Subphylum Vertebrata
A vertebrate is a “cephalized,
sensate, bilaterally
symmetrical, motile,
coelomate gnathostome
having a segmented
endoskeleton, a dorsal hollow
nerve cord, and a ventral gut.”
(p. 119, Ostram)
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Vertebrates, Reproduction in Birds, Monotremes, Marsupials, and Placental Mammals, Slides of Biology
Detailed information about various aspects of vertebrate anatomy and reproduction. It covers classes of vertebrates such as birds, monotremes, marsupials, and placental mammals, discussing their characteristics, egg production, embryonic development, and feeding methods. Students of biology, zoology, or related fields may find this document useful for understanding the diversity of vertebrate life.
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2012/2013
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Download Vertebrates, Reproduction in Birds, Monotremes, Marsupials, and Placental Mammals and more Slides Biology in PDF only on Docsity!
Subphylum Vertebrata
A vertebrate is a “cephalized,
sensate, bilaterally
symmetrical, motile,
coelomate gnathostome
having a segmented
endoskeleton, a dorsal hollow
nerve cord, and a ventral gut.”
(p. 119, Ostram)
Class Aves – Birds
Have feathers Have forelimbs modified as wings Have a horny bill made of keratin (feathers and hair are also made of keratin) Have no teeth (reduces weight) Grind their food in a gizzard (since no teeth— seen also in dinosaurs) Have certain reduced or absent organs (reduces weight) Have ultra-light bones (reduces weight) Have acute vision (e.g., high-speed tree-branch avoidance) Have larger brains (high-speed 3-D computation) Are bipedal (as were dinosaurs)
Marsupial Reproduction
“Both the marsupials' ovaries produce eggs, and they have a double womb. Once fertilised, the egg spends between 12 and 28 days in the womb, feeding from a yolk sac and absorbing nutrients secreted by the womb lining. The youngster is then born in an embryonic state, with only the front limbs developed. It attaches to one of the females' nipples, which are often surrounded by a protective flap of skin forming a pouch. The teat swells slightly in the youngster's mouth so that it stays firmly in place, and there it stays, growing… Marsupial mothers put very little into producing their youngsters at first, and can quite easily expel them from the pouch if they are pursued by a predator or conditions become difficult… ”
Placental Reproduction
“Placental mammals have a single womb
into which eggs are shed from both ovaries.
Once fertilised, the egg remains in the womb
and a placenta develops. This organ allows
the embryo's and the mother's blood to pass
so close to each other (without mixing) that
nutrients and oxygen can pass to the
developing youngster from the mother and
she can absorb its waste products. Some
marsupials have developed a simplified version of the placenta that allows them to keep the embryos inside their body for longer than other marsupials, but the placental mammals have developed it to extremes and so their young can be born almost fully formed. Their size is only limited by the fact that they have to pass through the mother's pelvis to be born.”
Anthropoids (Monkeys, etc.)
Particularly relative to Prosimians, Monkeys (and descendants)…
Are diurnal ( daylight )
Have color vision ( color )
Have opposable thumbs ( thumbs )
Have expanded brains ( smart )
Have extended child development ( childhood )
Have complex social structures ( clans )
Knuckle Walking
A way to be a
primarily
terrestrail
quadraped,
have large (i.e.,
heavy) bodies,
and have
hands, all at
the same time!
Homo habilis
- H. habilis descended from an australopithecine (or nearly australopithecine-like) ancestor
- Along with H. rudolfensis , H. habilis thus represents the origin of the genus Homo
- H. habilis means “Handy Man” and these Hominins are among the first obligate tool users
- We speculate that H. habilis was much more of meat eater than the ancestral australopithecine
- H. habilis had relatively larger brain, and brains are very expensive tissue to build and maintain
- Perhaps a diet that consisted of meat was necessary for having a large brain
- Perhaps a larger brain also made it easier to acquire meat (e.g., via the use of tools)
- H. habilis may have been more meat scavenger (e.g., stealing from leopards) than hunter
Homo erectus
- H. erectus lived from approximately 1.8 to 0. million years ago and perhaps even longer
- H. erectus was the most successful of the the genus Homo lineages in terms of time on Earth
- H. erectus lived in large groups, controlled fire, and had a much more sophisticated tool kit than previous Hominins
- H. erectus spread her kind throughout the old world
Human Classificiation
-^ Domain Eucarya - Kingdom Animalia - Phylum Chordata - Subphylum Vertebrata (same clade as below?) - Amniota ≈ Class Reptilia - Synapsida (not Anapsida or Diapsida) - Mammal-like reptiles (same as above?) - Class Mammalia (synapsids with hair and milk) - Monotremes (if defined as clade including eutherians; is such a clade equivalent to class mammalia?) - Marsupials (if defined as clade including eutherians) - Eutherian (placental) mammals - Non Afrotheria (elephants, etc.) mammals - Non order-Edentata (S. American) mammals - Hypothetical Rodent, Raddit, Tree Shrew, Primate Clade - Order Primata (the primates)
Human Classificiation
-^ Order Primata (the primates) - Prosimians (equivalent cladistically to primates?) - Suborder Anthropoidea (the monkeys) - Superfamily Hominoidea (the apes) - Family Hominidae (formerly upright-walking apes but now the apes less the gibbons) - Sub-family Homininae (the African apes; I.e., the extant apes less the gibbons and the orangutans) - Hominini (upright-walking apes) - Genus Australopithecus (equivalent cladistically to Hominini?) - Genus Homo - Homo habilis (and others) - Homo erectus - Homo sapiens archaic - Homo sapiens sapiens (our species & subspecies)