BIRDS

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BIRDS MAMMALS

• The platypus is a mosaic of mammalian, avian and
  reptilian traits.

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BIRDS MAMMALS

• EX The duck-billed platypus has a flat, fury
  tail that resembles a mammal, the beaver
  resembles turtles birds in that it has a
  cloaca, an enlarged duct through which faeces,
  excretions from the kidneys gametes pass.
• Female platypus has mammary glands but lays
  shelled eggs (Monotreme-an egg laying mammal), as
  turtles and birds do.
• Normally found in lagoons in Australia and
  Tasmania.

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BIRDS MAMMALS

• PLATYPUS

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BIRDS MAMMALS

• BIRDS
• The ability to fly evolved in four groups,
• Insects, pterosaurs (extinct), birds and bats
• Birds apparently evolved from reptiles during the
  Jurassic.
• 1. The oldest known bird (Archaeopteryx)
  resembled reptiles in limb bones and other
  features. (avian traits, including feathers).

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BIRDS AND MAMMALS

• Archaeopteryx

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BIRDS MAMMALS

• Pterosaur

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BIRDS MAMMALS

• 2. Birds still resemble reptiles
• horny beaks, scaly legs, and
• egg-laying.
• 3. There are greater than 9,000
• named species of birds. The
• smallest known birds weigh
• 2.25 gm (0.08 ounces), while
• the largest bird, the ostrich, weighs
• about 330 lbs.

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BIRDS MAMMALS

• AVIAN

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BIRDS MAMMALS

• 4. The first birds evolved from reptiles during
  the Mesozoic era. The feathers were a highly
• modified reptilian scale.

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BIRDS MAMMALS

• The body plan of birds is unique.
• 1. The body is covered with feathers
• helpful in flight and insulation.
• Elastic sacs connected to the
• lungs help dissipate excess heat
• as they force warmed air out of
• the body.

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BIRDS MAMMALS

• 2. Construction meets the requirements
• of flight low weight and high power.
• a. The bones are lightweight because
• of air cavities within them. There is a
• honey combed structure and an efficient
• mode of respiration and circulation.

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BIRDS MAMMALS

• b. Powerful muscles are attached
• at strategic places on the bones
• for maximum leverage.
• c. The heart is four-chambered,
• and the lungs are highly
• efficient because of their flow-
• through design.

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BIRDS MAMMALS

• AVIAN
• HEART

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BIRDS MAMMALS

• 3. Flight in general and migratory
• movements in particular are
• amazing feats that birds seem to
• accomplish with ease.
• FLIGHT PG 459 gives some explanation of the
  mechanics. Birds that are migratory move
  frequently from region to region in response to
  environmental rhythms. Seasonal change in day
  length is a cue, that influences internal timing
  mechanisms and biological clocks. Consequently,
  causes physiological and behavioral changes which
  induce birds to make round trips to different
  regions in different climates.

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BIRDS MAMMALS

• The Rise of Mammals
• Range from Kittis hog-nose bat 1.5 gm to 100
  ton
• whales
• Mammalian Traits
• 1. Brain capacity is increased, allowing
• more capacity for memory, learning, and
• conscious thought.

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BIRDS MAMMALS

• 2. Milk-secreting glands nourish the
  young.
• 3. Hair covers at least part of the
• body (whales are an exception).
• 4. Dentition is extensive and special-
• ized to meet dietary habits.

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BIRDS MAMMALS

• Other amniotes typically swallow their prey
  whole, but most mammals secure, cut and sometimes
  chew their food before swallowing it. Four
  distinctive types of upper and lower teeth serve
  this purpose incisors, canines, premolars, and
  molars.

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BIRDS MAMMALS

• The amniotes are a microphylum of tetrapod
  vertebrates that include the Synapsida (mammals)
  and Reptilia (reptiles and dinosaurs, including
  birds).

