Formation of a new species

Question 1

Genetic engineering

Answer 1

the direct manipulation of the genes in an organism

Question 2

GMO (genetically modified organisms)

Answer 2

• the result of genetic engineering

- improve quality of life/productivity

Question 3

transgenic organism

Answer 3

-organism which genes have been altered using genetic engineering techniques

Question 4

recombinant DNA

Answer 4

DNA that contains foreign genes

Question 5

species

Answer 5

individuals with similar characteristics that can interbreed freely and produce fertile offspring

Question 6

Main causes of variation in a species

Answer 6

• crossing over and random assortment of homologous chromosomes pairs (meiosis)
• random fusion and random mating (reproduction) (greater genetic pool)
• mutations (gene and chromosome mutations)

Question 7

inbreeding

Answer 7

• crossing of closely related individuals

- promotes homozygosity

Question 8

advantages of inbreeding

Answer 8

• predictable offspring
• undesirable characteristics can be isolated
• recessive genes can be isolated

Question 9

1. disadvantages of inbreeding

Answer 9

• high mortality rate
• offspring have low resistance to diseases
• offspring can be sterile e.g. poor sperm quality
• decrease in frequency of heterozygous gene pairs

Question 10

2. disadvantages of inbreeding

Answer 10

• gene pool decreases (increases possibility of extinction)
• increase in abnormalities
• recessive genetic diseases (more evident)
• loss of vigour

Question 11

outbreeding

Answer 11

• crossing of unrelated individuals - offspring that is genetically diff
• promotes heterozygosity
• same species - diff breed

Question 12

advantages of outbreeding

Answer 12

• reintroduces lost characteristics
• individuals are still “pure”
• increases hybrid vigour in offspring
• new characteristics are introduced - genetic variation increases - gene pool enlarges

Question 13

disadvantages of outbreeding

Answer 13

• typical characteristics are lost
• loss of seperate race / breed - new races / breeds develop
• less predictability in offspring

Question 14

outbreeding

Answer 14

• crossing of unrelated individuals - offspring that is genetically diff
• promotes heterozygosity
• same species - diff breed

Question 15

advantages of outbreeding

Answer 15

• reintroduces lost characteristics
• individuals are still “pure”
• increases hybrid vigour in offspring
• new characteristics are introduced - genetic variation increases - gene pool enlarges

Question 16

disadvantages of outbreeding

Answer 16

• typical characteristics are lost
• loss of seperate race / breed - new races / breeds develop
• less predictability in offspring

Question 17

founder effect (deliberate isolation)

Answer 17

when a small fraction of the population moves away

Question 18

How does the founder effect work?

Answer 18

• starts with large population with different phenotypes
• small fraction of population moves away
• isolation - leads to inbreeding
• recessive allele is expressed in phenotype

Question 19

genetic bottle neck

Answer 19

animals

Question 20

speciation

Answer 20

formation of new species

Question 21

allopatric speciation

Answer 21

occurs when there is geographic isolation

Question 22

1. How allopatric speciation occurs?

Answer 22

• variation occurred in original population (name trait)
• population became separated by geographical barrier (name barrier)
• gene flow between the two populations stopped
• became reproductively isolated

Question 23

2. How allopatric speciation occurs?

Answer 23

• populations adopt separately to their environments
• the different environments exert different pressures (name them)
• over time mutations occur and they become genotypically and phenotypically different
• if two populations meet again, they won’t recognise each other - new species developed through allopatric speciation

Question 24

sympatric speciation

Answer 24

occurs when there is absence of a barrier

Question 25

1. How sympatric speciation occurs?

Answer 25

- occurs in the same geographical area (they become reproductively separated even though they occupy the same area) - moved away to avoid competition - population became separated (state the type of isolation) - gene flow between the two populations stopped

Question 26

2. How sympatric speciation occurs?

Answer 26

- became reproductively isolated - populations adopt separately to their environments - the different environments exert different pressures (name them) - over time mutations occur and they become genotypically and phenotypically different

Question 27

What can geographical isolation to?

Answer 27

It can lead to behavioural isolation over time

Question 28

Temporal isolation

Answer 28

breeding at different times of the year/day

Question 29

Ecological isolation

Answer 29

live in diff habitats in same environment and use diff resources

Question 30

Behavioural isolation

Answer 30

if courtship is unsuccessful, mating and fertilisation will not take place

Question 31

Mechanical isolation

Answer 31

the reproductive organs don't fit into each other - cannot reproduce

Question 32

Hybrid

Answer 32

hybrids are infertile