Hardy Weinberg and Natural Selection Quiz

Gene Pool

All the alleles available in a population’s genotypes

Alleles

Genes responsible for coding characteristics

Hardy Weinberg Equation for Expected Genotypes

p² + 2pq + q² = 1

Hardy Weinberg Equation for Expected Alleles

q + p = 1

q

The H-W symbol for recessive allele

p

The H-W symbol for dominant allele

2pq

The H-W symbol for heterozygous genotype

p²

The H-W symbol for homozygous dominant genotype

q²

The H-W symbol for homozygous recessive genotype

The criteria for Hardy Weinberg

No natural selection

Random Mating

All genotypes viable and equal

NO mutations

NO migrations

Large population size

• Expected at equilibrium

Heritable Traits

traits inherited form parent, from the individuals genotype

Acquired Traits

Traits acquired while growing up, limited by the individual’s genotype, shown in the individual’s phenotype

The Five Major sources of evolutionary change

1. Mutations

2. Genetic Drift

3. Gene Flow

4. Non-random Mating

5. Natural selection

The 2 ways to maintain genetic variability

(all evolution requires variation in heritable traits)

1. Mutations - mutations are rare and can e good or bad for the organism’s fitness

2. Sexual reproduction - recombination of crossing over increases variation, more diverse populations have more variability, relatives mating makes it more possible a mutation will appear (inbreeding)

Mutations

forming new alleles, random and unpredictable

Genetic Drift

Chance events that may increase or decrease allele frequencies. a mechanism of evolution characterized by random fluctuations in the frequency of a particular version of a gene (allele) in a population. Though it primarily affects small, isolated populations, the effects of genetic drift can be strong, sometimes causing traits to become overwhelmingly frequent or to disappear from a population.

Bottleneck

A population bottleneck is an event that drastically reduces the size of a population. The population bottleneck produces a decrease in the gene pool of the population because many alleles, or gene variants, that were present in the original population are lost. Due to the event, the remaining population has a very low level of genetic diversity, which means that the population as a whole has few genetic characteristics.

Gene Flow

Gene flow is the transfer of genetic information from one population to another. Also known as gene transfer or gene migration, it plays a crucial role in the evolution and adaptation of species.

Non-Random Mating

If individuals nonrandomly mate with other individuals in the population, i.e. they choose their mate, choices can drive evolution within a population. Traits that lead to more matings for an individual lead to more offspring and through natural selection, eventually lead to a higher frequency of that trait in the population.

Sexual Dimorphism

the physical and behavioral differences between males and females of the same species—evolved through a combination of unequal reproductive costs, sexual selection, and natural selection.

Environmental Variation

differences in the environment promote specific genotypes

ex: bugs in environments treated with more pesticides will be more pesticide resistant while bugs in environments treated with less pesticides will be less pesticide resistant.

Natural Selection , 3 methods

non-random evolutionary mechanism that can make organisms better suited to their environment.

1. Variation

2. Heritability

3. Different Fitness