs] (like [|Dimetrodon]). Groups that were substantially affected included: bryozoans, brachiopods, ammonoids, sharks, bony fish, crinoids, eurypterids, ostracodes, and echinoderms. This extinction was followed by the [|Triassic period] of the [|Mesozoic Era]. || ** [|PERMIAN PERIOD]** The Permian period (named after the Perm Province in northeast Russia where rocks from this period were first described) is known as "The Age of Amphibians" (280 to 248 million years ago), this is when Pangaea formed and Earth's atmosphere was oxygenated to modern levels. In the early Pemian, labyrinthodonts dominated the land. The Permian ended with the largest mass extinction and was followed by the [|Mesozoic Era]. ||
 * **PERMIAN EXTINCTION**

Permineralization is the process in which minerals are deposited into a bony fossil. || ** PETAL** A petal is one of the leafy structures that comprise a [|flower]. Petals are often brightly-colored and have many different shapes. They are located between the [|sepals] and the flower's reproductive organs. ||
 * 
 * PERMINERALIZATION**

Petiolate means having a petiole. || **
 * 
 * PETIOLATE**

PETIOLE** A petiole is a [|leaf] stalk. On a [|compound leaf], the petiole extends from the [|stem] to the first set of [|leaflets]. A leaf without a petiole is [|sessile]. ||

Petrification is the process in which an organic tissue turns to stone. The original materials are repaced by minerals. || **
 * **PETRIFICATION**

PETRIFIED WOOD** Petrified wood is fossilized wood. Minerals seeped into buried logs, replacing the original tissues with rock. || [|**PHANEROZOIC EON**] The Phanerozoic (meaning "visible life") is the time in which life forms with skeletons or hard shells existed. It is the period from about 540 million years ago until the present. ||

Phenetics is a method of attempting to classify biological organisms that does not use genetic or evolutionary information; it was invented by Sokal and Sneath in 1963. In a phenogram, organisms are grouped by superficial overall similarity. Phenetics was abandoned by most scientists in the 1980's because its classifications were arbitrary, mostly useless, and unstable. Paul Ehrlich was a proponent of this system. || Phloem is [|plant] tissue that conducts nutrients (food) through the plant. In woody-stemmed plants, the phloem is the inner layer of the [|bark]. (Compare with [|xylem].) || (pronounced Pho-ma) Phoma is a genus of fungus that lives on a wide variety of plants (including sunflower, cabbage, banana, etc.). Phoma is characterized by large, black lesions on the stem and/or leaves of the infected plant. About 80 species of phoma have been described. ||
 * 
 * PHENETICS**
 * PHLOEM**
 * PHOMA**

Photosynthesis is the process in which [|plants] convert sunlight, water, and [|carbon dioxide] into food (sugars and starches), oxygen and water. [|Chlorophyll] or closely-related pigments (substances that color the plant) are essential to the photosynthetic process. || Phototropism is the bending of a [|plant] in response to sunlight. This reaction is caused by the growth hormone [|auxin] that is contained in the [|stem]. || A phylloclade is a flattened stem that looks like a leaf. ||
 * 
 * PHOTOSYNTHESIS**
 * PHOTOTROPISM**
 * PHYLLOCLADE**

A phyllode is a leaf that has an enlarged midrib and no blades. || Phylogeny is the evolutionary relationship between organisms. The phylogeny of an organism reflects the evolutionary branch that led up to the organism. || **[|PHYLUM]** (plural plyla) In classification, a phylum is a group of related or similar organisms. A phylum contains one or more classes. A group of similar phyla forms a Kingdom. The [|plant] phyla include: Ginkgophyta, Lycophyta (lower ferns like clubmosses), Pterophyta (ferns), Psilophyta (whisk ferns), [|Anthophyta] (flowering plants), Gnetophyta, Sphenophyta, Coniferophyta (conifers), Cycadophyta (cycads), Sphenophyta, and [|Bryophyta] (mosses, liverworts, hornworts). ||
 * 
 * PHYLLODE**
 * PHYLOGENY**

PINNATE COMPOUND LEAF** A pinnate compound leaf is made up of many small [|leaflets] arranged in pairs on either side of a long central [|midrib] (the [|rachis]). There is often a single terminal leaflet at the end of the midrib. || ** PINNATELY LOBED LEAF** Pinnately lobed [|leaves] have many lobes arranged along the [|midrib]. || ** PINNATE VENATION** A leaf with pinnate venation has its [|veins] arranged in pairs coming from a main central [|midrib] vein (the [|rachis]). ||
 * **[[image:http://www.enchantedlearning.com/subjects/plants/gifs/Pinnatecompndlf.GIF width="140" height="146"]]

A pioneer is a [|plant] that is the first (or among the first) to live in a new area. || ** PISTIL** The pistil is the central set of female reproductive organs in a [|flower]. The pistil is composed of one or more [|carpels] and produces the [|ovule]. || Pistillate [|flowers] have a pistil or pistils. ||
 * 
 * PIONEER**
 * PISTILLATE**

