formation of new species

Question 1

species

Answer 1

• a group of organisms closely related and able to breed among themselves

Question 2

population

Answer 2

• group of individuals of same species occupying the same habitat

Question 3

sexual reproduction

Answer 3

• meiosis : rearrangement of genetic material
• chance fertilization : female and male gamete recombines
• random mating : every male has a chance to mat with any other female

Question 4

mutations

Answer 4

• changes in base sequence of DNA

- deletion / duplication

Question 5

inbreeding

Answer 5

• mating of genetically closely related individuals
• loss of genetic diversity
• homozygosity
• desirable traits
• less vigour

Question 6

inbreeding depression

Answer 6

• animals : lower birth weight ; do not reproduce successfully ; less resistance to disease
• plants : less seeds ; poor seed germination

Question 7

outbreeding

Answer 7

• breeding of genetically unrelated individuals
• increase genetic variation
• heterozygosity
• desirable traits can be introduced
• removing undesirable traits

Question 8

inbreeding in humans

Answer 8

• mating of close relatives

- incest

Question 9

why is human inbreeding so frowned upon?

Answer 9

• carry the same mutation
• increased chance of harmful recessive alleles
• homozygous for recessive alleles
• eg. heamophilia ; Tay Sachs disease

Question 10

risks for homozygous genetic abnormality

Answer 10

• 1 in 20 for common ancestor
• 1 in 11 for first cousins
• 1 in 2 first degree relatives

Question 11

outbreeding

Answer 11

• increased heterozygosity in plants

Question 12

founder effect

Answer 12

• loss of genetic variation
• few individuals will have different gene pool to original population
• genetically and phenotypically different to parent population
• eg. Cheetah, fecundity : ability to produce abundant healthy offspring