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9th grade biology 1 Qt Trail Talking Points Evolutionary History/History of Life and Classification of Kingdoms st Photosynthetic Organisms • • • • • • • • • • • Photosynthesis is a process used by plants and other organisms to convert the light energy captured from the sun into chemical energy that can be used to fuel the organism's activities. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea The first photosynthetic organisms probably evolved about 3,500 million years ago, early in the evolutionary history of life, when all forms of life on Earth were microorganisms and the atmosphere had much more carbon dioxide. They most likely used hydrogen or hydrogen sulfide as sources of electrons, rather than water.[8] Cyanobacteria appeared later, around 3,000 million years ago, and drastically changed the Earth when they began to oxygenate the atmosphere, beginning about 2,400 million years ago.[9] This new atmosphere allowed the evolution of complex life such as protists. Eventually, no later than a billion years ago, one of these protists formed a symbiotic relationship with a cyanobacterium, producing the ancestor of many plants and algae.[10] The chloroplasts in modern plants are the descendants of these ancient symbiotic cyanobacteria.[11] (see the Endosymbiosis Theorgy) These other organisms provide clues to the evolution of all photosynthetic organisms. All of these organisms - plants, green algae, and the protists - are primary photosynthetic eukaryotic organisms. Primary evidence comes from around 3000 Ma, in rock records and fossil evidence of cyanobacteria, photosynthesizing prokaryotic organisms. Cyanobacteria use water as a reducing agent, thereby producing atmospheric oxygen as a byproduct, and profoundly changing the early reducing atmosphere of the earth to one in which modern aerobic organisms eventually evolved. This oxygen liberated by cyanobacteria then oxidized dissolved iron in the oceans, the iron precipitated out of the sea water, and fell to the ocean floor to form sedimentary layers of oxidized iron called Banded Iron Formations (BIFs). These BIFs are part of the geological record of evidence for the evolutionary history of plants by identifying when photosynthesis originated. Endosymbiosis theory and mitochondria and chloroplasts • • • • • • • • • • • The endosymbiosis theory attempts to explain the origins of organelles such as mitochondria and chloroplasts in eukaryotic cells. The theory proposes that chloroplasts and mitochondria evolved from certain types of bacteria that eukaryotic cells engulfed through endophagocytosis. These cells and the bacteria trapped inside them entered a symbiotic relationship, a close association between different types of organisms over an extended time. However, more specifically, the relationship was endosymbiotic, meaning that one of the organisms (the bacteria) lived within the other (the eukaryotic cells). Many instances of endosymbiosis are obligate; that is, either the endosymbiont or the host cannot survive without the other. It is generally agreed that certain organelles of the eukaryotic cell, especially mitochondria and plastids such as chloroplasts, originated as bacterial endosymbionts. There are several examples of evidence that support endosymbiosis theory.[2] Mitochondria and chloroplasts contain their own small supply of DNA, which may be remnants of the genome the organelles had when they were independent aerobic bacteria. The single most convincing evidence of the descent of organelles from bacteria is the position of mitochondria and plastid DNA sequences in phylogenetic trees of bacteria. Mitochondria have sequences that clearly indicate origin from a group of bacteria called the alpha-Proteobacteria. Plastids have DNA sequences that indicate origin from the cyanobacteria (blue-green algae). In addition, there are organisms alive today, called living intermediates, that are in a similar endosymbiotic condition to the prokaryotic cells and the aerobic bacteria. Living intermediates show that the evolution proposed by the endosymbiont theory is possible. Cyanobacteria are arguably the most successful group of microorganisms on earth. They are the most genetically diverse; they occupy a broad range of habitats across all latitudes, widespread in freshwater, marine and terrestrial ecosystems, and they are found in the most extreme niches such as hot springs, salt works, and hypersaline bays. Photoautotrophic, oxygen-producing cyanobacteria created the conditions in the planet's early atmosphere that directed the evolution of aerobic metabolism and eukarotic photosynthesis. Cyanobacteria fulfill vital ecological functions in the world's oceans, being important contributors to global carbon and nitrogen budgets. Cyanobacteria have an elaborate and highly organized system of internal membranes which function in photosynthesis. Cyanobacteria get their color from the bluish pigment phycocyanin, which they use to capture light for photosynthesis. Photosynthesis in cyanobacteria generally uses water as an electron donor and produces oxygen as a by-product, though some may also use hydrogen sulfide as occurs among other photosynthetic bacteria. Plant Divisions The Plantae includes all land plants: mosses, ferns, conifers, flowering plants, and so on—an amazing range of diverse forms. With more than 250,000 species, they are second in size only to the arthropoda. Plants have been around for a very long time. The plants first appeared in the Ordovician, but did not begin to resemble modern plants until the Late Silurian. By the close of the Devonian, about 360 million years ago, there were a wide variety of shapes and sizes of plants around, including tiny creeping plants and tall forest trees. Plants are divided into two major groups: Non-vascular plants -- bryophytes -- require a constantly moist environment. They