Vertebrate Movement to Land
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Transcript of Vertebrate Movement to Land
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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- imperfect 4)Ectothermic Paired limbs with five toes and clawsTough, dry, scaly skin (horny epidermal scales)
Jaws adapted for crushing and grippingBreathe with lungsmetanephric kidney- produces uric acid to reduce water loss Large 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 and gas exchange.
• 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 ancestordichotomous key
• Elongated massive skull• Imperfect 4 chambered heart• crocodiles, alligators, and caimans, gavials
Phylum ChordataSubphylum VertebrataClass Reptilia
Order Crocodilia
CrocodiliansCrocodiles, Alligators,
Caimans, & Gavials
Gavial(gharial)
Carnivores, “ghara”- pot- bulb on snout12.25- 15.5 ft. longRivers of India, Nepal, Pakistan, Bhutan, BangladeshCritically Endangered
Alligator
Crocodile
Largest, best predatosLive in/near Salt waterAmerican Crocodile- EndangeredMost in Australia
CaimanRivers/swamps of Central and South America3ft- 16 ft. (only in black caiman species)
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
• If the temperature is above 34ºC - males.
• If the temperature is in between- young of both sexes.
Land Adaptations for Reptiles• Legs underneath bodies (tetrapods)• Lungs • more efficient circulatory system• Scales- prevents dehydration, protection• Claws• Amniotic egg• The excretory waste of the reptiles is uric acid
unlike the dilute, water wasting ammonia in the urine of Amphibians