4.5 Species and taxonomy

Question 1

What is a species?

Answer 1

A group of organisms that can interbreed to produce fertile offspring

Question 2

Why can’t two different species produce fertile offspring?

Answer 2

• Different species have different chromosome numbers
• So offspring have odd chromosome number
• So homologous pairs cannot form / meiosis can’t occur

Question 3

Why is courtship behaviour important?

Answer 3

• Allows recognition of members of same species
• Allows recognition of opposite sex
• Stimulates release of gametes
• Indicates sexual maturity

Question 4

What is a phylogenetic classification system?

Answer 4

• Species are arranged in groups (taxa) based on their evolutionary origins and relationships
• Uses a hierarchy with smaller groups within larger groups and no overlap between groups

Question 5

How is each species universally identified?

Answer 5

Binomial naming system consisting of its Genus and species

Question 6

What two advances have helped clarify evolutionary relationships?

Answer 6

• Genome sequencing, allowing comparison of DNA base sequences
• Immunology, allowing comparison of protein tertiary structure