vertebrate diversity 2

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vertebrate diversity 2
2011-12-09 17:55:53
vertebrate diversity

vertebrate diversity 2
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  1. Amphibians
    • Includes frogs, toads, salamanders, and caecilians
    • Two stages in lifecycle
    • Begin life adapted to an aquatic
    • environment (e.g., tadpoles have gills)
    • Mature into semi-terrestrial adults with
    • lungs
    • Most adults respire through lungs and
    • moist skin
    • Most have four limbs

  2. Amphibian Reproduction
    • They reproduce sexually using external
    • fertilization
    • The male sperm swim to the female eggs
    • Eggs are protected from drying by a jelly-like coating
    • Larvae, such as the tadpoles of some
    • frogs and toads, develop in water

  3. Amphibians Require Water
    • Their skin must be kept moist to avoid
    • desiccation when out of water
    • Lungs do not provide enough oxygen, skin supplements O2 via diffusion
    • Their breeding behavior and use of
    • external fertilization requires water
    • Sperm must swim to eggs

  4. Amphibian Groups
    • Frogs and toads undergo metamorphosis
    • from aquatic tadpoles into terrestrial adults
    • Salamanders have lizard-like bodies with
    • four legs and a long tail
    • Begin as aquatic larvae with gills that
    • may be retained in adulthood
    • others metamorphose into terrestrial
    • adults
    • Caecilians are limbless burrowing
    • amphibians
    • they have small eyes and limited vision

  5. Vertebrates: Reptiles
    • Evolved from an amphibian ancestor about
    • 250 million years ago
    • Reptiles include lizards, snakes,
    • alligators, crocodiles, turtles, birds
    • They respire exclusively through lungs

  6. Reptile Adaptations to Land
    • “Improvements” over their amphibian
    • ancestors
    • Tough scaly skin that resists water loss
    • Internal fertilization
    • Three- or four-chambered hearts
    • separates oxygenated and deoxygenated
    • blood more effectively
    • More efficient lungs than amphibians
    • Do not use skin as a respiratory organn
    • Shelled, amniotic egg
    • Protects the embryo in a liquid-filled
    • membrane, or amnion
    • Allows reptiles to live away from water
    • Skeleton provides better support and more
    • efficient movement on land than do those of amphibians

  7. Snakes and Lizards
    • Both groups mostly predators
    • Adaptations of snakes to predatory lifestyle
    • Special sense organs that track prey by sensing body temperature
    • Some have venom that is delivered through hollow teeth
    • Snakes have a jaw joint that permits the snake to swallow prey
    • much larger than its hea
    • Lizards are generally small, eat insects or inverts
    • Some can be large, e.g. Komodo dragon

  8. Crocodiles and Alligators
    • Aquatic, warm waters
    • Nostrils on top of head permit breathing while submerged
    • Strong jaws, pointed teeth for crushing and tearing prey
    • Extensive parental care (within reptiles this is unique to crocs)
  9. Turtles
    • Occupy many habitats
    • Box-like shell that is fused to the vertebrae, ribs, collarbone
    • No teeth- use beak to eat plants or animals
    • Leatherback turtle is the largest
    • Some have long migratory routes for
    • nesting

  10. Birds
    • Appear in the fossil record 150 million years ago
    • Distinguished from other reptiles by feathers, which are highly specialized reptilian scales
    • Modern birds retain scales on their legs, which is evidence of
    • evolution from common reptile ancestor
    • The earliest known bird is Archaeopteryx (~150mya)

  11. Adaptations for Flight
    • Feathers provide lift, control, insulation
    • Hollow bones reduce the weight of the skeleton
    • Bird reproductive organs shrink considerably during non-breeding periods
    • Females have a single ovary
    • The nervous system provides coordination and balance for flight, acute eyesight

  12. Mammals
    • Appeared in fossil record
    • ~250 mya
    • They did not diversify and dominate terrestrial habitats until the dinosaurs became extinct (~65 mya)
    • Produce milk from mammary glands
    • Endothermic with high metabolic rates
    • Four-chambered heart
    • Most have hair that protects and insulates
    • Most have limbs for running rather than crawling
    • They have sweat, scent, and sebaceous
    • (oil-producing) glands, which are not found in other vertebrates

    • The mammalian brain is highly developed
    • Mammals have unparalleled curiosity and
    • learning ability, allowing them to alter their behavior based on experience
    • This increases their chances of survival in a changing environment
    • Mammals have extended parental care after birth
    • This allows some mammals to learn extensively through parental guidance

  13. Mammal Groups
    • Monotremes
    • Egg-laying mammals
    • Marsupials
    • Embryos develop in protective pouch
    • Placental mammals
    • Embryos develop in uterus where they are
    • nourished by a placenta

  14. Montromenes
    • Includes only three species
    • Platypuses forage for food in the water and eat
    • small vertebrate and invertebrate animals
    • Echidnas (anteaters, 2 species) are
    • terrestrial and eat insects and worms they dig out of the ground
    • All lay leathery eggs rather than giving birth to live young
    • The newly hatched young are nourished from milk secreted by the mother

  15. Marsupials
    • Includes the opossums, koalas, kangaroos, wallabies, wombats, and the Tasmania devil
    • Embryos begin development in the uterus of the female
    • Gestations may be only a few weeks
    • Young are born at a very immature stage and must crawl to pouch to nurse
    • Some species spend a year or more in the pouch

  16. Placental Mammals
    • Ubiquitous
    • Diverse group including such animals as bats, moles, whales, seals, primates, etc.
    • Rodents account form almost 40% of all mammal species
    • Uterus contains a placenta that
    • functions in gas, nutrient, and waste exchange between mother
    • and embryo(s)
    • Young are retained in the uterus for their entire embryonic development

  17. Bats: Flying Mammals
    • Adaptations for feeding on specific foods such as nectar, fruits, insects
    • Most are predators and hunt frogs, fish, flying insects, or blood that they obtain from the skin of sleeping mammals or birds
    • Echolocation to catch flying prey
    • Wings are adapted “hands”