Adaptions #4

Question 1

How are birds adapted

Answer 1

Forelimbs- adapted to produce lift and thrust
Feathers- shaped like aerofoil to increase lift
Large sternum- supporting huge muscles
Light weight skeleton with hollow bones

Question 2

How are terns adapted

Answer 2

Adapted for accurate diving

Question 3

How are hummingbirds adapted

Answer 3

Adapted for hovering

Question 4

What is the theory of adaption

Answer 4

Natural selection

Question 5

How does natural selection help explain adaption

Answer 5

• adaption is ‘undirected’
• results from differential survival of alternative alleles
• individuals with advantageous traits pass these onto offspring eventually these traits accumulate and these species become better adapted to their environment.

Question 6

What does an undirected adaption mean

Answer 6

Adaptions do not arise in response to a specific need or goal. Instead they result from random genetic mutations

Question 7

What are the alternative theories that accept adaption

Answer 7

Creationist and lamarcks

Question 8

Whats the problem with creationism and lamarcks theory with relation to adaption

Answer 8

They cannot explain it

Question 9

What other reasons other than natural selection are there for why traits change (adaptions)

Answer 9

Genetic drift- random changes especially in small groups
Mutations- random changes in DNA
Gene flow- New genes come in when individuals move between groups
Sexual selection- traits that help attract males even if they aren’t useful for survival

Question 10

What is genetic drift

Answer 10

Random change in the frequency of traits (genes) in a population especially a small one

Ie,
5 white and 5 brown fur rabbits. A storm kills 4 rabbits at random- 3 brown and 1 white. Not because white is better just because its by chance

Question 11

What is a mutation

Answer 11

Change in DNA of an organism can be helpful in leading to better traits (ie, disease resistance) or harmful and can cause problems

Question 12

Whats gene flow

Answer 12

Genes move from one population to another

Ie, a wolf from one pack migrates to a new pack and has pups. These pups can now carry genes from both packs

Question 13

Whats sexual selection

Answer 13

Type of natural selection where traits evolve because they help an individual attract a mate not just survive. These traits get passed on more often because they help an animal mates more

Question 14

Whats coadaption

Answer 14

When two or more traits evolve together in a way that makes them work better as a team

Ie,
In birds
- string chest muscles and long wings evolve together for better flying
In flowers
- bright colours and sweet nectar evolve together to attract pollinators

Question 15

Explain facts about the vertebrate eye in relation to coadaption

Answer 15

• 1% change per genetic mutation= very small improvement that build up over time
• 2,000 steps you’d get a highly complex organ like a modern invertebrate eye
• 400,000 years this would take at slow mutation rate

Question 16

What are disadvantageous stages

Answer 16

When a new body part is evolving it goes through early stages that aren’t perfect yet because they might not work very well or seem worse than what came before.

Ie,
Ancestor snakes had small legs at first smaller legs might have made moving harder. But as bodies became longer and better for slithering no legs was better

Early fish had fins for swimming but as they developed fins became bigger and were not good for land yet only for mud or low water which led to legs

Question 17

Whats preadaption

Answer 17

A trait that was evolved for one purpose but was later used for something else.

Ie,
birds Feathers used for warmth later used for flight

Question 18

Ray finned

Answer 18

Actinopterygii

Question 19

Lobe finned

Answer 19

Sarcopterygii

Question 20

Bony fishes

Answer 20

Osteichthyes

Question 21

Whats an exaptation

Answer 21

A trait that already exists and is reused for a completely new purpose. Multiple benefits

Ie, birds Feathers used feathers originally used for warmth but now used for flight as well

Question 22

What is pre-adaptation

Answer 22

A trait that developed for one job and was later used for a completely different purpose.

Ie,
Fish and fins later developed into legs for walking

Question 23

Whats the difference between
- adaptation
- preadaptation
- exaptation

Answer 23

Adaptation- a trait that has evolved specifically for its current job

Pre adaptation- a trait that has evolved for one job but later helped with a different one (ie, lobe finned fish used to have fins and now walk on land) change

Exaptation- a trait that already exists and is reused for a completely new purpose (ie, feathers in dinosaurs for warmth and used for flight) multiple benefits

Question 24

Whats a tetrapod

Answer 24

Animals with four limbs- amphibians, reptiles, birds and mammals

Question 25

Are all traits an adaption

Answer 25

No not all traits are adaptions. Adaptions evolve through natural selection to help survival or reproduction

Question 26

What makes a trait an adaption

Answer 26

It must be a trait that: - evolved through natural selection - gave an advantage in survival or reproduction - was passed onto future generations

Question 27

What is an example of a helpful trait thats not an adaption

Answer 27

Flying fish returning to the sea after gliding is helpful but is not an adaption. They never evolved to stay out of the sea so returning is just normal part of survival

Question 28

What are spandrels

Answer 28

Traits that exist as a by product of other adaptions not because they were directly selected for. Ie, Belly button - exists because of the umbilical cord which is essential during pregnancy (adaption) and the navel is just the leftover result (spandrel) Brain - brains evolved for language, problem solving and social reasoning. Math and reading are recent human inventions that we can do as a result of previous brain features

Question 29

Trait vs adaption

Answer 29

Trait-any feature of an organism (eye colour, migration or molecular) ie, having 5 fingers is a trait Adaption- specific kind of trait- must have evolved through natural selection because it gave a survival or reproductive advantage. Ie, webbed feet in ducks helps them swim

Question 30

What is the strongest effect of selection Group Organismal Cellular Genetic

Answer 30

Organismal

Question 31

Why aren’t adaptions perfect?

Answer 31

1. Natural selection works with what’s already there Ie, human spine evolved for walking on four legs not standing up right thats why we get back pain 2. Adaptions involve trade offs - a peacock tail attracts mates but makes it harder to escape predators 3. Historical factors - organisms can only evolve from what ancestors had. Evolution cant start from scratch 4. Developmental factors - humans cant grow extra limbs and insects can’t be very large. Some traits cant evolve even if they’d be useful because their bodies cant build them 5. Environment keeps changing - thick fur is great in cold but not when climate warms 6. Time constraints - climate change is happening faster than some animals can adapt 7. Genetic and developmental limits - we cant evolve wings like birds because our body plan doesn’t allow it

Question 32

What are neo-tropical anachronisms

Answer 32

A trait in an animal or plant that made sense in the past but no longer has a clear purpose today because the animal it co-evolved with is extinct Ie, avocado huge seed that no modern animal can easily swallow or disperse as it was evolved to be eaten by large extinct animals that could swallow it whole or poop it out after