The pith is [|parenchyma] cells at the center of the primary stem of a [|dicot]. || **PLANT** A [|plant] is a member of the kingdom Plantae, a living organism that undergoes [|photosynthesis]. || Plantae is a kingdom in the classificaton of life on Earth. Plantae ([|plants]) is divided into non-vascular plants, vascular plants, and seed plants. ||
 * 
 * PITH**
 * PLANTAE**

Plant succession is the natural pattern of ecosystem growth and change over time for a particular environment. Plant life follows established patterns of growth and change after major distruptions, like fires, floods, agricultural damage, logging, etc. Generally, smaller, fast-growing herbaceous species and grasses grow first in an open field, followed in a few years by softwood tree seedlings and larger herbaceous species. As a young forest develops into a mature forest (30 to 70 years), an understory of smaller hardwood trees develops. The final stage is a climax hardwood forest (100 plus years). || A plasma membrane (also called the cell membrane or plasmalemma) surrounds each cell and separates it from the environment. In pants, the cell membrane contains cellulose (a carbohydrate). || A plasmalemma (also called the cell membrane or plasma membrane) surrounds each cell and separates it from the environment. In pants, the cell membrane contains cellulose (a carbohydrate). ||
 * 
 * PLANT SUCCESSION**
 * PLASMA MEMBRANE**
 * PLASMALEMMA**

A plasmid is a circular loop of DNA found in prokaryotic cells (like those of bacteria). [|Eukaryotic cells] prokaryotic cells (like plant and animal cells) do not have plasmids, they have chromosomes. || ** Forward Backward [|PLATE TECTONICS]** Plate tectonics is the now-established theory that [|chunks] of the [|Earth's crust] (plates) float on the surface and change both position and size over time. ||
 * **PLASMID**

Platysperms (meaning "flat seeds") are [|plants] with flattened ovules. Platysperms include [|gingkos], [|conifers], [|glossopterids], and cordaites. || The Pleistocene was an epoch of geologic time that lasted from 1.8 million to 11,000 years ago; it was a period of widespread glaciation and large Ice Age animals (caled Pleistocene Megafauna). The first humans (Homo sapiens) evolved during the Pleistocene. Mammoths, mastodons, [|saber-toothed cats], giant ground sloths, and other [|Ice Age mammals] evolved. A mass extinction of large mammals and many birds occurred about 10,000 years ago, probably caused by [|Ice Ages]. ||
 * 
 * PLATYSPERMS**
 * PLEISTOCENE**

Plesiomorphy (meaning "old form") is a primitive character of a group. ||
 * PLESIOMORPHY**

The plumule is the shoot of a [|plant] [|embryo] (in the seed before germination). || A pneumatophore is an air-transporting vessel in plants. || A seed pod is an elongated, two-sided vessel that contain several fertilized seeds. It is a [|dehiscent fruit] or [|pedicarp] - the pod splits open when the seeds are mature. Beans and peas are some plants that have pods. ||
 * **PLUMULE**
 * PNEUMATOPHORE**
 * POD**

Podzol is a kind of [|soil] that is very low in [|humus]. || Pollen is the male reproductive cell of flowering [|plants] and cone-bearing plants. Pollen [|grains] are produced in the [|anther] of a [|flower]. || Pollination is the transfer of pollen from the [|anther] to the [|stigma]. ||
 * 
 * PODZOL**
 * POLLEN**
 * POLLENATION**


 * **[[image:http://www.enchantedlearning.com/subjects/plants/gifs/Floweranatomy.GIF width="248" height="158" link="@http://www.enchantedlearning.com/subjects/plants/printouts/floweranatomy.shtml"]]

POLLEN TUBE** After the male's [|pollen] grains have landed on the stigma during fertilization, pollen tubes develop within the style. The pollen tubes transport the sperm from the grain to the ovum (where fertilization of the egg occurs and the seeds will develop). || **

POLYPHYLETIC** A polyphyletic group consists of organisms but not their common ancestors. This is an artificial group which is based primarily on physical characteristics rather than on evolutionary relationships. An example is "flying vertebrates" which includes birds, [|pteranodons] and bats. ||

Pollination is the process in which the male's pollen fertilizes the female's [|ovule] and creates a [|seed]; the [|pollen] is transferred from the male's [|anther] to the female's [|stigma]. Pollination is effected by the wind, insects, hummingbirds, etc. || A pollinium (or pollinia) is a mass of fused pollen grains that is produces by a single [|anther]. This mass sticks together and during pollination is transported as a single unit. Orchids have polliniums. ||
 * 
 * POLLINATION**
 * POLLINIUM**

