History of life Final

Eukaryotes

(Any organism whose cells contain a nucleus and other organelles enclosed within membranes) :an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus. Eukaryotes include all living organisms other than the eubacteria and archaebacteria.

Features unique to Dinosaurs

- Unique in the way their legs are held vertically under their body allowing for more support and better motion. -*Ankle* that bends in single plane like a hinge -*Hip* socket with hole in centre -Three or more sacral (located near pelvis) vertebrae

Features of Mammals

-mammals have hair or fur -complex differentiated teeth -jaw and ear bone (more sensitive ear bones) -All mammals are warm-blooded. They can regulate their body temperature. -Female mammals produce milk to nourish their young -Almost all mammals give birth to live young (except for the platypus and echidna)

What generalities can be made about global climate in the Mesozoic?

-lack of polar glaciers -globally warmer than today -relatively high sea level -largest area of dry climates in the Triassic, becoming progressively warmer and wetter till the mid-Cretaceous

Numerical dating/Absolute dating

Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.

Ammonite

Ammonoids are an extinct group of marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs are more closely related to living coleoids than they are to shelled nautiloids such as the living Nautilus species.

amniotes

Amniotes are a clade of tetrapod vertebrates comprising the reptiles, birds, and mammals that lay their eggs on land or retain the fertilized egg within the mother. (all tetrapods excluding amphibians)

Arthropod

An arthropod is an invertebrate animal having an exoskeleton (hard-shelled ), a segmented body, and jointed appendages. Arthropods form the phylum Arthropoda, which includes the insects, arachnids, myriapods, and crustaceans. They appear in the fossil record about 450 million years ago. <-- may be early in cambrian

Major body plans

An assemblage of morphological features shared among many members of a phylum. (one example is the vertebrate body plan). Could be described as a "blueprint" encompassing aspects such as symmetry, segmentation and limb disposition. These body plans are though to have been determined during cambrian explosion.

Haikouichthys

An extinct genus of craniate believed to have lived 525 million years ago, during the Cambrian explosion of multicellular life. May be the "ancestor to all vertebrates" and is one of the earliest known fish.

The hierarchy of biological classification's

Rank is the relative level of a group of organisms (a taxon) in a taxonomic hierarchy. taxonomic ranks: domain, kingdom, phylum, class, order, family, genus, and species.

Relative dating

Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages. The study of strata (horizontal layers of earth) is called stratigraphy, and using a few basic principles, it is possible to work out the relative ages of rocks.

Brachiopods

Soft tissue organisms enclosed in hard shell that extract food from water. First appearing in rocks dating back to the early part of the Cambrian Period, about 525 million years ago. They were extremely abundant during the Paleozoic Era, reaching their highest diversity roughly 400 million years ago, during the Devonian Period.

Cambrian Explosion

The Cambrian explosion or Cambrian radiation was the relatively short evolutionary event, beginning around 541 mya in the Cambrian period, during which most major animal phyla appeared.

Permian mass extinction

The Permian mass extinction has been nicknamed The Great Dying, since a staggering 96% of species died out. All life on Earth today is descended from the 4% of species that survived.

Snowball Earth

The Snowball Earth hypothesis proposes that Earth's surface became entirely or nearly entirely frozen at least once, sometime earlier than 650 Mya (million years ago).

angiosperms

These are the flowering plants, now the most diverse group of land plants. Fossil evidence indicates that flowering plants first appeared in the Lower Cretaceous, about 125 million years ago, and were rapidly diversifying by the Middle Cretaceous, about 100 million years ago. This development gave rise to many new types of insects that carried pollen and increased flowering plant diversity even more.

Late Devonian mass extinction

Three quarters of all species on Earth died out in the Late Devonian mass extinction, though it may have been a series of extinctions over several million years, rather than a single event. Life in the shallow seas were the worst affected.