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BIRDS MAMMALS

• B. Mammalian Origins and Radiations
• 1. During the Triassic, divergence
• from the small, hairless reptiles
• called synapsids gave rise to the
• therapsids. The early ancestors
• of mammals.

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BIRDS MAMMALS

• Synapsids

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BIRDS MAMMALS

• 2. By Jurassic times, mouse-sized
• therians with jaws and hair had
• evolved. This was a diverse group
• of plant and meat eating mammals
• that co-existed with the dinosaurs.
• They began to flourish as the
• dinosaurs began to vanish.

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BIRDS MAMMALS

• 3. They (therians) had major changes
• in the jaws, teeth and body form.
• Their four limbs were positioned
• upright under the bodys trunk.
• It made it easier to walk upright.
• Stability however had not yet
• arrived. The cerebellum, the
• region of the brain, concerned with
• balance and spatial positioning
• was only beginning to expand.

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BIRDS MAMMALS

• 4. With the demise of the dinosaurs,
• diverse adaptive zones opened up
• for monotremes (egg-laying
• mammals), marsupials (pouched
• mammals), and eutherians
• (placental mammals).

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BIRDS MAMMALS

• Monotremes Spiny Anteaters (egg-laying)

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BIRDS MAMMALS

• Monotremes Duck-billed Platypus

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BIRDS MAMMALS

• Marsupials - kangaroos, koalas, wallabies,
  wombats, bandicoots, and opossums

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BIRDS MAMMALS

• Eutherians placental mammals

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BIRDS MAMMALS

• 5. Egg laying mammals Platypus/Spiny Anteater
• Compared with the monotremes and marsupials
  placental mammals had a competitive edge (i.e.,
  higher metabolic rates, more precise regulation
  of body temperature, and a new way of nourishing
  their developing embryos).

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BIRDS MAMMALS

• Existing Mammals
• Evolutionary distant, geographically isolated
  lineages often evolved in similar ways and in
  similar habitats and came to resemble each other
  in form and function.
• The lineages of mammals are examples
• of convergent evolution.

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BIRDS MAMMALS

• 1. The platypus and spiny anteater,
• which survive today in Australia,
• differ from other mammals in
• these ways
• a. They are practically toothless
• b. Metabolic rates are lower
• c. They lay eggs but suckle their
• young.

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BIRDS MAMMALS

• 2. The marsupials found in Australia
• and in North America are distinc-
• tive in that the young are born
• tiny, blind, and hairless but find
• their way to the mothers pouch
• where they are suckled and
• finish their development. 260
• species of marsupials are native
• to Australia. The Tasmanian devil
• the largest carnivorous marsupial.

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BIRDS MAMMALS

• 3. The descendants of therians, placental
  mammals are found in virtually every
  aquatic and terrestrial environment.
• a. The young are nourished within the
  mothers uterus by the placenta a composite
  of maternal and fetal tissue.
• b. It is the organ of exchange of oxygen,
  nutrients
• and wastes between the maternal blood and
• the fetal blood.

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BIRDS MAMMALS

• We have journeyed about 570 million years,
  starting from tiny bag like animals to craniates,
  from jawless and jawed fishes having a backbone.
  Arriving at the end of the Devonian era we saw
  the emergence of tetrapods, that possessed skull
  bones, jaws, a back bone, lungs, walking on four
  limbs that evolved from fleshy lobed fins, to
  amniotes reptiles and mammals to primates and
  then to humans.

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BIRDS MAMMALS

• Trends in Primate Evolution
• A. Primates include a wide variety of
• animals
• 1. Prosimians (literally before apes)
• are small tree dwellers (arboreal)
• that use their large eyes to advant-
• age during night hunting.

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BIRDS MAMMALS

• Prosimians Mongoose Lemur

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BIRDS MAMMALS

• 2. Tarsiers (tarsioids) are small
• primates with features inter-
• mediate between prosimians and
• anthropoids.
• 3. Anthropoids include monkeys, apes
• and humans. Hominoids include
  apes and humans, where Hominid refers to
  human lineages only.