The Precambrian is the time 540 before the Cambrian period (before million years ago). It is the time from when the Earth formed until simple life-forms evolved. || **PREHISTORIC** Prehistoric refers to the time before people began recording history in writing. This time varies from culture to culture. || An animal becomes prey when another animal hunts and kills it for food. Insects are the prey of the Venus fly trap. ||
 * 
 * PRECAMBRIAN**
 * PREY**

A prickle is a a sharp outgrowth of a plant's epidermis (outer skin). Prickles are easily broken off a plant. Roses have prickles. || ** PRICKLY PEAR CACTUS** Prickly pear cacti (genus Opuntia, many species) are North American desert succulents that have flat, fleshy, leaf-shaped pads and large spines (modified leaves) growing from tubercles (small bumps on the pads). They have red, yellow, or purple flowers. Prickly pear cacti and their fruit are edible. || The primary root is the first [|root] of a [|plant] to develop in the germinating seed. The primary root develops from the [|radicle] of the [|embryo]. It is also called the taproot ||
 * 
 * PRICKLE**
 * PRIMARY ROOT**

Primary vegetation is the [|plants] life that has been in place since the area reached its [|climax] state. || ** PRIMARY CONSUMER** A primary consumer is an herbivore (a plant-eater). Primary consumers occupy the second trophic level in the grazing food chain. ||
 * 
 * PRIMARY VEGETATION**

A primary forest is a [|forest] that has never been logged or disturbed. || Primary growth is [|plant] growth that occurs at the tips ([|terminal bud]) of the stem or the tip of the [|roots], at the [|apical meristems]. In seed plants, primary growth produces. || ** PRODUCER** A producer (or aurotroph) is an organism that makes its own food from light energy (using photosynthesis), or chemical energy (using chemosynthesis). Most green [|plants], many protists (one-celled organisms like slime molds) and most bacteria are producers. Producers are the base of the food chain. ||
 * 
 * PRIMARY FOREST**
 * PRIMARY GROWTH**

A protoplast is a [|plant] or bacterial cell whose cell wall has been removed. || **PROTOZOA** Protozoans (meaning "first animals") are a phylum of primitive animals that include the following classes: Mastigophora (flagellates), Sarcodina (amoebas), Sporozoa (Parasites), and Ciliata (Ciliates). || **PSAMMOPHILE** A psammophile (meaning "sand loving") is a plant that lives in sand or sandy [|soils]. Some psammophytic plants include //Salix psammophila// (a willow), //Dypsis psammophila// (a palm) and //Cocolobo diversifolia// (the pigeon plum). ||
 * 
 * PROTOPLAST**

Psilophyta are a division of primitive [|plants] that are also called wisk ferns (they are not true ferns). Psilophytes are seedless vascular plants with underground rhizomes. They live in tropical to sub-tropical areas and are terrestrial or [|epiphytic]. There are only 2 genera (Psilotum and Tmesipteri), and only a few living species. || **PTERIDOPHYTES** Pteridophytes are a group of primitive vascular [|plants] that include Lycopods (club mosses), [|Sphenopsids] (horsetails, shown left), and ferns (shown, right). These plants reproduce with spores that germinate only in moist areas; they also reproduce using rhizomes (underground stems). Pteridophytes evolved during the Devonian and were mostly low-growing during the [|Mesozoic Era]. These fast-growing, resilient plants were a source of food for [|plant-eating dinosaurs] that lived in moist areas. ||
 * **PSILOPHYTA**

PTERIDOSPERMS** Pteridosperms (Seed ferns) were [|primitive seed plants] (not ferns at all) that lived in swampy areas from the Mississipian Epoch through the [|Mesozoic Era]. They had woody stems studded with dried out leaf bases. The tops had fern-like fronds which bore seeds. Some seed ferns include Glossopteris (pictured above), Dicroidium, Caytonia, Denkania, and Lidgettonia || **Jurassic Plants**
 * **[[image:http://www.enchantedlearning.com/ggifs/Glossopteris.GIF width="94" height="187"]]

The [|Jurassic period] (206-144 million year ago) was the time when the enormous [|sauropods] (like [|Brachiosaurus], [|Diplodocus], and [|Apatosaurus]) lived, devouring tremendous amounts of foliage each day, probably mainly conifers. There probably weren't many of these gigantic plant-eaters in any one area since competition for food would have been a problem. These sauropods may have destroyed forests and trampled other plant habitats, forcing these dinosaurs to migrate occasionally in order to find new food sources.

[|Conifers] (like Araucarioxylon) were the dominant land plant during the Jurassic period. Other land plants included Ginkgophytes (like [|Ginkgos]), [|club mosses], horsetails, [|ferns], [|seed ferns], Sphenopsids (like Neocalamites), Filincophyta (like Matonidium), Cycadeodia (like Otozamites, Ptilophyllum, and Cycadeoidea), and [|cycadophytes]. Flowering plants evolved about 140 million years ago, during the late [|Jurassic period]. This development would soon change the face of the Earth.