include: • • mosses & liverworts. Bryophytes: Mosses and Liverworts Bryophytes, most commonly represented by mosses have the following characteristics: • • • • • • • • • • • photosynthetic nonvascular (no xylem or phloem) dominant gametophyte homospory (only one type of spore is produced) swimming sperm cells stay small and close to the ground require moisture for reproduction and growth lack true stems, leaves and roots (they have rhizoids which anchor but absorb little water) They can be found on soil, rocks, and the bark of trees, and in bogs and shallow streams. The gametophyte's organs of sexual reproduction, called antheridia and archegonia, contain sperm and egg, respectively Fertilization can take place only when the plants are wet; after fertilization, the egg grows into a sporophyte. The sporophyte consists of a base, or foot, embedded in gametophyte tissue; a stalk that is usually long and slender; and a terminal capsule. The capsule, which in most species is covered by a small-toothed lid, contains numerous spores. (see below) • • After flowering plants and ferns, mosses are the most diverse group of plants, with more than 10,000 species in 700 genera. This makes mosses almost twice as diverse as mammals. Mosses don't receive as much attention from us as flowering plants, ferns, or conifers because most mosses are small and inconspicuous. They have no vascular tissue or wood to lend them structural support, nor do they have large leaves or showy cones or flowers. This does not mean that mosses are not important; in fact, mosses play important roles in reducing erosion along streams, water and nutrient cycling in tropical forests, and insulating the arctic permafrost. Vascular plants or tracheophytes include: Seedless vascular plants such as • • • • club mosses horsetails ferns (pterophyta) which are the most numerous of this type of plant Spores were the main way that plants spread over Earth for the first 100 million years of life on land. Horsetails – Family: Equisetaceae • • • • Equisetum is a "living fossil", as it is the only living genus of the entire class Equisetopsida, which for over one hundred million years was much more diverse and dominated the understory of late Paleozoic forests. Some Equisetopsida were large trees reaching to 30 meters tall;[3] the genus Calamites of family Calamitaceae for example is abundant in coal deposits from the Carboniferous period. They grow from perennial creeping rhizomes, from which grow a single hollow, jointed stem, with bristle-like branches growing from the joints. Horsetails reproduce by means of spores. The spores are contained in small cones at the tips of the stem or its branches, or sometimes on a separate stalk in the spring. The leaves of horsetails grow in whorls fused into nodal sheaths. The stems are green and photosynthetic, and distinctive in being hollow, jointed and ridged There may or may not be whorls of branches at the nodes; when present, these branches are identical to the main stem except being smaller and more delicate. • • • In these plants the leaves are greatly reduced and usually non-photosynthetic photosynthetic. Equisetum stores granules of silica within its cells, making it an effective tool for scrubbing pots and polishing wood and polishing metal. Are related to ferns. Ferns • • • • about 12,000 species of plants belonging to the botanical group known as Pteridophyta Ferns reproduce via spores and have neither seeds nor flowers. Ferns first appear in the fossil record 360 million years ago in the Carboniferous but many of the current families and species did not appear until roughly 145 million years ago in the early Cretaceous (after flowering plants came to dominate nate many environments). Like all other vascular plants, they have a life cycle referred to as alternation of generations,, characterized by alternating diploid sporophytic and haploid gametophytic phases. Life cycle of a typical fern: • • • • • A diploid sporophyte phase produces haploid spores by meiosis (a process of cell division which reduces the number of chromosomes by a half). A spore grows into a haploid gametop gametophyte hyte by mitosis (a process of cell division which maintains the number of chromosomes). The gametophyte typically consists of a photosynthetic prothallus. The gametophyte produces gametes (often both sperm and eggs on the same prothallus) by mitosis mitosis. A mobile, flagellate sperm fertilizes an egg that remains attached to the prothallus. The fertilized egg is now a diploid zygote and grows by mitosis into a diploid sporophyte (the typical "fern" plant). (In Other Words) • • • Spores from the parent fall to the ground and with an enormous amount of luck (millions perish for every success) they will find suitable moisture and light. The tiny single-celled organism starts to grow by cell division. Soon orderly arrangements of cells form little green heart shaped plants or Prothallia (gametophytes). These plants go unnoticed by most people as they are only 1/2 inch or less across and lie flat on the ground. This is an independent plant with its own simple "root" system (rhizoids) to provide it with nutrients and water. The Prothallium then grows Antheridia or male organs and Archegonia or female organs on its underside. The Antheridium produces spermatazoids (or antherozoids) which will swim via a droplet of water to the egg produced by the Archegonium. The fertilized egg then begins to grow the Sporophyte, the plant that we know as a fern. Leaves are divided into three types: o Trophophyll: A leaf that does not produce spores, instead only producing sugars by photosynthesis. Analogous to the typical green leaves of seed plants. o Sporophyll: A leaf that produces spores. These leaves are analogous to the scales of pine cones or to stamens and pistil in gymnosperms and angiosperms, respectively. Unlike the seed plants, however, the sporophylls of