Download 9 grade biology 1 Qt Trail Talking Points Evolutionary History/History

9th grade biology
1 Qt Trail Talking Points
Evolutionary History/History of Life and Classification of Kingdoms
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Photosynthetic Organisms
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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
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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:
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mosses &
liverworts.
Bryophytes: Mosses and Liverworts
Bryophytes, most commonly represented by mosses have the following characteristics:
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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)
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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 •
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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
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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.
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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
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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:
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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)
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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:
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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:
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naked-seed plants (such as conifers), known as gymnosperms and
flowering plants, the angiosperms.
flowering plants may be divided into the
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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.
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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.
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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.
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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)
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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)
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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)
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Cartilaginous fish, better known as sharks, skates, and rays evolved during the
Silurian period.
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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)
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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)
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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]
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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)
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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:
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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
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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
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Gopherus
o Gopherus agassizii, Mojave Desert Tortoise, Agassiz's Desert Tortoise
o Gopherus berlandieri, Texas Tortoise, Berlandier's Tortoise
o Gopherus flavomarginatus, Bolson Tortoise
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Gopherus morafkai, Sonoran Desert Tortoise, Morajak's Desert Tortoise
Gopherus polyphemus, Gopher Tortoise
Order-Crocodilia
Family - Alligatoridae
American Alligator
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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
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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 –
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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
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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
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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
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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.
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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
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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.
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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
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Family Dasypodidae
odidae: armadillos
o Subfamily Dasypodinae
Genus Dasypus
Tatus or Guinean Beast
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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,
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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