The many smaller and medium-sized dinosaurs that lived during this time, like [|Xiaosaurus], [|Dryosaurus], [|Kentrosaurus], and [|Stegosaurus], would have browsed on low-lying plants, like [|seed ferns], ferns, horsetails, [|club mosses], and low-lying [|conifers].

Horsetails were an important source of nutrition for plant-eating dinosaurs. These primitive vascular plants were fast-growing and resilient (they could propagate using underground runners which a grazing dinosaur wouldn't eat). This meant that a hungry dinosaur could eat the plant without killing it, since the plant would regrow from the rhizome (the underground stem). || Some other Jurassic plants included: Williamsonia (a cycadeoidphyte), Williamsoniella (a cycadeoid), and Caytonia (a Caytoniale, which led to the flowering plants)
 * [[image:http://www.enchantedlearning.com/hgifs/Horsetail.GIF width="44" height="134"]]

//Williamsonia sewardiana// was a cycadeoidphyte (a bennettitalean). It had a long, thin, woody stem and simple leaves. ||
 * [[image:http://www.enchantedlearning.com/wgifs/Williamsonia.GIF width="96" height="143"]]

**PANGAEA AND WEATHER DURING THE JURASSIC** There was no polar ice during the last two-thirds of the Jurassic. The climate was warm and moist and the sea levels high. There were vast flooded areas, temperate and subtropical forests, and coral reefs. The extensive water moderated the strong seasonality

=The Triassic Period=

248 to 206 Million Years Ago
In many ways, the Triassic was a time of transition. It was at this time that the world-continent of Pangaea existed, altering global climate and ocean circulation. The Triassic also follows the largest extinction event in the history of life, and so is a time when the survivors of that event spread and recolonized. The organisms of the Triassic can be considered to belong to one of three groups: holdovers from the Permo-Triassic extinction, new groups which flourished briefly, and new groups which went on to dominate the Mesozoic world. The holdovers included the [|lycophytes], [|glossopterids], and dicynodonts. While those that went on to dominate the Mesozoic world include modern conifers, cycadeoids, and the [|dinosaurs].

Click on the buttons below to learn more about the Triassic.

Triassic: The chart at left shows the major subdivisions of the Triassic Period. Click to go forward to the Jurassic, or back to the end of the Paleozoic Era, the Permian Period. The Triassic Period is part of the [|Mesozoic Era] =[|Jurassic Period]: Life= Today, the name "Jurassic" conjures up images of the phenomenally successful book and movie, "Jurassic Park". It is quite true that the [|dinosaurs] dominated the land fauna -- although many of the dinosaurs featured in "Jurassic Park", such as [|//Triceratops//] and [|//Tyrannosaurus rex//], did not evolve until after the Jurassic was over. The largest dinosaurs of the time -- in fact, the largest land animals of all time -- were the gigantic [|sauropods], such as the famous //Diplodocus// (pictured at lower left), //Brachiosaurus// and //Apatosaurus//. Other herbivorous dinosaurs of the Jurassic included the plated stegosaurs. Predatory dinosaurs of the Jurassic included fearsome [|carnosaurs] such as //Allosaurus//, small, fast [|coelurosaurs], and [|ceratosaurs] such as [|//Dilophosaurus//]. The Jurassic also saw the origination of the first birds, including the well-known [|//Archaeopteryx//], probably from coelurosaurian ancestors. But there was more to life than dinosaurs! In the seas, the fishlike [|ichthyosaurs] were at their height, sharing the oceans with the plesiosaurs, with giant marine crocodiles, and with modern-looking [|sharks and rays]. Also prominent in the seas were **cephalopods** -- relatives of the squids, nautilus, and octopi of today. Jurassic cephalopods included the **ammonites**, with their coiled external shells (upper left), and the **belemnites**, close relatives of modern squid but with heavy, calcified, bullet-shaped, partially internal shells. Among the plankton in the oceans, the [|dinoflagellates] became numerous and diverse, as did the [|coccolithophorids] (microscopic single-celled algae with an outer covering of calcareous plates). [|Land plants] abounded in the Jurassic, but floras were different from what we see today. Although Jurassic dinosaurs are sometimes drawn with palm trees, there were no palms, or any other flowering plants, at least as we know them today, in the Jurassic. Instead, ferns, [|ginkgoes], bennettitaleans or "cycadeoids", and true [|cycads] -- like the living cycad pictured at the above right -- flourished in the Jurassic. Conifers were also present, including close relatives of living redwoods, cypresses, pines, and yews. Creeping about in this foliage, no bigger than rats, were a number of early [|mammals]. =The Triassic Period=
 * [[image:http://www.ucmp.berkeley.edu/mesozoic/triassic/triassic.gif width="235" height="315" link="http://www.ucmp.berkeley.edu/mesozoic/triassic/triassic.map"]] ||  || Subdivisions of the

248 to 206 Million Years Ago
In many ways, the Triassic was a time of transition. It was at this time that the world-continent of Pangaea existed, altering global climate and ocean circulation. The Triassic also follows the largest extinction event in the history of life, and so is a time when the survivors of that event spread and recolonized. The organisms of the Triassic can be considered to belong to one of three groups: holdovers from the Permo-Triassic extinction, new groups which flourished briefly, and new groups which went on to dominate the Mesozoic world. The holdovers included the [|lycophytes], [|glossopterids], and dicynodonts. While those that went on to dominate the Mesozoic world include modern conifers, cycadeoids, and the [|dinosaurs].