ferns are typically not very specialized, looking similar to trophophylls and producing sugars by photosynthesis as the trophophylls do. Seed Plants – Spermatophytes Seed- bearing plants. The success of seed plants (gynmosperms and angiosperms may be attributed to: • • • development of an extensive root system an efficient vascular system (xylem and phloem) reproductive structure in which the gametophyte is protected inside sporophyte tissue (the seed) The seed plants include: • • naked-seed plants (such as conifers), known as gymnosperms and flowering plants, the angiosperms. flowering plants may be divided into the o o monocots (parallel veins in blade-like leaves and flower parts in multiples of 3) dicots (cotyledon divided into two parts, flower parts in multiples of 4 or 5) The spermatophytes, which means "seed plants", are some of the most important organisms on Earth. Life on land as we know it is shaped largely by the activities of seed plants. Soils, forests, and food are three of the most apparent products of this group. • • • • Seed-producing plants are probably the most familiar plants to most people, unlike mosses, liverworts, horsetails, and most other seedless plants which are overlooked because of their size or inconspicuous appearance. Many seedplants are large or showy. Conifers are seed plants; they include pines, firs, yew, redwood, and many other large trees. The other major group of seed-plants are the flowering plants, including plants whose flowers are showy, but also many plants with reduced flowers, such as the oaks, grasses, and palms. The earliest seed plants produced their seeds along their branches without specialized structures, such as cones or flowers, unlike most living seed plants. The oldest known seed plant is Elkinsia polymorpha, a "seed fern" from Late Devonian (Famennian) of West Virginia. Heterospory is the rule among seed plants. • Nearly all seedless plants are homosporous, producing a single kind of spore that forms a hermaphroditic gametophyte. • Seed plants likely had homosporous ancestors. • All seed plants are heterosporous, producing two different types of sporangia that produce two types of spores. • Megasporangia produce megaspores, which give rise to female (egg-containing) gametophytes. • Microsporangia produce microspores, which give rise to male (sperm-containing) gametophytes. Seed plants produce ovules. • A female gametophyte develops from a megaspore and produces one or more egg cells. Pollen eliminated the liquid-water requirement for fertilization. • The microspores develop into pollen grains that are released from the microsporangium. • They are carried by wind or animals. • The transfer of pollen to the vicinity of the ovule is called pollination. • The pollen grain germinates and grows as a pollen tube into the ovule, where it delivers one or two sperm into the female gametophyte. • Bryophytes and seedless vascular plants have flagellated sperm cells that swim a few centimeters through a film of water to reach the egg cells within the archegonium. • In seed plants, the female gametophyte is retained within the sporophyte ovule. • Male gametophytes travel long distances as pollen grains. • The sperm of seed plants lack flagella and do not require a film of water, as they rely on the pollen tube to reach the egg cell of the female gametophyte within the ovule. • The sperm of some gymnosperm species retain the ancestral flagellated condition, providing evidence of this evolutionary transition. • The evolution of pollen contributed to the success and diversity of seed plants. Seeds became an important means of dispersing offspring. • The evolution of the seed enabled plants to resist harsh environments and disperse offspring more widely. • Coevolution is the mutual evolutionary influence between two species (the evolution of two species totally dependent on each other). Each of the species involved exerts selective pressure on the other, so they evolve together. Coevolution is an extreme example of mutualism. Some examples of coevolution include: Insects, bats and flowering plants, lichens, • The seed represents a different solution to resisting harsh environments and dispersing offspring. o In contrast to a single-celled spore, a multicellular seed is a much more complex, resistant structure. o After being released from the parent plant, a seed may remain dormant for days or years. o Under favorable conditions, it germinates and the sporophyte embryo emerges as a seedling. Invertebrates • Invertebrates were the first animals to evolve. • The oldest fossil of an invertebrate dates back to the late Precambrian, about 600 million years ago. • Invertebrates account for 97 percent of all known species. Evolution of Vertebrates Classroom Preparation and Equipment: Alligator, scute, egg Gopher tortoise, yellow bellied slider shell Snake Opossum Owl Bird skeleton Rabbit skeleton Toad or Frog Salamander We'll look at the various groups of vertebrates in the order in which they evolved to create a picture of how vertebrate evolution unfolded to the present day. • The defining characteristic of vertebrates is their backbone, an anatomical feature that first appeared in the fossil record about 500 million years ago, during the Ordovician period. Jawless Fish (Class Agnatha) • • • • • • The first vertebrates were the jawless fish (Class Agnatha). These fish-like animals had hard bony plates that covered their bodies and as their name implies, they did not have jaws. These early fish did not have paired fins. The jawless fish are thought to have relied on filter feeding to capture their food, and most likely would have sucked water and debris from the seafloor into their mouth, releasing water and waste out of their gills. The jawless fish that lived during the Ordovician period all went extinct by the end of the Devonian period. The modern day jawless fish (hagfish and lampreys) are not