Lecture 15 - Reptiles Flashcards
Explain Class : Reptilia
- Transition from water to land necessitated the ability to reproduce independent of water.
- Reptiles practise internal fertilization
- They lay eggs protected by leathery shell – amniotic egg
- Reptiles have horny epidermal scales
- Respiration by lungs with expandable rib cage, Except for turtles.
- Reptiles have 12 pairs of cranial nerves
Explain amniotic eggs fully
Amniotic egg contains extra-embryonic membranes for protection, excretion, Supply of oxygen, nutrients and water
Explain Class : Reptilia in more detail
- Protective skin prevents water loss
- Lungs are more developed than in amphibians;
- They have a four‑chambered heart, oxygen-rich blood is more fully separated from oxygen-poor blood.
- Well‑developed kidneys excrete uric acid; therefore, less water is lost in excretion.
- Reptiles are ectothermic.
- They are behaviorally adapted to warm their body temperature by sunbathing.
What are the orders of Class: Reptilia
- Order: Testudines (turtles and tortoises)
- Order: Squamata
- Order: Crocodylia (crocodiles and alligators)
What are the suborders of Class: Reptilia
- Suborder: Serpentes (snakes)
- Suborder: Sauria (lizards, skinks, chameleons, geckos)
Explain Order: Squamata
Suborder: Serpentes (snakes)
Suborder: Sauria (lizards, skinks, chameleons, geckos)
- Lizards have four clawed legs and are carnivorous.
- Marine iguanas on the Galapagos are adapted to spend long times in the sea.
- Chameleons live in trees.
- Snakes evolved from lizards and lost legs as an adaptation to burrowing.
- Their jaws can readily dislocate to engulf large food.
- A tongue collects airborne molecules to transfer them to Jacobson’s organ for tasting.
- Some snakes are poisonous and have special fangs to inject venom.
Explain The Komodo dragon
- Largest living lizard in the world. weigh about 154 pounds (70 kilograms)
- Males larger and bulkier than females.
- Their venom ishighly poisonous and enough to kill animals in a few hours, even humans
Explain crocodiles
- Oldest reptile
- Can hold its breath for 8 hours
- Powerful bite 3,700 pounds per square inch (psi)
- Can grow up to 7 meters long
- Live to 35 to 75 years
- Predator
Explain the evolution of reptiles
- The first reptiles (stem reptiles) gave rise to several lineages; each was adapted to a different way of life.
a. The pelycosaurs or sail lizards are related to therapsids, mammal like reptiles which are ancestral to mammals.
b. Some lineages returned to aquatic environments.
Dinosaurs varied in size and behavior; some had a bipedal stance and gave rise to birds.
Reptiles dominated earth for about 170 million years during the Mesozoic Era; then most died out.
Turtles and tortoises evolved first and are the oldest reptiles.
Crocodiles evolved after them.
Explain how Reptiles fully adapted to life on land
- Paired limbs
- Skin
- Efficient breathing
- Efficient circulation
- Efficient excretion
- Ectothermy
- Reproduction
Explain Class: Aves
- Birds, dinosaurs and crocodiles all belonged to a reptilian group called archosaurs.
- Only birds and crocodiles survive today
- Birds are the only modern animals with feathers
- Reptiles and birds share in common the amniotic egg, scales on their legs and the four chambered heart.
- Birds practice internal fertilization.
- They lay hard-shelled amniotic eggs
- They are endothermic- they produce their own body heat.
- Birds have a 4-chambered heart.
- Birds have hollow bones, air sacs and forelimbs(wings) that are adapted for flying
- They possess 12 pairs cranial nerves
Explain birds fully
- Birdshave a lightweightskeletonmade of mostly thin and hollow bones.
- The keel-shaped sternum (breastbone) is where the powerful flight muscles attach to the body.
- Birdshave a smaller total number of bones than mammals or reptiles.
- They have a powerful heart and unique lungs that supply oxygen to support the high metabolic rate to flight muscles.
- 9000 species of birds
- Lack teeth, and possess a only vestigial tail
- Scales on legs, claws on toes, horny beak
- Classification based on beak and foot types
- Birds are homeothermic- they are able to maintain a constant high body heat.
- Birds continue to be active when it is cold.
Explain how Birds adapted for flight
- They have feathers
- Feathers are modified reptilian scales
- Modified skeleton consisting of hollow bones
- Modified respiration because of specially adapted lungs. The lungs of birds do not inflate and deflate but rather retain a constant volume.
- Endothermy -produce their own body heat and homeothermy maintaining that body hat because of a high metabolism.
- Well developed sense organs and nervous system
- They can see as much as eight times better than we can
Explain Ostritches fully
- Largest flightless bird found only in Africa. An adult male may be 2.75 metres .
- Weighs more than 150 kg
- Lays the largest eggs. Length of an egg can be up to 15cm and weigh about 1,35 kg.
- Can run up to 70km per hour
- Unlike all other living birds, the ostrich secretes urine separately from feaces.