Click on the buttons below to learn more about the Triassic. Dinosaur Fossil Discoveries [|Go to a printable version of this page] The first nearly-complete dinosaur skeleton in New Jersey spurs modern paleontology.** People have been finding dinosaur fossils for hundreds of years, probably even thousands of years. The Greeks and Romans may have found fossils, giving rise to their many ogre and griffin legends. There are references to "dragon" bones found in Wucheng, Sichuan, China (written by Chang Qu) over 2,000 years ago; these were probably dinosaur fossils.
 * The first 3 dinosaur fossils led to the recognition of a new group of animals, the dinosaurs.

Much later, in 1676, a huge thigh bone (femur) was found in England by Reverend Plot. It was thought that the bone belonged to a "giant," but was probably from a dinosaur. A report of this find was published by R. Brookes in 1763.

The First Dinosaur Fossil Scientifically Described The first dinosaur to be described scientifically was [|Megalosaurus]. This genus was named in 1824, by William Buckland; [|Gideon Mantell] (not Ferdinand August von Ritgen) assigned the scientific type species name, //Megalosaurus bucklandii//. Buckland (1784-1856) was a British [|fossil hunter] and clergyman who discovered collected fossils. (Note: the first dinosaur found was [|Iguanodon], but it was named and described later than Megalodon.) It was the first dinosaur ever described scientifically and first [|theropod] dinosaur discovered (this is all in hindsight, because the dinosaurs had not yet been recognized as a separate taxonomic group - the word dinosaur hadn't even been invented yet). The first dinosaur models (life size and made of concrete) were made by Benjamin Waterhouse Hawkins of England in 1854. The first dinosaur used for amusement was a life-size model of an Iguanodon (made by Hawkins) that was used to house a dinner party for scientists (including Richard Owen) at a major exhibition. The invitations to the party were sent on fake pterodactyl wings. The party took place in London, England, in 1854

Other Early Dinosaur Finds || **

[|IGUANODON]** || Gideon A. Mantell (1790-1852) was another early British [|fossil hunter]. He described and named [|Iguanodon], a duck-billed plant-eater (1825); Iguanodon's teeth and a few bones were found in 1822, perhaps by his wife, Mrs. Mary Mantell in Sussex, (southern) England. Gideon Mantell also named [|Hylaeosaurus], an armored plant-eater (1833), and others. || **