direct survivors of the Class Agnatha but are instead distant cousins of the cartilaginous fish. Armored Fish (Class Placodermi) • • • The armored fish evolved during the Silurian period. Like their predecessors, they too lacked jaw bones but possessed paired fins. The armored fish diversified during the Devonian period but declined and fell into extinction by the end of the Permian period. Cartilaginous Fish (Class Chondrichthyes) • Cartilaginous fish, better known as sharks, skates, and rays evolved during the Silurian period. • • Cartilaginous fish have skeletons composed of cartilage, not bone. They also differ from other fish in that they lack swim bladders and lungs. Bony Fish (Class Osteichthyes) • • • • Members of the Class Osteichthyes first arose during the late Silurian. The majority of modern fish belong to this group (note that some classification schemes recognize the Class Actnopterygii instead of Osteichthyes). Bony fish diverged into two groups, one that evolved into modern fish, the other that evolved into lungfish, lobe-finned fish, and fleshy-finned fish. Lobe-finned fish gave rise to the amphibians Amphibians (Class Amphibia) • • • • • • • • • • • • • Developed in the Devonian period from lobe-finned fish similar to the modern coelacanth and lungfish, which had evolved multi-jointed leg-like fins with digits that enabled them to crawl along the sea bottom. Eventually, their bony fins would evolve into limbs and they would become the ancestors to all tetrapods, including modern amphibians, reptiles, birds, and mammals Early amphibians retained many fish-like characteristics. During the Carboniferous period amphibians diversified-more time on land. They retained close ties to water though, producing fish-like eggs that lacked a hard protective coating and requiring moist environments to keep their skin damp. Additionally, amphibians underwent larval phases that were entirely aquatic and only the adult animals were able to tackle land habitats. At the end of the Devonian period (360 million years ago), the seas, rivers and lakes were teeming with life but the land was the realm of early plants and devoid of vertebrates [7] though some, such as Ichthyostega, may have sometimes hauled themselves out of the water.[ In the early Carboniferous (360 to 345 million years ago), the climate became wet and warm. Extensive swamps developed with mosses, ferns, horsetails and calamites. Air-breathing arthropods began to evolve and invaded the land where they provided food for the carnivorous amphibians that began to emerge from the waters. There were no other tetrapods on the land and the amphibians were at the top of the food chain, occupying the ecological position currently held by the crocodile. They were the top land predators, sometimes reaching several meters in length, preying on the large insects of the period and many types of fish in the water. They still needed to return to water to lay their shell-less eggs, and even modern amphibia have a fully aquatic larval stage with gills like their ancestral fish. It was the development of the amniotic egg, which prevents the developing embryo from drying out, that enabled the reptiles to reproduce on land and which led to their dominance in the period that followed.[4] • • During the Triassic Period (250 to 200 million years ago), the reptiles began to outcompete the amphibians, leading to a reduction in both the amphibians' size and their importance in the biosphere. According to the fossil record, Lissamphibia, which includes all modern amphibians and is the only surviving lineage, may have branched off from the extinct groups Temnospondyli and Lepospondyli at some period between the Late Carboniferous and the Early Triassic. Reptiles (Class Reptilia) • • • • • Reptiles arose during the Carboniferous period and quickly took over as the dominant vertebrate of the land. Reptiles freed themselves from aquatic habitats where amphibians had not. Reptiles developed hard-shelled eggs that could be laid on dry land. They had dry skin made of scales that served as protection and helped retain moisture. Reptiles developed larger and more powerful legs than those of amphibians. The placement of the reptilian legs beneath the body (instead of at the side as in amphibians) enabled them greater mobility. Four currently recognized Orders: • • • • Crocodilia (crocodiles, gavials, caimans, and alligators): 23 species Sphenodontia (tuataras from New Zealand): 2 species Squamata (lizards, snakes, and worm lizards): approximately 7,900 species Testudines (turtles, terrapins and tortoises): approximately 300 species Birds (Class Aves) Sometime during the early Jurassic, two groups of reptiles gained the ability to fly and one of these groups later gave rise to the birds. Birds developed a range of adaptations that enabled flight such as feathers, hollow bones, and warm-bloodedness. Mammals (Class Mammalia) Mammals, like birds, evolved from a reptilian ancestor. Mammals developed a fourchambered heart, hair covering, and most do not lay eggs and instead give birth to live young (the exception is the monotremes). Reptile Talking Points-General • • • • • • • Reptiles originated around 320-310 million years ago during the Carboniferous period, having evolved from advanced reptile-like amphibians that became increasingly adapted to life on dry land. There are many extinct groups, including dinosaurs, pterosaurs, and aquatic groups such as the ichthyosaurs Modern reptiles inhabit every continent with the exception of Antarctica. Several living sub-groups are recognized: • Testudines (turtles, terrapins and tortoises): over 300 species • Sphenodontia (tuataras from New Zealand): 2 species • Squamata (lizards, snakes, and worm lizards): approximately 9,150 species[2] • Crocodilia (crocodiles, gavials, caimans, and alligators): 23 species Reptiles are tetrapod vertebrates, either having four limbs or, like snakes, being descended from four-limbed ancestors. The evolution of lungs and legs are the main transitional steps towards reptiles, but the development of hard-shelled external eggs replacing the amphibious water bound eggs is the defining feature of the class reptilia (with the exception of certain squamates) and is what allowed amphibians to fully leave water. Increasing evolutionary pressure and the vast untouched niches of the land powered the evolutionary changes in amphibians to gradually become more and more land based. A series of footprints from the fossil strata of Nova Scotia, dated to 315 million years show typical reptilian toes and imprints of scales.