Speciation

Convergent

Convergent

________- Occurs when species become similar.

Reproductive Isolating Mechanism

________ (RIM)- any factor that stops members of populations of the same spceices or members of different species from breeding together; it acts as a barrier to gene flow.

Allopolyploidy

________ is the more important of the two as it results in the hybrids containing the genes of two different species which can be advantageous to the polyploid should the selection pressures change.

Deme

________- A local population that has no or limited gene flow with members of other populations.

Divergent

________- Occurs when species become different.

Prezygotic

________- act before the egg is fertilised.

Bottleneck

________ effect may randomly alter allele frequencies and /or remove alleles so that when the population recovers, allele frequencies may not be representative of the original population and genetic diversity is likely to be reduced.

Biological Evolution

________- the genetic change in a population from one generation to another.

single phenotype

A(n) ________ is selected for and the allele frequency shifts in one direction.

Diploid

________- The number of chromosomes in the zygote.

Haploid

________- The number of chromosomes in the gamete.

Genetic drift

________ occurs in small populations and with alleles not greatly affected by selection.

Genome

________- The entire component of genetic material in an organism.

Monoploid

________- The number of chromosomes in each set (Haploid and ________ are interchangeable)

Aneuploidy

________- Only certain chromosomes are represented an unusual number of times.

Gene Pool

________- The number of alleles that occurs in a population.

Emigration

________- Individuals move out of a population.

Vicariance

________- Large- scale allopatric speciation of a taxonomic group by a significant geophysical event.

Immigration

________- Individuals move into a population.

Gene Flow

________- The movement of alleles carried by individuals between populations.

Gametic Isolation

When sperm can not survive in the chemical environment of the female reproductive system.

Euploidy

________- Variation in chromosome number involves the entire genome.

inbreeding

Increases the proportion of homozygotes in the population similar to self- fertilisations.

Autotetraploid

________ has 4 sets.

Speciation

________- The formation of a new species, the result of reproductive isolation.

Autotriploid

________ has 3 sets of chromosomes.

zygote

The ________, embyo or offspring is inevitable so it dies early in its development.

gene flow

Increases the genetic differences between populations by introducing new alleles.

Reproductive isolation

________ may result from just one or a combination of prezygotic and /or postzygotic isolating mechanisms.

desirable phenotypes

Inbreeding increases the chances of favourable alleles coming together and resulting in ________.

Hybrid Breakdown

Occurs when the hybrid reaches maturity and is able to breed but the next generations are infertile or have reduced reproductive capability.

Outbreeding

Offspring produced by outbreeding show hybrid vigour when they contain a variety of alleles from their genetically different parents.

Postzygotic

________- act after the egg is fertlilised.

second division of meiosis

Results from the failure of chromosomes to separate during the first or ________ or in mitosis (results in a tetraploid) because the spindle does not function properly.

Cline

________- A gradient of variation.

Parallel Evolution

________- when two or more related species evolve along similar lines independently.

Populations

________ are the units of evolution and changes in allele frequency in the gene pool of a(n) ________ indicates that evolution is occurring.

Geographical isolation

________ results from physical barriers (rivers, mountains, oceans) separating populations.

Sperm

________ can not penetrate the surface of the egg.

genetic differences

Decrease ________ between populations- If migration is regular and involves large numbers of individuals, accumulated ________ between populations can be reduced by gene flow.

Biological Evolution

the genetic change in a population from one generation to another

Speciation

The formation of a new species, the result of reproductive isolation

Gene Pool

The number of alleles that occurs in a population

Deme

A local population that has no or limited gene flow with members of other populations

Cline

A gradient of variation

Clinal Variation

Must be linked in some way to an environmental gradient

Ring Species

A special case of cline in which the two ends of the cline join to form a loop or ring

Gene Flow

The movement of alleles carried by individuals between populations

Immigration

Individuals move into a population

Emigration

Individuals move out of a population

Genetic Drift

A change in allele frequency due to the accumulated effects of chance

Founder Effect

When a small number of individual animals or plants are dispersed to a distant place, the new arrivals carry only a small portion of the gene pool of the ‘parent population

Genome

The entire component of genetic material in an organism

Haploid

The number of chromosomes in the gamete

Diploid

The number of chromosomes in the zygote

Monoploid

The number of chromosomes in each set (Haploid and Monoploid are interchangeable)

Aneuploidy

Only certain chromosomes are represented an unusual number of times

Euploidy

Variation in chromosome number involves the entire genome

Divergent

Occurs when species become different

Convergent

Occurs when species become similar

Parallel Evolution

when two or more related species evolve along similar lines independently

Co-Evolution

occurs when two species form a mutalistic relationship

Vicariance

Large-scale allopatric speciation of a taxonomic group by a significant geophysical event

Sympatric Species

are (closely) related species that live in the same geographic location

Allopatric Species

are (closely) related species that live in different geographic location

Reproductive Isolating Mechanism (RIM)

any factor that stops members of populations of the same spceices or members of different species from breeding together; it acts as a barrier to gene flow

Prezygotic

act before the egg is fertilised

Postzygotic

act after the egg is fertlilised