Evolutionary Processes and Speciation

Flashcards covering key concepts in evolutionary processes leading to speciation.

Adaptive Radiation

lots of new species arise in a short time due to vacant niches

Allopatric Speciation

Populations become geographically isolated, stops gene flow leading to speciation

Allopolyploidy

polyploidy, different species mating = hybrid

Autopolyploidy

polyploidy, chromosome sets from same species

Cline

gradual variation in the characteristics of a species over geographical range

Coevolution

When two or more species influence each other's gene pools, acting as selection pressures

Convergent Evolution

develop similar structures in unrelated species due to similar environmental selection pressures

Divergent Evolution

changes in gene pools of two or more populations, leading to new species from a common ancestor

Evolution

cumulative changes occur in heritable characteristics

Founder effect

When individuals from a larger population establish a new population

Gene Pool

total number of genes of every individual in a population

Gene Flow

movement of genes from one population of a species to another

Genetic Drift

change in allele frequency in a population due to random chance

Hybrid

offspring of parents differing in at least one characteristic, usually from different species

Instant Speciation

speciation through polyploidy

Macro-evolution

formation of completely new species

Micro-evolution

accumulation of new characteristics in a species through mutation

Mutation

Permanent change in DNA base sequence, new alleles

Natural Selection

differing success in members of a population

Nondisjunction

Failure of homologous chromosomes to separate during cell division

polyploidy

cell or organism with two or more sets of chromosomes

Population Bottleneck

event drastically reduces population size, decrease gene pool

postzygotic isolating mechanism

isolation preventing fertile offspring formation, including hybrid inviability, sterility, and breakdown.

prezygotic isolating mechanism

isolation preventing fertilisation of eggs, habitat, temporal, behavioural, mechanical, gametic mechanisms

Reproductive Isolation

inability of species to interbreed and produce fertile offspring due to reproductive barriers

Selection Pressure

environmental aspect influencing an individual's success

Speciation

Formation of new species from a common ancestor

Species

group of individuals that can interbreed, produce fertile offspring

Sympatric Speciation

speciation, organisms in same area cannot interbreed, without geographic barrier

Sympatry

groups of organisms that live in the same geographical area