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56 Cards in this Set

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Name some examples of extreme adaptations of Spadefoot toad.
American spadefoot toads - hibernation in dry environments in 1 m depth under the ground from late August to early July. When the rain falls, arise. Urinary bladder stores water, water is absorbed from soil when buried, urea stored in tissues, can lose 40% of their body water. Tadpoles are omnivorous when conditions are good, cannibalistic when the food supply is low.
Name some examples of extreme adaptations of Xenopus.
Aquatic toad, but can migrate on land when the conditions are not good. Can aestivate for 6 months in mud or dried ponds. Can survive without food for a year. Metabolism slows to conserve energy. Olfaction adoption to sense smells in air and water, eyes can see in air, has lateral line system. Maintain territories in water, have good memory. As defences use toxins, anti-bacterial secretions. Can tolerate 4 to 28 degrees temp.
What is the advantage of having distinct larval and adult forms?
It can help to avoid intraspecific competition (tadpoles are omnivorous or herbivorous, adults - only carnivorous).
What is the difference between the eggs of reptiles, birds and amphibians?
Amphibians have shell-less eggs; Reptiles have leathery and flexible amniotic eggs;
Birds have calcareous amniotic eggs.
Do animals heaching out of amniotic egg always have no larval stage?
Yes.
How many embryonic membranes does amniotic egg have?
Four.
Name membranes and their functions of amniotic egg.
1. Amnion - protection.
2. Chorion - exchange of gases between embryo and the air.
3.Allantois - storage of nitrogenous vastes.
4. Yolk sac - nutrient supply by blood.
Label.
What are the disadvantages of amniotic egg?
Must have internal fertilisation;
Looses heat rapidly;
Requires more parental care;
Expensive to produce (fewer eggs produced by one individual).
What are anapsids?
Parareptiles + turtles. An anapsid is an amniote whose skull does not have openings near the temples.
Class: Reptilia
Subclass: Anapsida.
How are early amniotes distinguished in the fossil record?
By the opening in the skull (fenestra). Anapsids - no openings, synapsids - one opening, diapsids - two openings.
What are parapsids?
Large extinct creatures, stocky quadrupeds, had plates on skin, died ab. 200 mya.
What are the name of two protective shells of turtles?
Bottom shell - plastron, upper shell - carapace.
What are chelonians and what two types are they divided into?
They are turtles. Divided into:
Cryptodires: hidden neck turtle - neck retracts in S shape into the shell, most turtles.
Pleurodires - side-necked turtles - neck folds sideways, but does not retract into shell, few species.
All living reptiles, except turtles, are: anapsids/diapsids/synapsids (chose one).
Diapsids.
Name two linages of diapsids that are still present (two are extinct: plesiosaurs, Ichthyosaurs).
Lepidosaurs (lizards and snakes) and Archosaurs (crocodilians, birds, dinasaurs).
Name two living lineages of Lepidosaurs.
Tuataras and Squamata.
What is the largest group of non-avian reptiles?
Lepidosaurs.
In which group of diapsids secondary loss of limbs is common?
Lepidosaurs.
Describe Tuatara (lepidosaurs, diapsids).
Lizard-like, but the skull is heavier.
Nocturnal, and live in cool habitats, low body temperate compared to most lizards.
Live in burrows that they may share with seabirds.
Dependent on seabirds for food (directly, and indirectly – eat arthropods attracted by guano).
Temperature-dependent sex determination.
 Slow reproduction (reach maturity after 10-20 years), breed once every 4 years, embryos take 11-14 months to hatch.
Describe Squamata (lepidosaurs, diapsids - lizards, snakes).
8000 sp. Size 16mm to 3m. Highly kinetic skulls, scaly skin, legs lost multiple times during evolution in legless forms.
What two living clades do archosaurs include?
Crocodilians and birds (Also pterosaurs + non-avian dinosaurs, but extinct).
How many species of crocodilians are extant?
23 species.
Name three crocodilian families.
Crocodylidae, alligatoridae, gavialidae.
Why do all crocodilians swallow stones?
To act as a ballast and aid prey digestion.
Briefly describe digestive system of crocodilians.
They have two stomachs, the first one muscular to ground prey, the second acidic, can digest bones, horn, feathers.
What are amniotes?
Monophyletoc group that is a sister clade the living amphibians. Amniotes include the living reptiles, birds, mammals. Their primary feature is a presence of amniotic egg. This is the major advance on the traditional amphibian lifestyle.
Name two basal lineages of amniotes.
Mammals and reptiles.
Name two basic lineages of reptiles (...sids).
Anapsids (parapsids and turtles) and diapsids.
Fill in blanks.
Name four orders of extant reptiles.
Chelonia, squamata, tuatara, crocodila.
Describe respiratory adaptations of reptiles.
All reptiles posessel lungs and they do not go through larval stage, so do not have gills at any point of their life.
In snakes the left lung is lacking or reduced in size as adaptation to a long body shape.
