Populations and conservation

Question 1

Define niche

Answer 1

Describes how an organism ‘fits’ into an ecosystem and its role in that environment.

Question 2

What is an adaptation?

Answer 2

A feature of an organism that increases its chance of survival in its environment

Question 3

Describe the three types of adaptation

Answer 3

Anatomical, physiological, behavioral

Question 4

What is the Hardy-Weinberg equation used for?

Answer 4

It’s used to determine whether there is a change in allele frequency over time in a population.

Question 5

What is the Hardy-Weinberg equation?

Answer 5

p2+ 2pq + q2=1
p2= frequency of homozygous dominant
2pq= frequency of heterozygous
q2= frequency of homozygous recessive

Question 6

What causes a change in allele frequencies over time?

Answer 6

Mutations in genes which cause natural selection can cause a change in allele frequencies over time as selectively advantageous alleles become more common

Question 7

Why does natural selection occur?

What factors contribute to it

Answer 7

Predation, disease, competition. All result in different survival and reproduction.

Question 8

What is evolution?

Answer 8

Change in allele frequency in gene pool of a population. Results in development of new dominant characteristics.

Question 9

How does natural selection lead to evolution?

Answer 9

-Random mutations result in new alleles.
-Some alleles provide an advantage for the individual
-Offspring receive new allele & frequency increases over many generations. Frequency of unfavorable alleles decreases.

Question 10

Define speciation

Answer 10

When a population is split and reproductively isolated, there are different selective pressures on the two groups. If the genetic makeup changes to the extent that the two groups can’t breed anymore, they have become separate species.

Question 11

What is meant by allopatric speciation?

Answer 11

Speciation resulting from a physical barrier (river, mountain range). The environments occupied by the two groups are different, so different alleles are favored.

Question 12

What is sympatric speciation?

Answer 12

Speciation resulting from a non-physical barrier e.g. a mutation that no longer allows 2 organisms to produce offspring. Any changes in anatomy or behavior may also prevent breeding.

Question 13

What is conservation?

Answer 13

The maintenance of ecosystems and biodiversity by humans in order to preserve Earth’s resources.

Question 14

Describe what is meant by an endangered species

Answer 14

A species that, due to a loss of habitat or rapid decrease in population numbers, is at risk of extinction.

Question 15

How can conservation be achieved?

What measures can be taken

Answer 15

Seed banks, gene and sperm banks, species reintroduction, protection of habitats, protection of endangered species, international cooperation.

Question 16

Why is the conservation of gene pools important?

Answer 16

● Many plant species are yet to be discovered and may contain chemicals that could be used in future medicines
● Protection of potential future food sources
● Some alleles may provide selective advantages, preventing extinction
● Each species and its genes are precious

Question 17

What is in-situ conservation?

Answer 17

Conservation of organisms and the surrounding area within their natural habitat using methods like protected habitats.

Question 18

What are the advantages of in-situ conservation?

Answer 18

-The whole habitat and environment can be conserved.
-Organisms can interact with their natural environment and occupy their appropriate ecological niche.
-Typically cheaper than ex-situ conservation sites.
-More organisms can be conserved at the same time

Question 19

What are the disadvantages of in-situ conservation?

Answer 19

• Conservation may be harder as certain factors
  which were threatening the populations are likely to still be present
• It is often difficult to devote large portions of land to conservation where land is needed for growing
  populations

Question 20

What is ex-situ conservation?

Answer 20

Conservation of organisms away from their natural habitats like in zoos or seed banks.

Question 21

What are the advantages of ex-situ conservation methods?

Answer 21

-Predation and natural threats to the population are eliminated
-Some sites can bring money from tourism to help cover costs.
-They can be used for education.
-The health of organisms can be monitored closely
-Scientific investigations are much easier as there are fewer uncontrolled variables

Question 22

What are the disadvantages of ex-situ conservation methods?

Answer 22

• Reintroduction into their natural habitat may be difficult as the animals will not be used to the environment and may be less likely to survive
• Genetic diversity will be significantly lowered in captive populations
• Ex-situ sites are expensive to establish and maintain
• Animals may behave differently which might make breeding programmes difficult