[4] The tracks are attributed to Hylonomus, the oldest unquestionable reptile known.[5] It was a small, lizard-like animal, about 20 to 30 cm (8–12 in) long, with numerous sharp teeth indicating an insectivorous diet Gopher Tortoise- a family of land-dwelling reptiles in the order Testudines. Turtles (Testudines) are an ancient group of reptiles that includes more than 293 species. The first turtles appeared more than 220 million years ago during the late Triassic Period. Since that time, turtles have changed little. The first proto-turtles are believed to have existed in the late Triassic Period of the Mesozoic era, about 220 million years ago, and their shell, which has remained a remarkably stable body plan, is thought to have evolved from bony extensions of their backbones and broad ribs that expanded and grew together to form a complete shell that offered protection at every stage of its evolution, even when the bony component of the shell was not complete. Family Testudinidae Subfamily Xerobatinae • Gopherus o Gopherus agassizii, Mojave Desert Tortoise, Agassiz's Desert Tortoise o Gopherus berlandieri, Texas Tortoise, Berlandier's Tortoise o Gopherus flavomarginatus, Bolson Tortoise o o Gopherus morafkai, Sonoran Desert Tortoise, Morajak's Desert Tortoise Gopherus polyphemus, Gopher Tortoise Order-Crocodilia Family - Alligatoridae American Alligator • • • • Alligators first appeared during the Oligocene epoch about 37 million years ago.[1] There are two living alligator species: the American alligator (Alligator mississippiensis) and the Chinese alligator (Alligator sinensis). In addition, several extinct species of alligator are known from fossil remains. Are actually more closely related to birds than they are to lizards Molecular analysis, or genetic sequencing, of a 68-million-year-old Tyrannosaurus rex protein from the dinosaur's femur discovered in 2003 by paleontologist John Horner of the Museum of the Rockies confirms that T. rex shares a common ancestry with chickens, ostriches, and to a lesser extent, alligators. Order-Squamata • • • • • • • The fossil record of snakes is relatively poor because snake skeletons are typically small and fragile, making fossilization uncommon. The origin of snakes remains an unresolved issue. There are two main hypotheses competing for acceptance: Burrowing Lizard Hypothesis and Aquatic Mosasaur Hypothesis There is fossil evidence to suggest that snakes may have evolved from burrowing lizards, such as the varanids (or a similar group) during the Cretaceous Period.[14] An alternative hypothesis, based on morphology, suggests the ancestors of snakes were related to mosasaurs—extinct aquatic reptiles from the Cretaceous—which in turn are thought to have derived from varanid lizards.[12] Fossils readily identifiable as snakes (though often retaining hind limbs) first appear in the fossil record during the Cretaceous period.[10] These fossil sites have been tentatively dated to the Albian or Cenomanian age of the late Cretaceous, between 112 and 94 Ma ago. Based on comparative anatomy, there is consensus that snakes descended from lizards.[5]:11[12] Pythons and boas—primitive groups among modern snakes—have vestigial hind limbs: tiny, clawed digits known as anal spurs, which are used to grasp during mating.[5]:11[13] Birds – • • • • • • • • A close relationship between birds and dinosaurs was first proposed in the nineteenth century after the discovery of the primitive bird Archaeopteryx in Germany. Only a few scientists still debate the dinosaurian origin of birds, suggesting descent from other types of archosaurian reptiles. Theropods first appeared during the Carnian age of the late Triassic period about 230 million years ago (Ma) and included the sole large terrestrial carnivores from the Early Jurassic until at least the close of the Cretaceous, about 65 Ma. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by 9,900 living species. Among the features linking theropod dinosaurs to birds are the three-toed foot, a furcula (wishbone), air-filled bones, brooding of the eggs, and (in some cases) feathers. The ground-breaking discovery of fossilized Tyrannosaurus rex soft tissue allowed a molecular comparison of cellular anatomy and protein sequencing of collagen tissue, both of which demonstrated that T. rex and birds are more closely related to each other than either is to the alligator.