Reptiles Flashcards
Where there any mammal marine predators at the time Mesozic marine reptiles where very succesfull (252-66 Ma)?
No
What is the Mesozic time also called
The time of the Dinasours
Did dinasours colinate the sea
NOoooooo, but marine reptiles did.
10-15 species, including turtles.
What are the advantages of ectothermic reptiles over endothermic?
More tolerant of low body temperatures
Their slow metabolism makes them able to hold their breath for longer.
They can tolerate anoxia (absence of oxygen) better when the O2 runs out.
What does Sauropterygia means, and how do they use them.
Lizard flippers. They move their tail up and down like modern whales.
Which are the two major lineages (groups) in the Sauropterygia, and what are their charecteristics.
Placodonts - short necks
- One group had body armour like a turtle.
- Other groups didn´t, but some had extra bones in the skin over the vertebrae.
- Geographically only found in one area.
Eosauropterygians - long necks with relatively small skulls.
- One group had long necks, and where slow swimmers. Perhaps catch smaller prey.
- the other group had shorter necks and were fast hunters.
- Geographically widespread.
At least one of the overall group gave birth to live young.
The evolution of the “flipper”
Through the evolution of the flipper, they kept the five digits, but extra phalanges (fingerbones) appeared. They became longer.
Same change mad the bones less flexible and the flipper more efficient.
What are the Ichtyyosaurs also called, and what are their characteristics?
Fish-lizard
Because its the only marine lizard who looks like a fish. Its tail moved side to side.
Wide ranges of body sizes
Really big eyes, for diving deep to catch food, where there is less light.
Pressure would deform their eyes, therfore they have a bone ring inside their eyes. They have flat eyes.
In the beginning their bones wouldn´t allow them to dive deep, so probarbly they lived close to the coast. Later they where able to dive deep and live in the open sea.
Gave birth to live young.
Many fingers evolved in this group, some species with 10 digits.
assumed to live in social group.
Had “blubber” like whales, witch help them to float.
Is tuataras lizards, and what are their characteristics?
No, they look like a lizard, but they beloung to another group.
Only one extant species in the world, which live on NZ.
Teeth are fused to the jawbone, which forms something which looks like a beak.
They have two rows of teeth, wow.
Temperature-dependent sex determination. Warmer weather equals more males.
What group is Sssssssquamata, characteristics?
Snakes and lizards, including Komodo.
Skin with horny scales or shields
Shed their skin, also lizards
Movable jaw bones, so thay can gac on something big.
Caudal autonomy, selfamputaion of the tail, as a defence mechanism. Some species are able to grow it back (months or years).
Sssssssquamata reproduction?
After reproduction, the female is kind of destroyed by the male spiky penis, which is smart in the way that the female will not mate after, because they are destroyed.
The attraction of females - Some have large skin flaps.
They fight for the best territories. Snakes do a kind of topping, which is the fight for putting the other male’s head down.
Partenogenesis - Eggs can develop and hatch without being fertilized. The female doesn´t meet a male.
Its a bad idea to have babies with yourself. Many of the young that hatch have birth problems, but for the female, it´s a defence mechanism.
Most species are oviparours
But some are viviparous or ovoviviparous
Who has venom and what does it do?
Lizards and snakes have venom. Its modified salvia glands.
One reptile can have different venoms.
- nervous system venom, neurotoxins.
- Circulatory venom, Haemotoxins
- Muscular venem, myotoxins
It’s an arms race, because the prey develops antivenom.
Normally they only inject the venom when, they wants to kill something. So normally in defence they will not inject the venom.
The antivenom sometime is worse, because maybe the snake didn´t inject the venom. Then you get something else in your system, who fucks things up.
Gekkota, characteristics
A gekko
Loud mating calls
like their eyeballs, because they dont have any eyelips to. Wihtout their eyes would dry out and get dirty.
Nocturnal species with excellent vision (incl. color)
Often lose their tail
Geko feet are miracoules. Can stick to almost any surface. Stickiness is created by hair on their feets. Changing the angles of their hairs will undo the stickiness
Inspire many biomimicry technologies, fx sticky tape.
Serpents
All kinds of snakes
Snake share a common ancestor with venomous lizards
Two theories
- They evolved from an aquatic reptiles.
- Most likely theory: The original snake was burrowing lizards.
One functional lung (strange inside organs placment)
mobile jaw
