reptiles juju
TRANSCRIPT
Reptiles
Julian Martinez
What is a reptile?• A reptile is a
vertebrate that has dry, scaly skin, lungs, and terrestrial eggs with several membranes.
• These allow the reptile to live it’s whole life out of water.
Evolution
• Evolved from amphibian-like ancestors• After the Carboniferous Period, lakes
and swamps dried up, which reduced some available habitat for water-dependent amphibians.
Mammal-like Reptiles
• Mixture of reptilian and mammalian characteristics
• Eventually came to dominate many land habitats
• During the Triassic Period (215 million years ago) Dinosaurs dominated.
Enter the Dinosaurs
• Ranged in sizes from small to enormous!
• Some ran on two legs or lumbered on four.
• All dinosaurs belonged to 1 of 2 groups– Ornithischia (Bird-Hipped)– Saurischia (Lizard-Hipped)
Exit the Dinosaurs
• At the end of the Crustaceous Period (65 mill. Years ago) mass extinction occurred.
• Multiple natural disasters– Volcanic eruptions and lava flows,
the dropping of sea level, and a huge asteroid or comet hitting what is now the Yucatán Peninsula in Mexico.
– Caused huge forest fires and dust storms ridding of the dinosaurs
Form and Function
• Well-developed lungs; a double-loop circulatory system; strong limbs; internal fertilization; and shelled, terrestrial eggs are the other adoptions that have contributed to the success of reptiles on land.
Body Temperature Control
• Reptiles control their body temperature by moving locations.
• To warm up, they bask in the sun during the day or stay underwater at night
• To stay cool, they move to the shade or go swimming, or take shelter in underground burrows.
• Ectotherms: An animal that relies on interactions with the environment to help it control body temp.– Turtles and snakes
Feeding
• Wide range of foods• Most animals eat insects.• Carnivores– Snakes- small animals and
bird eggs– Crocs/Alligators- fish and
land animals• Herbivores– Iguanas- tears plants and
swallows the chunks
Respiration
• Many reptiles have muscles around their ribs that expand the chest cavity to force air out.
• Snakes only have 1 lung.• Spongy lungs– Providing more gas
exchange area than amphibians
Circulation
• The alligator and crocodile have the most developed hearts– 2 atria and 2 ventricles
• Reptile hearts have 2 atria and 1 or 2 ventricles
• Double loop circulatory system– One brings blood to and
from the lungs– Brings blood to and from
the rest of the body
Excretion
• Urine produced in the kidneys• Reptiles’ urine contains ammonia or uric acid• Crocs and alligators consume a lot of water,
which dilutes the ammonia in the urine and carries it away.
• Land animals convert the ammonia into uric acid.– Less toxic than ammonia
Response
• A reptile’s brain is smaller than that of an amphibian.
• Day active animals have better vision than others.
• Snakes have a great sense of smell because of their lack of eyesight.
• Reptiles have 2 sensory organs at the top of their mouths the detect chemicals when reptiles flick their tongues.
Movement
• Reptiles with legs have stronger, larger limbs that enable them to walk, run, swim, burrow, or climb.
Reproduction
• Internal fertilization• Reptiles lay eggs.• Most reptiles have penis-like
organs that deliver sperm to the female’s cloaca.
• Some snakes and lizards are ovoviviparous
Groups of Reptiles
• The four surviving groups of reptiles are snakes and lizards, crocodilians, turtles and tortoises, and the tuatara.
Lizards and Snakes
• Modern lizards and snakes belong to the order squamata, which means “scaly reptiles”
• Lizards– Legs– Clawed toes– External ears– Movable eyelids
Crocodilians
• Fierce carnivores that feed on other animals.
• Very protective over their young
• The females guard the eggs and carries them to a nursery area and watches over them.
• Only found in tropics, or subtropics where climate remains warm all year
Turtles and Tortoises
• Belong the order Testudines
• Have shells built in their skeletons
• Shell consists of 2 parts– Carapace- the part of the
exoskeleton that covers the cephalothorax.
– Plastron- Ventral part of the shell
Tuataras
• Surviving member of the order Sphenodonta• Found only on a few islands off the coast of
New Zealand• Lack external ears and retain primitive scales
Ecology
• Endangered species • Habitat being destroyed• Humans hunt reptiles
for food, to sell as pets, and for their skin.
• Sea turtle recovery programs– Help babies get a head
start on survival