Post on 22-Feb-2016
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Vertebrate Movement to LandSZ2- Students will explain
evolutionary history of animals over the history of life on earth.
• Tetrapods- Animals with 4 limbs– Amphibians– Reptiles– Birds– Mammals
• Evolved from fish
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Transition from Sea to Land
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•Coelacanth
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Eusthenopteron
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Panderichthys
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Tiktaalik
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Transitional TetrapodsSkull, teeth, limbs similar to lobe-
finned fish
IchthyostegaAcanthostega
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Amphibians
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Adaptations to live on land
• Gills are usually lost• Lungs function• Breathe through skin• Secrete mucus – Prevent dehydration– Aids in respiration
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More Adaptations to live on land
• Skeleton – Fins evolve into limbs– Vertebral column
supports body underneath it
AIR IS NOT AS BOUYANT AS WATER.
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Evolution of CirculationFish Amphibian
Kingdom AnimaliaPhylum ChordataSubphylum VertebrataClass Amphibia1st land vertebrates Ex: frogs, toads, & salamanders
Class Amphibia – “Double Life”frogs, toads, salamanders, & newts
Characteristics• “Double Life” -lives part of
its life in water and part on land
• Ectothermic- “outside heat”- body temp. regulated by environment
• no scales or claws• Have thin, moist skin
Egg- tadpole- adult• larvae are herbivores, adults carnivores • larva have tails to move in water• external fertilization with no parental care• lay eggs without shells in water
AMPHIBIAN METAMORPHOSIS
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• Amphibian Body Plan– Bilateral symmetry– 3 chambered heart– Larvae breathe through gills; adults breathe
through lungs– Breathe through thin, moist skin (produces
mucus)– Changes from larva to adult through
the process of metamorphosis
Class AmphibiaOrder Anura
• Anura- an=without, ura= tail• Tailless• Hindlegs adapted for jumping and swimming• Tympanum (ear drum) and larynx well
developedEx. Frogs and toadsfrog dissection intro-http://www.kiz-oyunlari.com/files/file/kurbaga_ameliyat.swf
Class AmphibiaOrder Caudata
• Caudata- “have a tail”• Long tail• 2 pairs of limbsEx. Salamanders and newts
Class Amphibia:Order Gymnophiona(Apoda)
Gymnos- nakedophis- snake
live in tropicsElongated bodyLimblesscarnivores
Ex. Caecilians – “blind”-small eyes
Kingdom AnimaliaPhylum ChordataClass Reptilia
Ex: snake, turtle, lizards crocodile, dinosaurs
Reptilian Traits:3 chambered heart (except for crocodilians-4)Ectothermic endo vs. ectoPaired limbs with five toes and clawsTough, dry, scaly skin (horny epidermal scales)
Jaws adapted for crushing and grippingBreathe with lungsSolid nitrogen wastes - due to metanephredic kidneyLarge cerebrum as compared to rest if brain-
behaviors- 1. instinct 2. learned
Reptile Legs• Short tetrapods for
walking• Positioning of the
legs more directly under the animal. This position provided more support than the splayed arrangement of the Amphibian legs.
Reproduction:Internal fertilization (to avoid desiccation of
gametes), oviparousLay amniotic eggs on land- no dependence on
waterShells leathery, sometimes calcareous
Amniotic Egg Structures & Functions• Chorion provides a special hard covering that is permeable
to respiratory gases (O2 and CO2) while being impermeable to water vapor.
• Allantois is a storage reservoir for metabolic waste products such as nitrogenous compounds.
• Amnion is a fluid filled sac that acts as a cushion for the embryo and also prevents desiccation.
• Yolk sac contains food for the embryo, thus eliminating the need for a larval stage.
Phylum ChordataSubphylum Vertebrata
Class ReptiliaOrder Testudine:
Body in a bony case -dorsal carapace(top of shell) - ventral plastron(bottom of shell)Jaws with a horny beak, no teethVertebrae and ribs fusedEx. Turtles and tortoises
Turtle Shell Anatomy
Fusion of ribs, vertebrae, & carapace
Turtle Life Cycle
Phylum ChordataSubphylum VertebrataClass ReptiliaOrder Sphenodonta
• Primitive reptile• closely related to dinosaur• Looks like lizard• Diapsid skullEx. Tuatara- only living species
Phylum ChordataSubphylum VertebrataClass Reptilia
Order SquamataDiapsid skull with two temporal openings
Skin is shed with horny epidermal scales
Jacobson’s organ- sense of smell
Movable skin, kinetic skull
Poisonous- hemotoxins (blood) , neurotoxins(nervous system)
EX. Snakes and lizards
Lizards have movable eyelidsSnakes- descended from tetrapod ancestor
• Elongated massive skull• True, 4 chambered heart• crocodiles, alligators, and caimans
Phylum ChordataSubphylum VertebrataClass Reptilia
Order Crocodilia
CrocodiliansCrocodiles, Alligators,
Caimans, & Gavials
Gavial
Alligator
Crocodile
Caiman
Crocodilian Reproduction
• The temperature inside the nest of several crocodilian species decides the sex of the young. ~50-80 eggs
• If the nest temperature is 30ºC, females will hatch from all the eggs
• If the temperature is above 34ºC, all will be males.
• If the temperature is in between, there will be young of both sexes.
Land Adaptations for Reptiles
• Legs (tetrapods)• Lungs and more efficient circulatory system• Scales• Claws• Amniotic egg• The excretory waste of the reptiles is uric acid
unlike the dilute, water wasting ammonia in the urine of Amphibians