Trace Fossils

Trace fossils provide us with indirect evidence of life in the past, such as the footprints, tracks, burrows, borings, and feces left behind by animals, rather than the preserved remains of the body of the actual animal itself.

trilobites

Trilobites are a fossil group of extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods. Show up in fossil record 521 million years ago (Cambrian Period)

gymnosperms

a group of *seed-producing plants* that includes conifers, cycads, Ginkgo, and gnetophytes. Most likely originated in the Paleozoic era, during the middle Devonian period about 390 million years ago.

Species

a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. The species is the principal natural taxonomic unit, ranking below a genus and denoted by a Latin binomial, e.g., Homo sapiens.

Clade

a group of organisms believed to have evolved from a common ancestor, according to the principles of cladistics.

prokaryotes

a microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles. Prokaryotes include the bacteria and cyanobacteria.

genus

a principal taxonomic category that ranks above species and below family, and is denoted by a capitalized Latin name, e.g., Leo. (Plural: genera)

amniote egg

a shelled egg protected by amniotic membranes. the shell of the egg provides protection for the developing embryo and allows water retention while still being permeable to gas exchange. This adaptation occurred during the carboniferous period and help animals transition onto land.

Pangea

a supercontinent that existed during the late Paleozoic and early Mesozoic eras (From Permian to Jurassic). It assembled from earlier continental units approximately 300 mya, and it began to break apart about 175 mya.

Biological Family

family is one of the eight major taxonomic ranks; it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks above the rank of genus. Organisms belonging to the same family would have evolved from the same ancestors and share relatively common characteristics.

Taphonomy

the branch of paleontology that deals with the processes of fossilization.

Features of Amphibians

-Amphibians are vertebrates. -Amphibians are cold-blooded. They cannot regulate their own body temperature. -Amphibians spend at least part of their lives in water and on land. -Amphibians do not have scales and their skin is permeable (molecules and gases can pass through). -Amphibians have gills for at least part of their lives. Some species have gills only as larvae, while others can have gills throughout their lives. -Most amphibians go through metamorphosis.

Transition from water to land (plants)

-Coating allowing them to stay moist (Avoid desiccation) -stomata: holes uses to control gas exchange -development of roots (Support weight out of water) -vascular system (development of cellulose) -ability to send spores (reproduction)

How fossils are dated

-Fossils can dated by finding approximate age through comparing to similar rocks or fossils (Relative dating). -Can be dated by the knowledge of what layer of the earth its found at. -Or they can be dated by measuring the the decay of radioactive isotopes (Absolute dating).

Transition from water to land (animals)

-Gills become lungs -development of limps able to support body -skeletal structure changes -development of skin that wouldn't dry out -development of amniote egg (egg shells)

fossile preservation

-Preservation can occur when things get buried in sediment (mud and sand). -Places where sediments can accumulate (won't be weathered away) This tends to happen in water bodies - either quiet water or below large waves. -Water bodies include the ocean (both coastal and deep); shallow continental seas when sea level is high enough to cover parts of continents; and lakes, large rivers, and ponds on land. The generic word for such bowl-shaped places is "basins." -We find fossils where they are at the surface, or near enough to the surface that we can dig down to get them. -Fossils can be preserved in ice in places where the ice has not melted since the Pleistocene ice ages (example, Jarkov mammoth).

Features of Reptiles

-Reptiles have a backbone. They are vertebrates. -Reptiles are covered in scales. -Reptiles breathe with lungs. -Most reptiles lay eggs. -reptiles are cold-blooded

Quaternary Period

1.8 mya to today. know as "The Age of Man". consisting of Pleistocene and Holocene Epochs. Defined as an ice age. Typically defined by the cyclic growth and decay of continental ice sheets driven and the associated climate and environmental changes that occurred. glaciers covered approximately 30 percent of Earth's surface. This period leads up to current times which includes human civilization. Very cold climate and dry climate.

Pleistocene Epoch

1.8 mya- 11,000 ya (.011 mya). "The Last Ice Age". *The first humans (Homo sapiens) evolve.* Mammoths, mastodons, saber-toothed cats, giant ground sloths, and other Pleistocene megafauna. A mass extinction of large mammals and many birds happened about 10,000 years ago, probably caused by the end of the last ice age.