[ Fossil evidence also demonstrates that birds and dinosaurs shared features such as hollow, pneumatized bones, gastroliths in the digestive system, nest-building and brooding behaviors. Modern birds are classified in Neornithes, which are now known to have evolved into some basic lineages by the end of the Cretaceous The Neornithes are split into the paleognaths and neognaths. Mammal Talking Points-General • • • • • • • • Although they came into their own only after the extinction of the dinosaurs some 65 million years ago, mammals had maintained a low-profile existence for some 150 million years before that. Descended from more archaic relatives, the early true mammals were mainly small insect-eating creatures adapted to nighttime activity. They ranged in size from scarcely bigger than a bumblebee to squirrel-sized, keeping out of the way of the predatory dinosaurs. They acquired certain traits that would characterize mammals ever afterward: limbs positioned under the body, an enlarged brain, a more complex physiology, milkproducing glands, and a diverse array of teeth -- incisors, canines, premolars, and molars. Already present were the ancestors of the three major mammalian groups that exist today -- monotremes (platypus and spiny anteater), which lay eggs externally; marsupials (kangaroos, opossums), which carry their young in a pouch; and placental mammals (humans, cows, horses), which retain the fetus internally during long gestation period. In the early Cenozoic era, after the dinosaurs became extinct, the number and diversity of mammals exploded. In just 10 million years -- a brief flash of time by geologic standards -- about 130 genera (groups of related species) had evolved, encompassing some 4,000 species. These included the first fully aquatic mammals (whales) and flying mammals (bats), as well as rodents and primates. This sudden expansion of species diversity into new ways of life is known as adaptive radiation. One way it occurs is in response to events that free up previously occupied environmental zones and roles, making way for many new species that adapt to these vacant living spaces. The extinction of the dinosaurs was one such major event, eliminating a once-dominant group of competitors while some mammals survived. It took several million years for the mammals to evolve even moderately large body sizes, and the world they inherited was a different place from the one the dinosaurs had dominated. There were new environmental habitats and new food resources to exploit. By the end of the Cretaceous, flowering plants had become dominant, providing food for burgeoning populations of insects, which in turn became another high-quality food source for the mammals, along with fruits and berries. New kinds of forests appeared, offering novel habitats for what would become tree-dwelling mammals -- primates, which first appeared about 50 million years ago, and eventually, some 45 million years later, upright-walking hominids, including us. The astonishing diversity of mammalian species today stems in part from the continuing breakup of the continents that began some 200 million years ago and sent different landmasses moving apart. Australia and South America were isolated from other continents during much of the Tertiary, and marsupial mammals thrived and diversified there, while placental mammals took over similar roles on the other continents. Order-Artiodactyla (Cetartiodactyla)-even toed ungulate • • • • • • • • • • • • This group includes pigs, peccaries, hippopotamuses, camels, chevrotains (mouse deer), deer, giraffes, pronghorn, antelopes, sheep, goats, and cattle. The group excludes whales even though DNA sequence data indicate that they share a common ancestor, making the group paraphyletic There are about 220 artiodactyl species, including many that are of great nutritional, economic, and cultural importance to humans. As with many mammal groups, even-toed ungulates first appeared during the Early Eocene (about 54 million years ago). By the Late Eocene (46 million years ago), the three modern suborders had already developed: Suina (the pig group); Tylopoda (the camel group); and Ruminantia (the goat and cattle group). artiodactyls were far from dominant at that time: the odd-toed ungulates (ancestors of today's horses and rhinos) were much more successful and far more numerous. Eventoed ungulates survived in niche roles, usually occupying marginal habitats, and it is presumably at that time that they developed their complex digestive systems, which allowed them to survive on lower-grade food. The appearance of grasses during the Eocene and their subsequent spread during the Miocene (about 20 million years ago) saw a major change; grasses are very difficult to eat and the even-toed ungulates with their highly-developed stomachs were better able to adapt to this coarse, low-nutrition diet, and soon replaced the odd-toed ungulates as the dominant terrestrial herbivores. Now-extinct Artiodactyla which developed during the Miocene include the genera Ampelomeryx, Tauromeryx, Triceromeryx and others. the first deer didn’t appear on the scene until about 25 mya after the early ungulates. the animals that many consider to be the precursors to deer -- animals such as Syndyoceras, which seems to share features with deer, horses, giraffes and antelopes - had bony skull outgrowths similar to non-deciduous antlers and were found in North America some 35 million years ago (mya), during the Miocene. Modern ‘true’ deer are thought to have evolved from ancestors similar to modern-day chevrotains at some point during the Oligocene (part of the mid-Tertiary, some 30 mya); they were small animals with simple antlers and large canine tusks that lived in the forests of the Old World tropics. All ungulate cetartiodactyls have pulley-shaped articulating surfaces on both ends of the astragalus (fossil evidence of cetaceans indicates that primitive whales also possessed this feature). The primary distinguishing feature of all of the ungulates within this order is the paraxonic limb structure, in which the symmetry of the foot passes between the two middle digits (III and IV). The first digit (the "thumb" or pollex in the hand and the hallux on the hind limb) is absent in all modern artiodactyls, with the result that all species possess an even number of toes on each foot Bison- Bison bison The biological subfamily Bovinae includes a diverse group of 10 genera of medium- to large-sized ungulates, including domestic cattle, the bison, African buffalo, the water buffalo, the yak, and the four-horned and spiral-horned antelopes. The evolutionary relationship between the members of the group is obscure, and their classification into loose tribes rather than formal subgroups reflects this uncertainty. General characteristics include cloven hoofs and usually at least one of the sexes of a species having true horns. FAMILY BOVIDAE • Subfamily Bovinae o Tribe Bovini • Genus Bison o American bison, Bison bison o Wisent, Bison bonasus o Steppe wisent†, Bison priscus (extinct) o Ancient bison†, Bison antiquus (extinct) o Long-horned bison†, Bison latifrons (extinct) During the Pleistocene Ice Age the ancestors of today’s Bison-bison, the Bison-priscus crossed from Siberia into Alaska. They descended from European Wisent. Bison-priscus evolved into Bison-latifrons and lived in North America for 300,000 years. 