Genetics, populations, evolution and ecosystems

Question 1

define Genotype

Answer 1

The different alleles an organism has

Question 2

define Phenotype

Answer 2

The characteristics an organism has a result of it’s genotype

Question 3

Define Homozygous

Answer 3

When two copies of the same allele are present at a locus

Question 4

Define codominant

Answer 4

When both alleles are expressed in the phenotype as neither are recessive

Question 5

True or false: there are only two alleles of each gene

Answer 5

False - each person only usually has two alleles but many can exist

Question 6

Give three types of alleles relating to expression of characteristics

Answer 6

Dominant, recessive, codominant

Question 7

What is monohybrid inheritance

Answer 7

Inheritance of a characteristic controlled by a single gene

Question 8

What is phenotypic ratio

Answer 8

The ratio of different phenotypes in the offspring

Question 9

What is epistasis

Answer 9

When an allele of one gene blocks the expression of another

Question 10

Give the equation for the chi-square value

Answer 10

(O-E)2
x2= funny E ————-
E

Question 11

When is the chi-squared test used

Answer 11

To see if the results of an experiment support a theory

Question 12

Define species

Answer 12

A group of similar organisms that can reproduce fertile offspring

Question 13

Define population

Answer 13

A group of organisms of the same species living in a particular area at a particular time. They must have the potential to interbreed

Question 14

define gene pool

Answer 14

The complete range of alleles in a population

Question 15

State the equation for genotype frequency per the Hardy-Weinberg principle

Answer 15

p2 + 2pq + q2 =1

Question 16

Give two conditions required for the hardy-weinberg principle to be valid

Answer 16

A large population with no immigration, emigration, mutations or natural selection. There must be random mating - all possible genotypes catered with others

Question 17

What does the hardy-weinberg principle predict

Answer 17

The frequency of alleles in a population won’t change from one generation to the next

Question 18

What is the primary source of genetic variation

Answer 18

mutation

Question 19

Give three examples of environmental factors which can lead to variation

Answer 19

food
climate
lifestyle

Question 20

What two processes can evolution occur by

Answer 20

genetic drift

natural selection

Question 21

What is the term for pressures that affect an organism’s survival chance

Answer 21

selection pressures

Question 22

How does the frequency of beneficial alleles change from one generation to the next

Answer 22

it increases

Question 23

Give the three types of natural selection

Answer 23

stabilising selection
directional selection
disruptive selection

Question 24

What is speciation

Answer 24

the development of a new species from an existing species

Question 25

How do allopatric and sympatric speciation differ

Answer 25

Allopatric requires populations to be geographically isolated, sympatric is in populations that aren't isolated from one another

Question 26

Give an example of something which could cause allopatric speciation

Answer 26

formation of a river on a landscape

Question 27

How may mechanical changes lead to reproductive isolation

Answer 27

change in shape of reproductive organs means two groups of a species can no longer engage in reproduction

Question 28

In what communities does evolution occur via genetic drfit

Answer 28

small ones

Question 29

What is an ecosystem

Answer 29

All the organisms living in a community plus all the abiotic conditions in the area in which they live

Question 30

Give an example of as many of the following as you can 1) Biotic factors 2) Abiotic factors

Answer 30

1) predator presence, abundance of food | 2) Temperature, water abundance, O2 abundance, CO2 abundance, nutrient availability

Question 31

What is a niche

Answer 31

a niche is the role a species plays in its environment

Question 32

What happens if two species occupy the exact same niche

Answer 32

They compete till one dies out or till one adapts to occupy a different niche

Question 33

Why may the carrying capacity of an ecosystem vary

Answer 33

abiotic and biotic factors may change, making it more/less hostile

Question 34

Describe the difference between interspecific and intraspecific competition

Answer 34

interspecific is when organisms of different species compete for the same resource. Intraspecific is when organisms of the same species do so

Question 35

How can the size of a population be estimated for slow moving/non motile organisms

Answer 35

Using quadrants or transects placed at random intervals

Question 36

How can the size of a population be estimated for motile organisms

Answer 36

Using nets or other methods to capture organisms, marking, releasing and recapturing

Question 37

When performing the mark-release-recapture method of estimating population size what assumptions must be made

Answer 37

The sample has enough time to reintegrate with the population. The marking hasn't affected the individual's survival chance. There are no changes to population size due to births, deaths or migration during the study

Question 38

Give the equation used to estimate population size through mark-release-recapture

Answer 38

number caught in first sample x number caught in second sample divided by number marked in second sample

Question 39

What is meant by the phrase "ecosystems are dynamic systems"

Answer 39

They are constantly changing

Question 40

In primary succession, what is the first species to colonise an area called

Answer 40

pioneer species

Question 41

How do pioneer species change the abiotic conditions

Answer 41

They make them less harsh

Question 42

When a new species moves into the area, what happens to the pioneer species

Answer 42

it is outcompeted

Question 43

What does this eventually lead to

Answer 43

a climax community

Question 44

How does secondary succession differ from primary succession

Answer 44

it starts on land that has had organisms on previously

Question 45

What is a plagioclimax

Answer 45

when succession is stopped artificially by humans

Question 46

Why do humans often manage succession

Answer 46

to conserve species

Question 47

State four ways it is possible to help conserve species

Answer 47

``` managing succession seed banks captive breeding fishing quotas protected areas ```