Holocene Epoch

11,000 ya to today. Human civilization.

Cretaceous Period

146 to 65 mya. Lower 146-98 mya: The hey day of the dinosaurs. The first crocodilians, and feathered dinosaurs appear, as well as the earliest-known snakes, ants, and bees. Upper 98-65 mya: High tectonic and volcanic activity. Primitive marsupials develop. Continents have a modern-day look.* Ended with large extinction (the K-T extinction)* of dinosaurs, pterosaurs, ammonites, about 50% of marine invertebrate species, etc., probably caused by asteroid impact or volcanism. Ceratopsians, ankylosaurs, and ornithopods were at their peak in abundance and diversity. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas.

Jurassic Period

208 to 146 mya. Many dinosaurs, including the giant Sauropods. *The first birds appear* (Archaeopteryx). *The first flowering plants evolve (angiosperms)*. Many ferns, cycads, gingkos, rushes, conifers, ammonites, and pterosaurs. Minor extinctions at 190 and 160 mya. Climate: the warm, humid climate allowed lush jungles to cover much of the landscape.

Neogene Period

24-1.8 mya. (Lower Tertiary) Consists of Miocene and Pliocene. *Mammals and birds continued to evolve into roughly modern forms,* while other groups of life remained relatively unchanged. More mammals, including the horses, dogs and bears. Modern birds. South American monkeys, apes in southern Europe, Ramapithecus. *Early hominids*, the ancestors of humans, appeared in Africa near the end of the period. Drastic cooling after paleogene, dryer climate.

Mesozoic Era

248 mya (end of Paleozoic) to 65 mya (beginning of Cenozoic). Known as *the age of reptiles.* Consisting of Triassic Period, Jurassic Period, and Cretaceous Period. *Ending with the Cretaceous-Tertiary or K-T mass extinction,* wiping out the dinosaurs and setting the stage for mammals to thrive. The climate was warmer, the seasons were very mild, the sea level was higher, and there was no polar ice.

Triassic Period

248 to 208 mya. *The first dinosaurs, mammals, and crocodyloformes appear*. Mollusks are the dominant invertebrate. Many reptiles, for example, turtles, ichthyosaurs. True flies appear. Triassic period ends with a minor extinction 213 mya (35% of all animal families die out) This allowed the dinosaurs to expand into many niches. Climate was generally very dry over much of Pangaea with very hot summers and cold winters in the continental interior.

Permian Period

280 to 248 mya. "The Age of Amphibians" - Amphibians and reptiles dominant. Gymnosperms dominant plant life. *The continents merge into a single super-continent, Pangaea.* Phytoplankton and plants oxygenate the Earth's atmosphere to close to modern levels. Time when Dimetrodon lived. The Permian ended with *largest mass extinction.* Trilobites go extinct, as do 50% of all animal families and 96% of species. nicknamed "The Great Dying". The emerging supercontinent of Pangaea presented severe extremes of climate and environment due to its vast size. The south was cold and arid, with much of the region frozen under ice caps.

Carboniferous Period (Pennsylvanian, Mississippian).

360 to 280 mya. First winged insects. First reptiles. Many ferns. The first mayflies and cockroaches appear. *Landscape covered in moist swam filled forests*. Amphibians become more common. the amniote egg develops, which allowed for the further exploitation of the land by certain tetrapods. *Reptiles first appear.* lack of organisms to destroy them resulted in *giant trees which produced more oxygen allowing insects to grow larger.* Deposition of these large trees in swamps lead to *great amounts of coal being produced.*

Pre Cambrian Eon

4.6 bya (4,600 mya) to 541 mya. Earths crust solidifies, single celled organisms( prokaryotes) arise, blue- green algae, archaeans, bacteria. *The age of bacteria begins which begins to free oxygen into the atmosphere*. Multicellular life develops giving rise to Eukaryotes setting the stage for more complex organisms.