22,000 years ago, Bison-latifrons evolved into Bison-antiquus. 10,000 years ago Bison antiquus evolved into Bison-bison. White Tailed Deer-Odocoileus virginianus Family: Cervidae • It is believed that the white-tailed deer, or something similar first appeared in North America over 3 million years ago. • Fossil evidence of the genus odocoileus first appears in the Pliocene deposits in the central lowlands of NA (3.5-3.9 mya) • Odocoileus appeared as the climate cooled over North America. It occupied the warm southern lowlands. • This tolerance of warm climate characterizes the species to this day, even though it is cold hardy • The whitetail is the most widely distributed and abundant ungulate (hoofed mammal) in the western hemisphere • The graceful and adaptable White-tailed Deer is a strictly American species with no close relatives on other continents. • The many different subspecies or races of White-tailed Deer and the variations in their appearance, from the diminutive Key Deer of Florida to the large northern forms, suggests a long evolutionary history in the Americas. • Odocoileus crossed over the tropical Isthmus of Panama and colonized South America in the early Pleistocene along with other North American mammals at the beginning of the major glaciations Order Carnivora • The diverse order Carnivora includes over 280 species of placental mammals. • Carnivorans apparently evolved in North America out of members of the family Miacidae (miacids) about 42 million years ago. They soon split into cat-like and doglike forms • Miacids (Miacidae) were primitive carnivoramorphans that lived during the Paleocene and Eocene epochs, about 62–33 million years ago. Miacids existed for approximately 29 million years. • Miacids are thought to have evolved into the modern carnivorous mammals of the order Carnivora. They were small carnivores, superficially marten-like or civet-like with long, little bodies and long tails. Some species were arboreal, while others lived on the ground. • Carnivorans are the most diverse in size of any mammalian order, ranging from the least weasel (Mustela nivalis), at as little as 25 grams (0.88 oz) and 11 centimetres (4.3 in), to the polar bear (Ursus maritimus), which can weigh up to 1,000 kilograms (2,200 lb), to the southern elephant seal (Mirounga leonina), whose adult males weigh up to 5,000 kilograms (11,000 lb) and measure up to 6.9 metres (23 ft) in length. • The first vertebrate carnivores were fish, and then amphibians that moved on to land • Carnivora are generally divided into the suborders Feliformia (cat-like) and Caniformia (dog-like), the latter of which includes the pinnipeds. Piscivory was the diet of early tetrapods (amphibians); insectivory came next, then in time reptiles added herbivory.[1] Gray Wolf/ Fox-Order Carnivora • Many paleontologists strongly believe that the miacids are the most likely ancestors of the Canidae, which includes all wolves, dogs, and foxes • The miacids were a group of small early carnivores that evolved over 50 million years ago from primitive insectivores which lived alongside the dinosaurs during the Cretaceous Period. • The genus Canis is a rather recent development with some species such as the modern grey wolf having come about in the past one million years. • Other Canids, such as foxes, are older by comparison. The grey fox, Urocyon cinereogenteus is widely considered to be the most primitive canid alive today. • Grey woves Canis Lupus most likely originated in Asia. It most likely crossed the Pleistocene land bridge some 700,000 years ago. • The dire wolf, Canis dirus, a somewhat larger and more robust form of wolf had evolved in NA earlier. The dire wolf and the grey wolf shared the continent for nearly half a million years until the dire wolf died out in the great Pleistocene extinction of 16,000 years ago • The place of the red wolf Canis rufus in history of wolves is not yet very clear. Some believe it is not a true species but a hybridization of the grey wolf and the coyotes. Others theorize that it is a true species unique to NA which once had a wider distribution than it does today, but retreated southward as a result of grey wolf dispersion. o Suborder Caniformia ("dog-like") Family †Amphicyonidae: bear-dogs (9–37 mya) Family Canidae: dogs and allies; 37 species in 10 genera Infraorder Arctoidea Superfamily Ursoidea Family †Hemicyonidae: (2–22 mya) Family Ursidae: bears; 8 species in 5 genera Superfamily Musteloidea Family Ailuridae: red panda; 1 species in 1 genus. Family Mephitidae: skunks and stink badgers; 10 species in 4 genera Family Mustelidae: weasels, martens, badgers, wolverines, minks, ferrets, and otters; 55 species in 24 genera Family Procyonidae: raccoons and allies; 19 species in 6 genera Superfamily Pinnipedia Family †Enaliarctidae: (23–20 mya?) Family Odobenidae: walrus; 1 species in 1 genus Family Otariidae: sea lions, eared seals, fur seals; 14 species in 7 genera Family Phocidae: true seals; 19 species in 9 genera Bobcat Cougar Suborder Feliformia ("cat-like") Family †Stenoplesictidae Family †Percrocutidae Family †Nimravidae: false sabre-tooth cats (5–36 mya) Family Nandiniidae: African palm civet; 1 species in 1 genus Superfamily Feloidea Family Prinonodontidae: Asiatic linsangs; 2 species in 1 genus