Continuity of Species ppt 1

What is a gene pool?

A gene pool is the number and type of genes in a population or species or mating pair from which new individuals are generated. New individuals are drawn from the existing pool of genes.

What is Allele frequency?

Allele frequency is the number or proportion of specific genes in a gene pool.

What is population?

Population is the number of individuals of a particular species in an area at a specific time.

What is genetic drift?

Genetic drift is the random changes in a populations gene pool and allele frequencies from generation to generation.

Why does genetic drift have a larger impact on small populations?

Genetic drift has a larger effect on smaller populations as the effect of a few individuals not passing on their genes to the next generation has a larger effect on the gene pool.

What is the difference between the founder effect and the bottleneck effect?

Founder effect is the separation of an existing population into several population with one geographically separated. Bottleneck effect is the natural destruction of part of species/population.

What is reproductive isolation?

Reproductive isolation are reproductive characteristics which prevent species from mating.

What are examples of factors causing reproductive isolation?

Geographical: physical land forms that prevent meeting such as oceans and mountain ranges

Behavioural: occurs when two species have different courtship behaviours

Temporal: occurs when two species mate at different times of year

What’s the relationship between offspring diversity and gene pool?

The more diverse the offspring, the greater the variety of genes in the gene pool.

What’s the relationship between genetic diversity in the gene pool and survival of the population/species?

Increased genetic diversity in the gene pool and therefore diverse offspring, means increased chance of some individuals in a population having the set of genes that assist in surviving.

What’s the relationship between genetic diversity and the size of a population?

Generally larger populations have a greater variety of genes in their gene pools.

What is natural selection?

Natural selection is an organism’s natural environment that determines if its phenotype is advantageous or not. Natural selection selects phenotype not genotype, and is not a random process it is directional.

What is a selective agent?

The selective agent is environmental factor acting on the population.

What is a selection pressure?

The selection pressure is the effect of natural selection acting on the population.

Example of selecting agents

Example include fungus, virus, bacteria, predator, temperature, water availability

Examples of selection pressures

Examples include reduced photosynthesis, increased metabolism, enzymes denatured, death, reduced reproduction

How do genes pools change?

Variation: genetic variation leading to phenotype variations. e.g. disease resistance caused by mutations or genetic drift.

Selection: selecting agents, or selection pressures, also known as natural selection.

Overproduction: not all individuals live to reproduce and pass their genes on. e.g. overproduction of offspring and environmental factors like competition.

Adaptation: the fitter organisms are more likely to survive and reproduce, leaving more adapted offspring to survive that selection pressure.

What is artificial selection?

Selective breeding