Unit 3: Evolution

Question 1

What are the supporting theory for evolution by Anatomy?

Answer 1

Mammals, for example, have very similar internal anatomies which implies that we all came from one common ancestor.

Question 2

What is the supporting theory for evolution by fossils?

Answer 2

Fossils provide a record for how species have evolved as we can see how one species has changed over large amounts of time.

Question 3

what is the supporting theory for evolution based by direct observation?

Answer 3

We can see animals that have evolved slightly different traits to better adapt to their environment. For example some birds might be the same size and shape as another but they have different coloured feathers as those feathers might be better suited to the place they live.

Question 4

Why do species often adaptations in their genetics?

Answer 4

Species get adaptations because they could have mutated a trait which makes them more suited for their environment.
For example
giraffes slowly over time evolved different length heads because shrubbery was being eaten by smaller animals. This made it so that only giraffes with long necks would have food to eat, meaning only giraffes with long heads could mate as they were the only ones that were alive.

Question 5

what is a vestigial stucture?

Answer 5

A part of an organism that was once useful but is now useless.

Question 6

Analogous Structures Vs. Homologous Structure?

Answer 6

Homologous Structure:
A structure in two organisms that is similar in appearance but different in function. For example all these bones serve different functions but derive from the same structure.
Analogous Structure:
A feature in two organisms that is similar in function but does not derive from one common ancestor. An example of this would be flight in bats and birds.

Question 7

Artifical Selection Vs. Natural Selection

Answer 7

Natural Selection:
When nature decides whether or not a trait is desirable or not. For example nature will kill off birds who can not fly, or people who are too stupid to use their god damn blinkers.
Artificial Selection:
When factors other than natural select what species get to breed. For example in ancient Egypt dog racing was a big sport so dogs who could run the fastest would get more food and would be able to breed more so the Egyptians would have even faster dogs.

Question 8

What are the 5 mechanisms for microevolution?

Answer 8

Mutations
Sexual Selection
Natural Selection
Gene Flow
Genetic Drift

Question 9

What are Mutations?

Answer 9

Species mutate traits that are beneficial to their survival and that trait gets passed down. Examples include sickle cell anaemia.

Question 10

What is difference between Natural and Sexual Selection?

Answer 10

Sexual Selection
When one gender of a species chooses to mate with only specific members who they see fit.
Natural Selection
When nature determines traits that are unideal by killing off organisms that do not have those traits.

Question 11

What is Gene Flow and Genetic Drift?

Answer 11

Gene Flow
When organisms from one location mate with organisms from another population. Ex: Someone from France has a kid with someone from Vietnam.
Genetics Drift
the type of evolution formulated complety by chance blc of some unforseen event

Question 12

What is Directional Selection?

Answer 12

favours the phenotypes at one extreme over the other
Directional selection is most common either when
a population’s environment changes, members of a population migrate to a new habitat with different environmental conditions than their former one

Question 13

What is Stabilizing Selection?

Answer 13

• acts against extreme phenotypes and favours intermediate variants
  This type of selection reduces variation and maintains the status quo for a particular phenotypic characteristic

Question 14

What is Disruptive Selection

Answer 14

when the conditions favour the extreme types over the intermediate

Question 15

What is Micro evolution?

Answer 15

a quick change in a species givenm the composition

Question 16

What is sexual selection?

Answer 16

natural mating selection and success, where others have a higher chance of getting a mate than others

Question 17

What is sexual dimorsphism?

Answer 17

marked differences between sexes in secondary sexual characteristics, not directly associated with reproduction

Question 18

What is the difference between geographic and habitat isolation?

Answer 18

Geographical:
species kept from each other through physical barriers for a long eneough that they become different species
Habitat:
2 species that occupy different habitats within the same area may encounter, even though there are no physical barriers

Question 19

What is the difference between Prezyotic and Postzyotic Barriers?

Answer 19

Prezoytic
Hinder the fertilization if memebers of different species try to mate
Post Zygotic
they prevent the hybrid zygote from developping into a good fertile adult

Question 20

What is the difference between temporal and behavioral isolation?

Answer 20

Temporal:
species that breed during different times of year, seasons, day
can not mix their gametes
Behavioral:
courtship rituals that attract mates are effectuve barriers

Question 21

What is the difference between Mechanical and Gametic isolation?

Answer 21

Mechanical:
morphological differences can prevent successful mating
like with genetical openings
Gametic:
Sperm may not be able to fertilze the eggs of another species

Question 22

What are some Postzygotic Barriers?

Answer 22

Reduced hybrid viabiltliy: the genes of different parent species may interact and impair the offspring’s developpment
Hybrid Streility:
if the chromosomes of the parents species differ in number of stucture, this may lead meiosis to fail to produce normal gametes of the hybrid
Hybrid Breakdown:
if the hybrid is fertile, their offspring can be feeble or sterile