[|HYLAEOSAURUS]** ||

The Name "Dinosauria" Sir [|Richard Owen] (1804-1892) was a pioneering British comparative anatomist who coined the term dinosauria (from the Greek "deinos" meaning fearfully great, and "sauros" meaning lizard), recognizing them as a suborder of large, extinct reptiles in 1841. He had noticed that a group of fossils (which included remains of [|Megalosaurus], [|Iguanodon], and [|Hylaeosaurus]) had certain characteristics in common, including: Owen presented dinosaurs as a separate taxonomic group in order to bolster his arguments against the newly proposed theory of evolution (although Darwin's "Origin of the Species" wasn't published until 1859, the basic ideas of evolution were known, but its mechanisms, including natural selection, were not). Ironically, his work actually helped support the evolutionists arguments. This new taxonomic name, Dinosauria, and new group of reptiles was only the beginning of a great scientific exploration. Since Owen's time, about 330 dinosaur genera have been described. Every few months (sometimes every few weeks), a new species is unearthed (for recent finds, see [|Dino News]). Paleontologists have varying estimates of how many dinosaur genera existed during the [|Mesozoic Era]; estimates range from about 1,000 to over 10,000. Whatever this number really is, there are a lot of new dinosaurs left to discover! The First Nearly-Complete Dinosaur Skeleton and First American Dinosaur The first dinosaur fossil found in the US was a thigh bone found by Dr. Caspar Wistar, in Gloucester County, New Jersey, in 1787 (it has since been lost, but more fossils were later found in the area). A Hadrosaur footprint. || In 1800 in Massachusetts, USA, Pliny Moody found 1-foot (31 cm) long fossilized footprints at his farm that were thought by Harvard and Yale scholars to be from "Noah's Raven." Many other dinosaur footprints were been found in New England stone quarries in the early 1800's, but they were thought to be unimportant and were blown up in the quarrying process. Other fragmentary dinosaur bones and tracks were unearthed at this time in Connecticut Valley, Massachusetts. The first nearly-complete dinosaur skeleton was discovered by William Parker Foulke. Foulke had heard of a discovery made by workmen in a [|Cretaceous] marl (a crumbly type of soil) pit on the [|John E. Hopkins farm in Haddonfield, New Jersey] beginning in 1838. Foulke heard of the discovery and recognized its importance in 1858. Unfortunately, some of the bones had already been removed by workmen. The skull-less dinosaur was excavated and named by [|US anatomist] Joseph Leidy who named it [|Hadrosaurus fouki] (meaning "Foulke's big lizard"). It was a [|duck-billed dinosaur] (but it is now a doubtful genus because there is so little fossil information about it). The "Haddonfield Hadrosaurus" is on display at the Philadelphia Academy of Natural Sciences. Leidy's analysis of this Hadrosaur skeleton was thorough; from its anatomy, he wrote imaginitively about the dinosaur's way of life and its death. Leidy wrote, "Hadrosaurus was most probably amphibious; and though its remains were obtained from a marine deposit, the rarity of them in the latter leads us to suppose that those in our possession had been carried down the current of a river, upon whose banks the animals lived." (Quoted from J. Leidy, Account of the Remains of a Fossil Reptile Recently Discovered at Haddonfield, New Jersey. Proceedings Academy of Natural Sciences, Philadelphia, Dec. 14, 1858 pp.1-16.) This study influenced the popular image of dinosaurs and dinosaur science for years. This beautiful skeleton made dinosaurs come to life in peoples' imaginations and spurred generations of [|paleontologists].
 * Column-like legs [[image:http://www.enchantedlearning.com/lgifs/Legsdino.GIF width="43" height="37"]] (instead of the sprawling legs [[image:http://www.enchantedlearning.com/lgifs/Legsreptile.GIF width="63" height="26"]] that other reptiles have)
 * Five fused vertebrae fused to the pelvic girdle.
 * [[image:http://www.enchantedlearning.com/hgifs/Hadrosaurfootprint.GIF width="153" height="118"]]

Triassic: The chart at left shows the major subdivisions of the Triassic Period. Click to go forward to the Jurassic, or back to the end of the Paleozoic Era, the Permian Period. The Triassic Period is part of the [|Mesozoic Era] |||| ** PLACE ** || ** FOSSILS FOUND IN AUSTRALIA Names followed by an asterisk (*) are not dinosaurs, but other interesting fossils Underlined names are links to information sheets. Names in quotation marks are unofficial. ** || (Also see individual states) || [|Agrosaurus], [|Allosaurus], [|Atlascopcosaurus], [|Ausktribosphenos]*, [|Austrosaurus], [|Fulgurotherium], [|Kakuru], [|Kronosaurus*], [|Leaellynasauria], [|Minmi], [|Muttaburrasaurus], [|Ozraptor], [|Platypterygius*], [|Pterodactyloids*], [|Pterosaurs*], "Qantassaurus," [|Rapator], [|Rhoetosaurus], [|Timimus], [|Tylosaurus]*, [|Walgettosuchus], [|Woolungosaurus*] ||
 * || [[image:http://www.ucmp.berkeley.edu/mesozoic/triassic/triassic.gif width="235" height="315" link="http://www.ucmp.berkeley.edu/mesozoic/triassic/triassic.map"]] ||  || Subdivisions of the
 * **Australia**
 * **New South Wales, Australia** || [|Fulgurotherium] ||
 * **New Zealand** || Ankylosaur (probably a nodosaur), Carnosaur, Mosasaur*, Plesiosaur*, Pterosaur*, Sauropod, [|Tylosaurus]* ||
 * **Queensland, Australia** || [|Agrosaurus], [|Austrosaurus], [|Kronosaurus*], [|Minmi], [|Muttaburrasaurus], [|Platypterygius*], [|Rhoetosaurus], [|Woolungosaurus*], and trackways ||
 * **South Australia** || [|Kakuru] ||
 * **Victoria, Australia** || [|Allosaurus], [|Atlascopcosaurus], [|Ausktribosphenos]*, [|Fulgurotherium], [|Leaellynasauria], "Quantassasaurus", [|Timimus] ||
 * **Western Australia** || [|Ozraptor], many trackways ** What is a Dinosaur? ** || Millions of years ago, long before there were any people, there were dinosaurs. Dinosaurs were one of several kinds of prehistoric reptiles that lived during the [|Mesozoic Era], the "Age of Reptiles." || [[image:http://www.enchantedlearning.com/tgifs/Trexanim.gif width="144" height="88" caption="T. rex"]]
 * Dinosaurs were reptiles and most hatched from eggs. No dinosaurs could fly and none lived in the water.** ||


