Adaptations, Natural selection and Evolution

Question 1

What is population defined as?

Answer 1

A group of interbreeding organisms of the same species living in a particular niche in a habitat

Question 2

What do various populations make up?

Answer 2

A community

Question 3

Most resources needed for survival are in unlimited/limited supply? Therefore?

Answer 3

Limited supply. Therefore organisms must compete successfully

Question 4

What can a niche be defined as?

Answer 4

The way an organism exploits its environment

Question 5

All the species that share a habitat have different?

Answer 5

Niches

Question 6

What would happen if two species living in the same habitat had exactly the same role?

Answer 6

They will compete with each other, the better adapted organism will out-compete the other and exclude it from the habitat

Question 7

A successful species will be?

Answer 7

Well adapted to its niche

Question 8

features which enable organisms to survive are called?

Answer 8

Adaptations

Question 9

What three categories can adaptations be classified in?

Answer 9

Behavioural, physiological and anatomical

Question 10

Which adaptations are any actions by organisms which help them to survive or reproduce? (example)

Answer 10

Behavioural, agoutis bury brazil nuts - this will aid their survival by providing a future food source

Question 11

What are physiological adaptations?

Answer 11

features of the internal workings of organisms which help them to survive or reproduce e.g. whales are able to take in sea water and excrete the excess salt

Question 12

What are anatomical adaptations?

Answer 12

The structures we can see when we observe or dissect an organism e.g. the bodies of bumblebees show adaptations used to collect nectar and pollen

Question 13

What is co-adaptation?

Answer 13

When two species become dependent on each other and more closely adapted e.g. when the plant and its pollinator become so closely adapted as seen with bees tongues and petal tubes

Question 14

What is the struggle for existence?

Answer 14

As a population increases in size, a greater proportion of individuals will die or fail to reproduce due to competition for resources, disease and extreme environmental conditions

Question 15

What is differential survival called?

Answer 15

Survival of the fittest

Question 16

What is evolution precisely defined as?

Answer 16

A change in allele frequency in a population over time (generations)

Question 17

For natural selection to lead to evolution there…?

Answer 17

Must be some genetic variation in the population

Question 18

What is the definition for stabilising selection?

Answer 18

If the environment remains stable, then organisms may simply become better adapted to their existing niches, but if the environment changes then selection changes too

Question 19

The ability of a population to adapt to new conditions will depend on what three things?

Answer 19

1) The strength of the selection pressure
2) The size of the gene pool
3) The reproductive rate of the organism

Question 20

A gene pool consists of?

Answer 20

All the alleles of all the genes present in a population of a species at a given time

Question 21

What are populations with a bigger gene pool said to have?

Answer 21

Greater genetic diversity

Question 22

How may genetic diversity of a species decline?

Answer 22

When the population of a species too far, some alleles are lost, and the genetic diversity of the species declines

Question 23

Why is there no such thing as being ‘perfectly adapted’?

Answer 23

When the environment changes, there is a time lag before a population can adapt by natural selection, so organisms are always playing catch up

Question 24

The greater the variety of genotypes the greater the..?

Answer 24

Genetic diversity

Question 25

What is the direct way to measure genetic diversity?

Answer 25

DNA sequencing - determining which alleles are present