Genetics and populations and ecosystem

Question 1

autosomal linkage

Answer 1

when one or more genes are positioned on the same autosome and are unlikely to separate or independently assort (written as (FG)(fg))

Question 2

sex linkage

Answer 2

gees that are found on a region f sex chromosomes that is not present on the other sex chromosome (3 female geno. and 2 male geno.)

Question 3

co dominance

Answer 3

when both alleles are dominant and can be expressed

Question 4

epistasis

Answer 4

two genes on separate chromosomes effect the same feature

Question 5

species

Answer 5

similar organisms that can reproduce and give fertile offspring

Question 6

gene pool

Answer 6

total number of alleles that are present in a population

Question 7

allele frequency

Answer 7

the proportion of a certain allele in a gene pool expressed as a decimal

Question 8

hardy Weinberg conditions

Answer 8

no mutations
no movement of alleles
large population
no selection
mating is random
diploid organisms
P2+q2+2Pq=1
P+q=1

Question 9

suggest how speciation happened to produce two species

Answer 9

1. geographical isolation
2. reproductive separation so no gene flow
3. different selection pressures or different environments
4. variation due to mutations
5. advantageous alleles get passed on which changes allele frequency
6. they become so different that they can no longer breed to produce fertile offspring

Question 10

genetic drift

Answer 10

variations in allele frequencies in small populations due to chance
unlikely in large populations as chance variation in allele frequency usually evens out across whole population

Question 11

allopatric speciation

Answer 11

geographical barriers that separates species

Question 12

sympatric speciation

Answer 12

ecological barriers- different environment in the same area
behavioural barriers- different barriers

Question 13

evolution

Answer 13

formation of new species from pre existing species over time as a result of changes to gene pool and allele frequencies from generation to generation

Question 14

community

Answer 14

populations of different species form a community

Question 15

ecosystem

Answer 15

a community ad the non living components of it environment together form an ecosystem

Question 16

niche

Answer 16

role that a species plays within a habitat

Question 17

carrying capacity

Answer 17

an ecosystem supports a certain size of population of a species called the carrying capacity

Question 18

interspecific vs infraspecific competition

Answer 18

inter- competes for same resources between different species
intra- competes for same resources between same species

Question 19

mark release recapture

Answer 19

1. Capture and count animals
2. Mark them in a way which is not toxic/harmful to them
3. Release them back into the community.=
4. Capture a second sample and count them
5. Record the number of marked individuals recaptured.The estimated population size is:(total no. in 1st sample x total no. in 2nd sample) / no.of marked individuals recaptured

Question 20

mark release recapture assumptions

Answer 20

1. few births and deaths
2. population has a definite boundary
3. first sample distributes evenly amongst population and has enough time to do so

Question 21

primary succession

Answer 21

1. colonisation by pioneer species
2. change in environment allows other species to colonise
3. change in diversity
4. stability increases as less hostile environment
5. climax community reached