Genetic variation and change (AS91157) | Baamboozle - Baamboozle

Define evolution

Is the change in the characteristics of a species over time and relies on natural selection.

What is migration?

Movement of organisms into (immigration) and out (emigration) of a population.

Define: natural selection

The process by which heritable traits increase an organism's chances of survival and reproduction.

What is a pedigree chart?

A diagram that depicts the biological relationships between an organism and its ancestors

What is a test cross?

A genetic cross between a homozygous recessive individual and a corresponding suspected heterozygote to determine the genotype of the latter.

What does multiple alleles mean?

When three or more alternative forms of a gene (alleles) can occupy the same locus. e.g. ABO blood types

Define Haploid

When a cell has half the usual number of chromosomes.

What is the genotype ratio of the punnett square?

3RRTT, 4RRTt, 1RRtt, 3RrTT, 4RrTt, 1Rrtt,

Define: complete dominance

The dominant allele in a heterozygous individual completely masks the effect of the allele that is recessive

Define: diploid

A cell or an organism consisting of two sets of chromosomes: usually, one set from the mother and another set from the father.

Define: Incomplete dominance

Heterozygous individuals have a phenotype that is intermediate between the two homozygous phenotypes

What is a Chiasma?

The point of contact, the physical link, between two (non-sister) chromatids belonging to homologous chromosomes during crossing over

Linked genes are...

Genes located on the same chromosome that tend to be inherited together

Fertilisation

The union of male (sperm) and female (ovum) gametes to produce a diploid zygote in reproduction

The type of cell division which produces gametes

Meiosis

Define: Population bottleneck

An event that drastically reduces the size of a population. It may be caused by various events, such as an environmental disaster.

What is a somatic cell?

Body cells. If a mutation occurs in these cells, it will not be passed on to offspring.

Define: phenotype

The physical appearance of the organism

What is a gene?

A length of DNA that holds the instructions for a characteristic

What is the genotype?

The genetic make-up of the organism

Define: Mutation

A permanent change in the bases on DNA. It is the only way of creating new alleles

Define: heterozygous

Different forms of the allele are present in the genotype e.g. Hh

What is: Alleles that produce a gene product that kills the offspring

Lethal genes

Define: Genetic drift

The change in frequency of an existing gene variant (allele) in a population due to random chance alone and not natural selection.

What is sexual reproduction?

Reproduction involving two parents. Produces genetic variation.

What is Asexual reproduction?

Reproduction involving only one parent. Doesn’t produce genetic variation.

Define: Gene pool

Refers to the total number of alleles of every individual in a population.

What is crossing over?

During meiosis, when the homologous chromosomes line up at the equator, they can exchange genetic information.

What is F1

The parental generation (P) is the first set of parents crossed. This generation consists of all the offspring from the parents.

Define: pure breeding

A group of identical individuals that only produce one type of gamete due to the fact they are homozygous

What are homologous chromosomes?

Chromosome pairs (one from each parent) that are similar in length, gene position, and centromere location.

Define: co-dominance

Heterozygous individuals have a phenotype that shows the phenotype of both parents

Define: selection pressure

Environmental factors that influence the survival and reproductive success of individuals within a population.

What is independent assortment?

The way the homologous chromosomes line up at the equator maternal and paternal, is completely random

Define: homozygous

The same form of the allele is present in the genotype e.g. HH, hh

Define: allele frequency

A measure of the relative frequency of an allele on a genetic locus in a population.

Describe: founder effect

The loss of genetic variation when a new population is established by a very small number of individuals from a larger population.

What is genetic diversity?

A measure of the different genetic combinations within a gene pool

Describe: segregation

The process that occurs during meiosis where pairs of alleles are separated when the homologous chromosomes split

Define: gamete

Sex cell of an organism e.g. sperm, egg, pollen or ova

Define: Allele

Different forms of a gene due to slightly different order of bases e.g. brown eyes and blue eyes