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BIRDS MAMMALS

• Tarsiers Spectral Tarsier (S.E. Asia)

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BIRDS MAMMALS

• Anatomically and biochemically apes are closer to
  humans than monkeys, but chimps are most closely
  related.
• GA Tech conducted a genetic analysis of
  approximately 63 million base pairs of DNA 99.4

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BIRDS MAMMALS

• Ape and Man 98 -99 genetic similarity

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BIRDS MAMMALS

• Primate evolution displays key trends
• Five features set primates apart from other
  mammals
• 1. Less reliance on sense of smell and
• more on enhanced daytime vision
• a. Early primates had an eye on each
• side of the head.

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BIRDS MAMMALS

• b. Later ones had forward-directed
  eyes resulting in better depth
  perception and increased ability to
  discern shape, movement in three
• dimensions, color, and light intensity.

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BIRDS MAMMALS

• Apes - Forward-facing eyes for binocular vision
  (allowing depth perception) reliance on vision
  reduced noses, (smaller, flattened), color vision

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BIRDS MAMMALS

• 2. Skeletal modification promoted
• Bipedalism upright walking
• a. Bipedalism is possible because of
• of skeletal reorganization in
  primates ancestral to humans. This
  freed the bonds for novel tasks.

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BIRDS MAMMALS

• b. A monkey skeleton is suitable for
• a life of climbing, leaping, and
• running along tree branches with
• palms down.
• c. An ape skeleton is suitable for
• climbing and using the arms for
• carrying some body weight the
• shoulder blades allow the arms to
• swivel overhead.

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BIRDS MAMMALS

• d. Compared to the ape, humans
• have a shorter, S-shaped and
• somewhat flexible backbone.
• Skeletal change favoring
• bipedalism was a key innovation
• that evolved in ancestors of
• hominids.

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BIRDS MAMMALS

• 3. Bone and muscle changed led to
• refinements in hand movements.
• 4. Power grip and precision grip
• Early mammals spread their toes apart to
  support the body. Primates still spread fingers
  and toes. Tree-dwelling primates had
  modifications to handbones which allowed them to
  wrap their fingers around object.
• Prehensile Movement

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BIRDS MAMMALS

• a. Opposable thumb and fingers
• allowed more refined use of
• the hand.
• b. The precision and power grip
• movements of the human hand
• allowed for toolmaking.

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BIRDS MAMMALS

• 4. Teeth became less specialized.
• Jaws and teeth in early mammals
• suitable for eating insects and fruits
• and leaves later evolved long\ canines, in
  monkeys and apes and
• humans to rip flesh.
• 5. changes in the brain became inter-
• locked with changes in behavior and the
• evolution of culture.

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BIRDS MAMMALS

• 6. Brain, behavior, and culture
• is the sum of behavior patterns of
• a social group, passed on to
• generations through learning and
• symbolic behavior.
• a. Brain expansion and elaboration
• produced a brain of increased mass
• complexity, especially for thought,
• language, and conscious movements.

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BIRDS MAMMALS

• b. Human brain development promo-
• tion of new neural connections,
• led to patterns of human behavior
• known collectively as culture.
• Maternal core became intense
• and offspring started to acquire
• longer periods of dependency and
• learning.

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BIRDS MAMMALS

• From Early Primates to Hominids
• A. Origins and Early divergences
• 1. The first primates that evolved
• from mammals about 60 million
• years ago (Paleocene) resembled
• small rodents or tree shrews they had
• long snouts and were good foragers
• on the forest floor.

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BIRDS MAMMALS

• 2. By the Eocene, their descendants
• were living in trees, had larger
• brains, were active in the daytime,
• and possessed better grasping
• movements. Trees offered a
• larger quantity of food and safety
• from ground-dwelling predators.