 * [[image:http://www.enchantedlearning.com/bgifs/Brachiosmall.GIF width="108" height="97" caption="Brachiosaurus"]]
 * Plant-eating sauropods were the largest animals to ever walk on Earth - but [|blue whales] are more massive than any of the dinosaurs were!** || The largest dinosaurs were over 100 feet (30 m) long and up to 50 feet (15 m) tall (like [|Argentinosaurus], Seismosaurus, [|Ultrasauros], [|Brachiosaurus], and [|Supersaurus]). The smallest dinosaurs, like [|Compsognathus], were about the size of a chicken. Most dinosaurs were in-between. ||


 * It is very difficult to figure out how the dinosaurs sounded, how they behaved, how they mated, what color they were, or even how to tell whether a fossil was male or female. || [[image:http://www.enchantedlearning.com/dgifs/Dinochecks.GIF width="76" height="54" caption="Dino checks"]]
 * No one knows what color or patterns the dinosaurs were.** ||


 * [[image:http://www.enchantedlearning.com/tgifs/Triceratopsanim.gif width="134" height="86" caption="Triceratops" link="http://www.enchantedlearning.com/subjects/dinosaurs/dinos/Triceratops.shtml"]]
 * Most dinosaurs were plant-eaters (also called herbivores). For example, [|Triceratops] was a plant-eating dinosaur.

Some dinosaurs were meat-eaters (also called carnivores). For example, [|T. rex] was a meat-eating dinosaur.** || There were lots of different kinds of dinosaurs that lived at different times. * Some walked on two legs (they were bipedal), some walked on four (they were quadrupedal). Some could do both.
 * Some were speedy (like [|Velociraptor]), and some were slow and lumbering (like [|Ankylosaurus]).
 * Some were armor-plated, some had horns, crests, spikes, or frills.
 * Some had thick, bumpy skin, and some even had [|primitive feathers]. ||


 * The dinosaurs dominated the Earth for over 165 million years during the [|Mesozoic Era], but mysteriously went extinct 65 million years ago. [|Paleontologists] study their fossil remains to learn about the amazing prehistoric world of dinosaurs. || [[image:http://www.enchantedlearning.com/pgifs/Pangaeatiny.GIF width="77" height="39" caption="Pangaea"]]
 * When the dinosaurs lived, the Earth's continents were jammed together into a supercontinent called Pangaea and the Earth was warmer than it is now.** ||




 * [[image:http://www.enchantedlearning.com/tgifs/Trexskullanim.gif width="86" height="88" caption="T. rex skull"]]
 * The dinosaurs went extinct 65 million years ago, probably because of the environmental changes brought about by an asteroid hitting the Earth.** || [[image:http://www.enchantedlearning.com/vgifs/Volcano.GIF width="82" height="66" align="right" caption="Volcano"]]The dinosaurs went [|extinct] about 65 million years ago, at the end of the [|Cretaceous period], which was a time of high volcanic and [|tectonic activity]. There are a lot of theories why the extinction occurred. The most widely accepted theory is that an asteroid impact caused major climactic changes to which the dinosaurs couldn't adapt. ||


 * [[image:http://www.enchantedlearning.com/bgifs/Bird.GIF width="30" height="26" align="left" caption="Bird"]] Dinosaurs probably live on today as the [|birds]. All that's left of the dinosaurs are [|fossils] and, perhaps,the birds. Dinosaur fossils have been found all over the world, [|maybe even near where you live!] || [[image:http://www.enchantedlearning.com/ugifs/Unen.GIF width="76" height="46" caption="Unenlagia"]]
 * Some dinosaurs were very bird-like and may be the ancestors of today's birds.** ||

The oldest known dinosaur is [|Eoraptor], a meat-eater from about 228 million years ago. ||
 * [[image:http://www.enchantedlearning.com/agifs/Apatoanim.gif width="100" height="52" caption="Apatosaurus"]]
 * There are almost 500 described dinosaur genera and many more species. Every few months (sometimes weeks), [|new finds are unearthed].** || [[image:http://www.enchantedlearning.com/bgifs/Bone.GIF width="32" height="30" align="right" caption="Bone"]]Although dinosaurs' fossils have been known since at least 1818, the term dinosaur (deinos means terrifying; sauros means lizard) was coined by the English anatomist [|Sir Richard Owen] in 1842. The only [|three dinosaurs known at the time] were [|Megalosaurus], [|Iguanodon], and [|Hylaeosaurus], very large dinosaurs.

