biology

Question 1

what are species

Answer 1

a group of individuals that are more or less alike and are able to interbreed under natural conditions to produce fertile offspring.

Question 2

What is a population

Answer 2

is a group of individuals of the same species living together in a particular place at a particular time.

Question 3

what is a gene pool

Answer 3

all the genotypes of individuals capable of reproducing in a population are pooled together. This is referred to as gene pool- a collection of all their genotypes.

Question 4

what is variation

Answer 4

Variation refers to the genetic differences between individuals.

Question 5

what is genotype

Answer 5

the genetic code of a trait

Question 6

what is a phenotype

Answer 6

the expression of the gene

Question 7

what is homozygous

Answer 7

inheritance of similar alleles

Question 8

what is heterozygous

Answer 8

inheritance of dissimilar alleles

Question 9

what is the use of punnet squares

Answer 9

A punnet square is a tool used to determine the probability of an offspring inheriting a characteristic from its parents.

Question 10

What is co-dominance

Answer 10

when neither allele is dominant over the other, so they are both expressed; e.g. AB blood group.

Question 11

what is incomplete dominace

Answer 11

when neither allele is expressed, so a new trait in between is expressed

Question 12

What is the use of a pedigree

Answer 12

A pedigree is a genetic chart that allows the determination or prediction of the genotype of individuals.
It also permits the diagnosis of the nature of the condition

Question 13

What is adaptation

Answer 13

Adaptation is the change in physical structure, function or behaviour of an organism that allows it to survive in an environment.
Adaptation occurs over many generations due to mutations in the germ line

Question 14

What is isolation

Answer 14

Isolation can provide a barrier to gene flow, preventing breeding between groups of the same species. Amongst humans, barriers may be:

Question 15

How does selection work

Answer 15

Selection: those individuals who possess alleles which express characteristics suitable for survival in a particular environment tend to survive and pass on their favourable alleles to their offspring.
Those who have unfavourable alleles cannot survive in a particular environment and tend to die out and as a result their alleles are eliminated from the gene pool of that population. Therefore, the allele frequency in the gene pool is changed.

Question 16

What is speciation

Answer 16

Speciation is the process of producing a totally different species from an existing species.
It starts when a small fraction of a population is geographically isolated from the main population.
Because of isolation, there is no gene flow between the two isolated populations. Their gene pools are separated.
Over time their gene pools change as a result of natural selection and mutations.
Because the exchange of genetic information (gene flow) is restricted between the two isolated groups, then the two populations will be separated into different breeding groups.
In time, the populations may become so different in behaviour, physical appearance or functioning that interbreeding becomes impossible.