Ventilation by rib movements (in turtles muscle movements, so lungs move forward and back, not on the sides).
In some species body parts can be used for gas exchange.
Describe thermal regulation of reptiles.
Ectotherms. Can regulate their metabolic heat (heat derived from oxidation of food and from other processes) for production of sustained body heat warmth and constant body temperature.
What are the benefits of being ectothermic? And what is the main disadvantage?
Variable body temperature allows animal to survive on low food input. Leads to slow metabolic rate (10% of birds and mammals).
The reproduction is very slow, so can risk with extinction because of overharvest.
What is the adaptation of amphibians to cold environments?
They evolve cryoprotectants (antifreeze proteins) to avoid freezing.
What is the adaptation of reptiles to prevent water loss?
Nitrogenous waste is excreted as uric acid;
body covered with horny scales,
skin provides a barrier for water loss.
Describe locomotion (and body shapes that help locomotion) of reptiles.
Limbs and girdles that support the body from underneath (so no sprawling gait). Many reptiles have bipedal walking and running (eg basilisk).
Flaps of skin between elongated ribs allows gliding in some lizards.
Webbed feet allows geckos to 'fly' acting like a parachute.
Leglessness in snakes allows burrowing, efficient movement, and coiling.
Swimming snakes have flattened tails.
Describe snakes movement method of lateral undulation.
Lateral undulation: movements left and right coupled with posterior moving waves push against contact points in the environment, such as rocks, twigs, irregularities in the soil. Most common form of movement.
Describe snakes movement method of sidewinding.
Sidewinding: a modified lateral undulation, and good where solid contact points are absent. Different parts of the body touch the substrate at different times.
Describe snakes movement method of concertina.
Concertina: used in tunnels. Latter half of body grips the tunnel wall, while anterior stretches, and then vice-versa.
Describe snakes' rectilinear movement method.
No lateral movement. Belly scales are lifted and pulled forward before being placed down and the body pulled over them. Used by large pythons and boas.
Explain how geckos can walk on walls.
There are special setae on the surface of geckos feet. Adhesion between tips of setae and substrate linked to van der Waal’s forces (electrical intermolecular attractions).
How can crocodilians to hold prey in jaws without water entering the
respiratory tract?
Crocodiles have secondary palate (shelf in roof of mouth separates nasal and mouth passages).
What is the predatory adaptation of crocodilians that they use to detect prey on the water and in the darkness?
Dermal pressure receptors, bundles of nerve fibres that respond to slight disturbance in surface waters.
Why do snakes stick their tongue in and out?
Snake tongue collects odour particles, then withdraws.
• Transfers particles into olfactory chamber - processed by the Jacobsons’s organ.
• Sensitive to compounds with high molecular weight.
Which organs do snakes use for sensing prey (olfaction)?
Generally use nostrils (olfaction) for long-range, and Jacobson’s organ (vomerolfaction) for shortrange sensing.
What other rather unusual sensor system is used in snakes to detect endothermic prey?
 Certain snakes (e.g. pit vipers, some boas, some pythons) can detect minute changes in the infrared spectrum (heat). Pit organs are located in ‘pits’ in the skin, between the nostril and eye. Detect prey, even if standing still.
Describe the action of venom of snakes.
 Some venoms are neurotoxic (death after paralysis of respiratory muscles);
 Others haemolytic (breakdown of blood cells), some act on cell membrane function.
 Most venoms contain both, with one predominating.
What methods do reptiles use for predator avoidance?
Mainly camouflage, shed tails, mimicry (mimic venomous snakes).
Which gene has role in melanin production in reptiles?
Mc I r gene.
When did dinosaurs first evolve?
Dinosaurs (part of the Ornithodira) first evolved during the Triassic, alongside the Crurotarsi.
Name two dinosaur clades that survived end-Triassic mass extinctions (distinguished by the pectoral girdle) and shortly describe them.
i) Ornithischia (‘bird hipped croppers’). All were erbivorous, and it includes variety of four legged and bipedal species. They were rare prior to the Jurassic, but reasonably common thereafter.
ii) Saurischia (‘lizard hipped dinosaurs’) contains two major lineages the bipedal carnivores (Theropods) and the quadrapedal long-necked herbivores (Sauropodomorphs).
Name three hypothesis about thermoregunation of dinosaurs.
- Endothermic
- ectothermic
- inertial homeothermy (maintain body temp., but that temperature depends on mass, larger indiv., smaller surface area).
How long ago did dinosaurs went extinct?
65 MYA.
What are the only living representatives of the dinosaurs?
Birds (therapod lineage).
Name two the most plausible suggestions for the reason of extinction of the dinosaurs 65 MYA.
1. Meteor impact. This likely to have led to a sudden drop in temperatures, followed by a prolonged cool period.
2. Deccan traps. Series of massive volcanic eruptions in India, that could affect climate. Dust and aerosols could have blocked sunlight and reduced photosynthesis.