alana and annasimone. timeline 47 million years ago: - alligator like feet - fed in the water - 4.1...
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Evolution of Whales Alana and Annasimone
Timeline47 million years
ago:- Alligator like
feet- Fed in the water - 4.1 metres long - Forelimbs and hind limbs for
walking- No tail flukes
48 million years ago:
- 1.75 metres long - Nostrils were far
forward - Forelimbs and
hindlimbs function for walking
- No tail flukes
46 million years ago:
- Sea lion figure - Spent some time
on land- 3 metres long
- function for walking and swimming
- Large hind limbs - No tail flukes
37 million years ago: - Completely aquatic
- 4.5 metres long - Nostrils further back
on skull - Forelimbs have become flippers
- Elongation of the trunk
- Reduced hind limbs- Tail flukes
Present day: - Streamlined body - Insultating layer of
blubber - Flippers as fore
limbs - Hind legs are
interbal vestiges - Tail is flattended horixontal flukes
- No external neck - Large head and wide
mouth
34 million years ago: - Completely aquatic - 9-10 metres long
- Teeth reduced - First evidence of baleen for filter
feeding - Nostrils further
back on skull- Elbows immobile
Since whales evolved from land mammals, at first their nostrils were positioned far forward.
At one point, a mutation occurred, producing at least one whale with “nostrils” positioned further back along the snout.
Nostrils Nostrils
This mutation helped that whale thrive in a sea environment by easing the process of surfacing for air.
The mutated whale survived, thrived and reproduced, passing on this favourable characteristic to its offspring.
This mutation became more common among the population
Modern whales are now born with “nostrils” (blowholes) on their backs
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