Dinosaur Timeline Earth history is divided into chunks of time, most importantly aeons, eras and periods. Dinosaurs and other prehistoric reptiles were the dominant animals for about 185 million years during the Mesozoic era, which was a section of the Phanerozoic aeon. More simply, the Mesozoic era lasted from 250 million years ago to 65 million years ago, and contained three periods called the Triassic, Jurassic and Cretaceous. The first reptiles appeared during the ** Palaeozoic Era ** (570 million to 245 million years ago), just before the Each of these eras is divided up into sections called **periods**. Palaeozaic era (say ** pall-ay-oh-zoh-ick ** ) Right: //Fossil trilobites// || || // A fossil nautiloid // || // Fossil of a plant called Archaeopteris from the Devonian period // ||
 * Mesozoic Era ** (245 million to 65 million years ago).
 * 1.
 * Cambrian period ** : (570 million years ago) || The first fishes, corals, trilobites and shellfish appeared.
 * 2.
 * Ordovician period**: (505 million years ago) || The first nautiloids appeared. Corals and trilobites were common. || [[image:http://www.kidcyber.com.au/IMAGES/fossilnautiloid.jpg align="left"]]
 * 3.
 * Silurian period**: (438 million years ago) || The first land plants and giant sea scorpions called //Eurypterids// appeared. || [[image:http://www.kidcyber.com.au/IMAGES/dinoseascorp.jpg align="bottom"]] ||
 * 4.
 * Devonian period**: (408 million years ago) || The first amphibians, insects and spiders appeared. || [[image:http://www.kidcyber.com.au/IMAGES/fossilplant.gif align="left"]]
 * 5. **Carboniforous period**: (360 million years ago) || // The first reptiles appeared // . Great swamp forests covered the land. || [[image:http://www.kidcyber.com.au/IMAGES/carboniferous.jpg align="center"]] ||
 * 6.
 * Permian period:** (286 million years ago) || The first sailback reptiles such as //Dimetrodon// (right) appeared. || [[image:http://www.kidcyber.com.au/IMAGES/dinodimetrodon.jpg align="center"]] ||

Mesozaic era ( // say mezo-zay-ick // ) Dinosaurs included diplodocus, stegasaurus, brachiosaurus. || ||
 * 1. **Triassic period**: 245 million years ago || The first dinosaurs such as Coelophosis and Euskelosaurus, and mammals, turtles, crocodiles and frogs appeared. || [[image:http://www.kidcyber.com.au/IMAGES/dinocoelophysis.jpg align="bottom"]] ||
 * 2. **Jurassic period**: (208 million years ago) || The first birds appeared (e.g. Archaeopteryx).
 * 3. **Cretaceous period**: (144 million years ago) || Dinosaurs during this time included muttaburrasaurus, quetsalcoatlus, ankylosaurus. The dinosaurs died out towards the end of this period.The first snakes and modern mammals appeared. || [[image:http://www.kidcyber.com.au/IMAGES/dinomuttaburra.jpg align="bottom"]] ||

All through this time the earth was changing. In the Triassic period, all the continents were joined together in one huge landmass. Climate was hot and dry but with rain seasons. The first tree ferns and coniferous trees were starting to appear. In the Jurassic period the climate changed as the huge continent was breaking up. There were now forests of cycads, conifers and gingko, all plants that still exist today. In the Cretaceous period the continents had separated and each had its own flora and fauna. However, Australia and Antarctica were still joined together. There were now flowering plants such as magnolias and waterlilies All the continents were joined together as one huge continent, known as Pangaea. When it started to break up towards the end of this period into two continents, the one in the south is known as Gondwanaland. The map shows what Pangea was like, but the continents of today have been drawn on so we can see where they were. If you look at the south, you can see what is now Australia. [|Click here] to read about Pangaea and Gondwanaland At the beginning of the Triassic period, there was the largest extinction of species ever known. About 95% of all species became extinct. The cause is not known, but may have been results of the movement of the continents together, a cooling of the world or volcanic eruptions together with poisonous gases. So during the Triassic period there was the appearance of many new forms of life. There were no dinosaurs at the start of the Triassic period, but there were many amphibians and some reptiles. In the seas, corals appeared and ammonites reappeared. On land, the plants were mainly seed plants and conifers.
 * The Triassic Period **

In the late Triassic, the first mammals appeared. They were tiny, about the size of mice, and probably nocturnal (active at night). The first turtles appeared, as well as frogs, salamanders, lizards and snakes. The dinosaurs were small, and most were quite similar. Pterosaurs, or flying reptiles, appeared during the late Triassic. Insects began to undergo metamorphosis to turn into adults. Marine reptiles appeared. In the plant world, cycads became plentiful. The climate in the Triassic period was hot and dry, causing desert-like conditions. There were seasonal heavy rains however, forming rivers and lakes during the wet season. The polar regions were moist and mild. The end of the Triassic period is also marked by a mass extinction. Pangaea was beginning to break apart, there were huge volcanic eruptions and about 35% of animal species died out. Most of the early dinosaurs became extinct, but some were able to adapt and evolved further during the Jurassic period. Without plamedia type="youtube" key="W0FOZ0-VpcU" height="344" width="425" align="left"nts, there would have been no dinosaurs (or any other land animals).