Devonian Period

408 to 360 mya. Know as "The Age of Fishes". Fish and land plants become abundant and diverse. *First tetrapods appear* toward the end of the period. *First amphibians appear.* *First land vertebrates.* First sharks, bony fish, and ammonoids. Many coral reefs, brachiopods, crinoids. New insects, like springtails, appeared. Mass extinction (345 mya) wiped out 30% of all animal families, 75% of all species) probably due to glaciation or meteorite impact. The Devonian was a relatively warm period, and probably lacked any glaciers. The weather was also very arid, mostly along the equator where it was the driest.

Silurian Period

438 to 408 mya. *The first jawed fishes* and uniramians (like insects, centipedes and millipedes). *First vascular plants* (plants with water-conducting tissue as compared with non-vascular plants like mosses) *appear on land* (Cooksonia is the first known). High seas worldwide. Brachiopods, crinoids, corals. Nautiloids and arthropods such as Orthocone, and Brontoscorpio. By the middle of the Silurian it became much warmer, comparable to that of most of the Ordovician and Devonian Periods. A new greenhouse phase began, leading to the melting of many large glacial ice sheets, which contributed to a substantial rise in global sea level.

Pliocene Epoch

5-1.8 mya. *First hominids* (australopithecines). Modern forms of whales. Megalodon swam the seas.

Ordovician Period

505 to 438 mya. *Primitive plants appear on land. First corals.* Primitive fishes, seaweed and fungi. Know for diverse marine invertebrates, including graptolites, trilobites, brachiopods, and the conodonts (early vertebrates). First arthropods. High sea levels at first, global cooling and glaciation, and much volcanism. North America under shallow seas. Ends in huge extinction, due to glaciation. From the Lower to Middle Ordovician, the Earth experienced a milder climate it was warm and there was a lot of moisture. Then during the Upper Ordovician, massive glaciers formed, causing shallow seas to drain and sea levels to drop.

Phanerozoic Eon

540 mya to today. Organisms with skeletons or hard shells come into existence *(Vertebrate life).*

Cambrian Period

540 to 500 mya. Labeled "The Age of Trilobites". *The Cambrian Explosion* occurs giving rise to complex marine animals, including all existing phyla. Predator/ prey model develops. Many marine invertebrates (marine animals with mineralized shells: shell-fish, echinoderms, trilobites, brachiopods, mollusks, primitive graptolites). *First vertebrates develop*, including primitive fish, giving rise to major body plans. Ends with extinction event. In the early Cambrian, Earth was generally cold but was gradually warming as the glaciers of the late Proterozoic Eon receded.

Cenozoic Era

65 mya (end of Mesozoic) to today. Know as *the age of mammals*. consisting of the Tertiary Period (Neogene, Paleogene), and Quaternary Period. Each segment of the Cenozoic experienced different climates. During the Paleogene Period, most of the Earth's climate was tropical. The Neogene Period saw a drastic cooling, which continued into the Pleistocene Epoch of the Quaternary Period

Paleogene Period

65-24 mya. (Upper Tertiary) consists of the Paleocene, Eocene, and Oligocene Epochs. Most notable for being the time during which *mammals diversified* from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous-Paleogene extinction event. primitive primates appear as well rodents. Many new mammals (pigs, deer, cats, rhinos, tapirs appear). Grasses common. Climate was warmer and more tropical than today.

cephalopods

A cephalopod is any member of the molluscan class Cephalopoda. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot.

Amphibians

A cold-blooded vertebrate animal of a class that comprises the frogs, toads, newts, and salamanders. They are distinguished by having an aquatic gill-breathing larval stage followed (typically) by a terrestrial lung-breathing adult stage. First appeared on Earth during the Devonian period, more than 400 million years ago. It was during the Carboniferous period that amphibians flourished.

Gastrolith

A gastrolith is a rock that is swallowed by creatures used to grind food in animals lacking suitable grinding teeth. Many dinosaurs that lacked teeth needed to break up vegetation used these. Commonly used by Sauropods.