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BIRDS MAMMALS

• 3. By the time of the Oligocene,
• tree-dwelling ancestors of monkeys
• and apes, such as the anthropoid
• Catopithecus, had emerged.
• 4. The first hominoids ape-like forms
• appeared between 23 and 5 million
• years ago (Miocene)

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BIRDS MAMMALS

• They evolved and spread through Asia, Africa and
  Europe. During this time too, shifts in land
  masses and ocean circulation caused long-terms
  change climate.
• The First Hominids
• 1. Most of the earliest known
• hominids lived in the East African
• Rift Valley.

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BIRDS MAMMALS

• a. Cooler and drier weather in this
• region of the world encouraged
• the transition of hominids to
• mixed woodlands and grasslands.
• Food eventually became more
• scarce. Hominoids had two choices,
• move to adaptive zones or die.
• Those who moved survived those
• who did not more became extinct. The
• lineage of the former became the first
• hominids while the latter game rise to the
• great apes.

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BIRDS MAMMALS

• b. The plasticity of early hominids
• was the result of the capacity to
• learn to adapt.
• 2. The first known hominids are
  designated australopiths (southern
• apes).

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BIRDS MAMMALS

• a. The oldest has been designated
• Australopithecus anamenis other forms have
  been designated Australopithecus afarensis and
  A. africanus.
• b. More robust muscular heavily built
• were A. boisei and A. robustus.

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BIRDS MAMMALS

• c. Relationship of these species is
  uncertain, but all shared several
  characteristics improved dentition for
  grinding harder foods, upright walking,
  bipedalism (leaving footprints), and
  increased manual dexterity.

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BIRDS MAMMALS

• Ape vs. Human Fossils
• Ape-like feature Hominid feature
• Jaw shape rectangular dentation U-shaped
  dentation
• Spine shape straight S-shaped
• Posture knuckle-walked erect posture, bipedal
• Pelvis elongated short
• Supraorbital pronounced ridges not pronounced
• Plane of face projected forward flat faced
• Teeth larger, large canines smaller, smaller
  canines

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BIRDS MAMMALS

• Emergence of Early Humans
• Modern humans emerged from the traits seen in
  our tree-dwelling ancestors, relying more on the
  acute daytime vision than sense of smell.
  Manipulative skills increased. Bipedalism,
  omnivorous eating habits and increased brain
  complexity and behavior.

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BIRDS MAMMALS

• A. Which traits characterized humans?
• 1. Human is mostly defined by the
  increased brain capacity which allows
• analytical skills, complex social
  behavior, and technological innovation.
  These set us apart from apes.
• 2. The earliest human is designated Homo
  habilis, signifying handy man

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BIRDS MAMMALS

• B. Homo habilis is associated with the
  first stone tools.
• 1. hominids began to use stone tools
  about 2.5 million years ago to get marrow out
  of bone to scrape flesh from bones
• 2. Manufactured tools have been
  found at Olduvai Gorge.

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BIRDS MAMMALS

• Emergence of Modern Humans
• A. How did Homo erectus become Homo sapiens?
• 1. H. erectus migrated out of Africa
  into Europe and Asia.
• 2. Selection pressures triggered adaptive
  radiations resulting in physical changes
  as well as cultural shifts.

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BIRDS MAMMALS

• Comparison between

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BIRDS MAMMALS

• a. Homo erectus had a longer, chinless
  face, thick-walled skull, heavy browridge
  but narrow- hipped and long-legged.
• b. Homo erectus made advanced stone
  tools and used fired as they migrated out
  of Africa into Asia and Europe.

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BIRDS MAMMALS

• B. By about 100,000 years ago, Homo sapiens had
  evolved from Homo erectus
• 1. Early H. sapiens had smaller teeth, a
  chin, thinner facial bones, larger
  brain, and rounder, higher skull.
• 2. Neanderthals were similar to modern
  humans but disappeared about 35,000
  years ago.

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BIRDS MAMMALS

• 3. From about 40,000 years ago to
  today, human evolution has been cultural,
  not biological.