Family †Barbourofelidae (6–18 mya) Family Felidae: cats; 40 species in 14 genera Infraorder Viverroidea Family Viverridae: civets and allies; 35 species in 15 genera Superfamily Herpestoidea Family Hyaenidae: hyenas and aardwolf; 4 species in 4 genera Family Eupleridae: Malagasy carnivorans; 8 species in 7 genera Family Herpestidae: mongooses and allies; 33 species in 14 genera [1] FAMILY FELIDAE • • • • Genus Lynx [Lineage 5] Canadian Lynx (Lynx canadensis) Eurasian Lynx (Lynx lynx) Iberian Lynx (Lynx pardinus) Bobcat (Lynx rufus) Genus Puma [Lineage 6] Cougar (Puma concolor) Jaguarundi (Puma yagouaroundi) Extant felids belong to one of two subfamilies: Pantherinae (which includes the tiger, the lion, the jaguar, and the leopard), and Felinae (which includes the cougar, the cheetah, the lynxes, the ocelot, and the domestic cat). The first felids emerged during the Oligocene, about 25 million years ago. In prehistoric times, there was a third subfamily known as Machairodontinae, which included the "saber-toothed cats" such as the well known Smilodon. There are 41 known species of felids in the world today, all of which descended from the same ancestor.[1] This taxon originated in Asia and spread across continents by crossing land bridges. • ancient cats evolved into eight main lineages that diverged in the course of at least 10 migrations (in both directions) from continent to continent via the Bering land bridge and Isthmus of Panama,, with the Panthera genus being the oldest and the Felis genus being the youngest. They estimated that 60 percent of the modern species of cats developed within the last million years.[3] Armadillo-Dasypus novemcinctus Order CINGULATA • Family Dasypodidae odidae: armadillos o Subfamily Dasypodinae Genus Dasypus Tatus or Guinean Beast • • • • • Nine-banded armadillo or long-nosed nosed armadillo, Dasypus novemcinctus Seven-banded armadillo, Dasypus septemcinctus Southern long-nosed armadillo, Dasypus hybridus Llanos long-nosed armadillo, Dasypus sabanicola Great long-nosed armadillo, Dasypus kappleri Hairy long-nosed armadillo, Dasypus pilosus Yepes's mulita, Dasypus yepesi †Beautiful armadillo, Dasypus bellus The armadillo, which is considered to be an ancient and primitive species, is one of the only livingg remnants of the order Xenarthra. the closest relatives of the armadillo are sloths and anteaters, who also belong to the order Xenarthra The order first evolved around fifty million years ago, in what we now know as South America (Nixon, 1995) The armadillos that once roamed in South America, more than 10,000 years ago, were much bigger in size. It is said by researchers that once the corridor between North and South America emerged, large canine and feline predators migrated south and began to prey upon these giant armadillos (Stuart, 1986). This in turn contributed to the extinction and the migration of the giant armadillo (Dasypus bellus) out of South America towards North America. Migrating northward as far as the Ohio river valley, the armadillo armad survived for up to 10,000 years (Nixon, 1995). Sooner or later, for unknown reasons, • • • • • • • • • the armadillo became extinct in North America. Remarkably, a smaller version of the armadillo re-established themselves north of the Rio Grande. The nine-banded armadillo also serves science through its unusual reproductive system, in which four genetically identical offspring are born, the result of one original egg.[ This is the only reliable manifestation of polyembryony in the class Mammalia, and only exists within the genus Dasypus and not in all armadillos The nine-banded armadillo with a few close cousins are the only known creatures to give birth to same gender quadruplets (never more or less) from the same embryo. Even though the nine-banded armadillo produces one ovum per year, the development of polyembryony contributes to their massive reproduction rate (Watson, 1989). Implantation of the fertilized egg may be delayed for up to fourteen weeks after conception (Smith, 1984) and the gestation period is known to be 150 days or longer (Smith, 1984). The delay of the implantation of the embryo in the uterine wall is thought to be caused by stress (Watson, 1989). About 130 million years ago, South America was cut adrift from what is now the west African coast line of the super-continent of Gondwanaland. (1) This giant island raft of South America was thus successfully isolated from the rest of the world, as were the animals that lived there, during most of the period of mammal evolution. This was a time when many Mammals were evolving from smaller animals to a larger and more diversified group. Due to this extended period of geographic separation, which ended about three million years ago when the Americas touched, South America has produced some very unique plants and animals. This is where we meet the Xenarthrans. The group of mammals called the Xenathrans include sloth, anteaters, several extinct species and the armadillo. Xenathara is a small branch of mammals that first evolved around 50 million years ago. The earliest armadillo-like creatures were the glyptodon and the panocthus. These animals were quite large, about the size of a Volkswagen Beetle. They were also very heavily armored Isolated from the rest of the world, and protected from predators with their bony armor, the armadillos flourished. They were relatively safe from predation; that is, until a land bridge developed between North and South America. Large canine and feline predators moved southward along this bridge, wreaking havoc on the native South American animals. Fossil records show that around seventy percent of the indigenous South American mammals were destroyed. The armadillos were not immune to these new and larger predators — although their shells are made of bone, they are rather thin Opossum – Didelphis virginiana Order: Didelphimorphia Family: Didelphidae