Synapsid

A group of animals that includes mammals and every animal more closely related to mammals than to other living amniotes. They are easily separated from other amniotes by having a *temporal fenestra*, an opening low in the skull roof behind each eye. The synapsid lineage became distinct from the sauropsid lineage in the late Carboniferous period, *between 320 and 315 million years ago.*

Theropods

A group of carnivore dinosaurs that first appeared during the late Triassic period 231.4 million years ago. Defined by their diet and bipedality they were some of the largest land carnivores to ever exist. It is thought that many theropods actually had feathers. This is the group of dinosaurs that would later evolve into birds. Most commonly know species are the T-rex and Allosaurus.

Archosaurs

A group of diapsid amniotes whose living representatives consist of birds and crocodilians. This group also includes all extinct non-avian dinosaurs, extinct crocodilian relatives, and pterosaurs. The ancestral archosaurs probably originated some 250 million years or so ago, in the late Permian period. *Species in this group are united anatomically by the hole in front of their eye socket.*

Ceratopsians

A group of herbivorous, beaked dinosaurs that thrived in the Cretaceous period. Know for being large and robust with horns and bony frills around the back of their heads. They first appeared around 155 mya during the Jurassic Period. Most commonly know species is Triceratops. diversify in North America and in Asia.

therapsids

A group of more advanced synapsids that includes mammals and their ancestors. Many of the traits today seen as unique to mammals had their origin within early therapsids, including having their four limbs extend vertically beneath the body. Therapsids evolved 275 million years ago and included the cynodonts, the group that gave rise to mammals in the Late Triassic around 225 million years ago.

extraterrestrial impact hypothesis

A hypothesis for what could have caused the mass extinction at the end of cretaceous that killed of dinosaur, that explains the occurrence with the impact of a giant impact (asteroid). First discovered because high concentrations of a "rare-earth" element, iridium, was found at the Cretaceous-Paleogene boundary. Main cause of extinction: dust clouds that block sunlight, decreasing temperature and preventing photosynthesis, thus disrupting the food chain.

Living Fossil

A living fossil is a living species (or clade) of organism that closely resembles species otherwise known only from the fossil record. Some examples are Sharks, Crocodiles, and Horseshoe Crabs.

Phyla

A scientfic way of grouping together related organisms. All the members of a phylum have a common ancestor and anatomical similarities. For instance, all the arthropods have external skeletons. Phlya are large groups and are further subdivided into classes, orders, families and so on.

Geologic Time scale

A system of chronological dating that relates geological strata (stratigraphy) to time, and is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events that have occurred during Earth's history. Time spans in geochronology: Eon, Era, Period, Epoch. Helpful website: http://www.enchantedlearning.com/subjects/Geologictime.html

Ankylosaurs

A type of armored dinosaur that lived during the late cretaceous period, around 66 mya. Ankylosaurs were massive armored herbivores. They has low skulls with two horns pointing backward, and large clubs on the end of their tails. Most commonly know species is the Ankylosaurus.

Sauropods

A type of dinosaur that first appeared in the late Triassic Period. There group includes the largest animals to have ever lived on land. They were herbivorous, had very long necks, long tails, small heads, and four thick, pillar-like legs. By the Late Jurassic (150 million years ago), sauropods had become widespread (especially the diplodocids and brachiosaurids).

Ornithopods

A type of dinosaur that first appeared in the triassic period. These dinosaurs that started out as small, bipedal running grazers, and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world. Most commonly know species Iguanodon. They had teeth adapted to break up all types of vegetation.

Pterosaurs

A type of flying reptile that appeared in the late triassic and lived until the extinction event at the end of the cretaceous. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger. Most commonly know species is the pterodactyl.

Ichthyosaurs

A type of large marine reptile that first appeared approximately 250 million years ago (late permian/early triassic) and went extinct in the late cretaceous. Ichthyosaurs resembled both modern fish and dolphins. Their limbs had been fully transformed into flippers, and were equipped with conical teeth to catch smaller prey. They were the top aquatic predator until being replaced by plesiosaurs. Ichthyosaurs were air-breathing, bore live young, and were probably warm-blooded.

