Week 3 - amphibian diversity and adaptions Flashcards
Why does Australia have a large diversity of amphibians?
Australia has exerted a selection pressure on the selection of frogs - why we have a large diversity of frogs in australia (particular in breeding)
water is responsibility for amphibian diversity.
Describe the major anatomical features that distinguish the amniotic egg from
the anamniotic egg including cosst/benefits of this reproductive strategy
Although both providing protection for the embryo. The major anatomical features that distinguish the amniotic egg from is anamniotic egg are amniotes egg are laid on land, or the fertilized egg within the mother’s body and are not permeable skin,
Where as an anamniotic egg is laid in water, lack the amnion and embryonic membrane produced during the fetal development allows for permeable the exchanged of water and gases through the skin
Advantages to amniotic eggs
1. enables embryos to develop faster and larger before hatching
2. free animals dependency on bodies of water for reproduction and larval stage
3. reduces competition for pools of water in which larvae can mature
4. Avoids predation on larvae by aquatic predators.
Achieved by foam nests, mouth/stomach/ vocal sac brooding, and direct development
Costs
1. metabolically expensive
2. requires very specific environments
Describe convergent features turtles share with other lineages occupying the
same niche and what the evolutionary shaping pressures were
solutions to the same problems, animals look like turtles but they are not.
Elongation of ribs - becoming the turtle shell. Started as a burrowing animals, protecting itself from predation - eventually becoming more semi aquatic.
Beak of turtle
Distinguish between Cryptodira and Pleurodira tutles
Cryptodira
Neck folds in mid-sagittal
plane during head
retraction
Sea turtles, pig-nosed and soft shell freshwater turtles,
land tortoises all over the world
Pleurodira side-necked turtles
Confined to southern hemisphere
Dominant freshwater species in
Australia
Fold neck to side under shell
for protection
Describe cloacal breathing and costs/benefits of this unique respiratory
strategy
Cloacal breathing is the ability for the turtle to exchange gases through the cloaca (ventilated). Acts as a gill, enabling large amount of oxygen from the water to be absorbed. respired.
Costs - increase of water pollution can inhibit the amount of oxygen taken in, warmer waters means less oxygen available.
Benefits - high amounts of oxygen is taken in, assists in fast moving actions and longer dives for the turtle.
fritzroy river turtle family Pleurondira
Describe how suction feedingworks and what predatory strategy uses this
Suction feeding is found amoung long necked turtles such as Australian Pleurodira turtles. The water and prey are drawn into the mouth via expansion of mouth and pharyngeal cavity. It collapses allowing a suction to occur.
Describe niche partitioning between sea turtle species and within life stages
of some species
Sea turtles species have highly specialised characteristics, therefore a high degree of habitat partitioning.
males do no attend to land, both females and males breed in water and females return to land to lay eggs on land.
Green turtles - facilitates scraping algae off rocks and sea grass with specialised serrations and beaks - maintaining coral reefs.
Loggerhead sea turtles - eating crabs, conchs whelks and horseshoe crabs - long head enables them to achieve this
Hawksbill sea turtle - crevice feeding eaching spongivores as they have a specialised diet and are resistant to associated toxins.
Olive ridley sea turtle - generalist sea turtle - wide variety of animals and plants.
Kemps ridley sea turtle - generalist carnivore - fish , crabs, jellies, shrimp and molluscs.
Flat back sea turtle - omnivore consumes sea cucumbers, jellies, soft corals
Describe the unique adaptations leatherback sea turtles have for specialising
upon jellyfish and why this makes them so vulnerable to plastic bags
They have unique structures within their mouths to prevent jellyfish from escaping outside the mouth. They are spines within the mouth and they have two sharp pointed cusps - one upper and one on the lower jaw allows them to pieces jellies. They are attracted to eating jellyfish, therefore, plastics bags that resemble jellyfish get eaten - and because of these structures in place, cannot regret the contents eaten.
Describe different egg dipause and hatching strategies and how this benefits a
particular niche but comes with unique costs
Australian Pleurodira turtles -
Broad-shelled river turtles lay their eggs in the autumn/winter when the soil temperature is dropping and there is inactivity of monitor lizards. The embryos begin to develop but enter a secondary diapause stage in early development. The warming of the soil in spring and summer breaks the dipause and development continues.
How do female frogs discriminate from their species male calls?
Females discriminate their species’ male calls by:
Spectral attributes:
§ Fundamental frequency (vocal cords)
§ Harmonic content
§ Dominant frequency (resonance of cavities)
§ Frequency modulation (muscular)
Temporal attributes:
§ Duration
§ Pulse repetition rate (PRR), Call repetition rate (CRR)
§ Amplitude modulation
