A3.1 diversity

where does variation come from

where does variation come from

• sexual reproduction (mixing of two organisms’ dna, production of gametes)

• mutations in dna

• errors in dna replication

• viral injection of foreign dna

• environmental and epigenetics effects on gene expression

variation

difference in traits between individuals of the same species

morphological species concept

species as groups of organisms with shared morphological (physical) traits

variation as a defining feature of life

no two individuals are identical in all their traits

naming system of organisms

binomial nomenclature

parts to binomial nomenclature

• genus first with capital letter

• species second, lowercase

biological species concept

a species is a group of organisms that can breed and produce fertile offspring

geographical isolation for speciation

physical habitats such as rivers, oceans, mountains disjunct habitats

behavioural isolation for speciation

two populations are capable of interbreeding but have different behaviours such as courtship rituals

temporal isolation for speciation

two population reproduce/mate at different times