Plesiosaurs

A type of marine reptile that first appeared in the late triassic period. Plesiosaurs had a broad flat body and a short tail, their limbs had evolved into four long flippers, which were powered by strong muscles. They became especially common during the Jurassic Period. The flippers made a flying movement through the water. Plesiosaurs breathed air, and bore live young; there are indications that they were warm-blooded.

Stegosaurs

A type of of armored dinosaur that first appeared during the late Jurassic Period, about 150 mya. They were large, heavily built, herbivorous quadrupeds with rounded backs, short fore limbs, long hind limbs, and tails held high in the air. Recognized by their upright plates and tail tipped with spikes. Most commonly know species is stegosaurus. Their plates may have been uses to absorb heat or scare off predators.

Mammals

A warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur, the secretion of milk by females for the nourishment of the young, and (typically) the birth of live young. The Mammals represent the only living Synapsida. Mammals *first appear around 200 mya*, in the triassic period.

dinosaur of special significance to NY State

Coelophysis

Terapod

Comprises the first four-limbed vertebrates and their descendants, including the living and extinct amphibians, birds, mammals, reptiles. *Tetrapods evolved from the lobe-finned fishes around 390 million years ago in the middle Devonian Period*, with modern tetrapod groups having appeared by the late Devonian, 367.5 million years ago.

Diapsid

Diapsids ("two arches") are a group of amniote tetrapods that developed two holes (temporal fenestra) in each side of their skulls about 300 million years ago during the late Carboniferous period.

Dinosaur

Dinosaurs are a diverse group of animals that first appeared during the Triassic period. The current scientific consensus places their origin between 231 and 243 million years ago. They became the dominant terrestrial vertebrates after the Triassic-Jurassic extinction event 201 million years ago. Their dominance continued through the Jurassic and Cretaceous periods and ended when the Cretaceous-Paleogene extinction event led to the extinction of most dinosaur groups 66 million years ago.

Mammal-like Reptiles/ Stem-Animals/ non-mammalian synapsids (pelycosaurs).

First appeared about 285 million years ago (late carboniferous) near the beginning of the Permian. These creatures are more closely related to mammal then reptiles, but don't fit into the mammal classification. They evolved quickly and many different groups arose. The most common know species is Dimetrodon. The term mammal-like reptile isn't used anymore and these animals are just refers to as non-mammal synapsids.

Nautiloids

Free swimming animals that possess a head with two simple lens-free eyes and tentacles. They have a smooth shell over a large body chamber, which is divided into subchambers filled with an inert gas making the animal neutrally buoyant in the water. Nautiloids are a large and diverse group of marine cephalopods (Mollusca) belonging to the subclass Nautiloidea that began in the Late Cambrian and are represented today by the living Nautilus and Allonautilus..

Paleozoic Era

From 540 mya (end of Pre-Cambrian) to 248 mya (beginning of Mesozoic). Consists of the Cambrian Period, Ordovician Period, Silurian Period, Devonian Period, Carboniferous Period, and Permian Period. *Ending with the Permian mass extinction*, nicknamed "The Great Dying", since a staggering 96% of species died out. The climate of the Paleozoic Era varied as the period began with large glaciers covering the surface of the Earth, which gave way to warmer temperatures, glacial melt and volcanic activity.

Cretaceous-Tertiary /K-T mass extinction

Is famed for the death of the dinosaurs. However, many other organisms perished at the end of the Cretaceous including the ammonites, many flowering plants and the last of the pterosaurs. Extinction of "non-avian" dinosaurs, plesiosaurs, ichthyosaurs, pterosaurs, many marine plankton, ammonites, reef-forming clams, and others. Dust clouds -> blocks sunlight -> cooling & decreased photosynthesis ->food chain disrupted + acid rain. Animals most likely to survive were hibernating or small burrowing creatures that didn't rely on fresh vegetation.

What kind of fossils would you expect to find if you looked in stream beds north of Ithaca?

•brachiopods •trilobites •horn corals