3.4.5 species and taxonomy

Question 1

Species

Answer 1

If two organisms belong to the species, they are able to produce fertile offspring

Offspring from 2 different species mating may be infertile because they will have an odd number of chromosomes so can’t perform meiosis to produce sex cells

Question 2

Role of courtship in species recognition

Answer 2

Allows recognition of members of the same species because courtship behaviour is species specific
- production of fertile offspring

Indication of sexual maturity

Recognition/attraction of opposite sex

Stimulate release of gametes

Establishes a pair bond to raise young

Synchronise mating > maximum probability that sperm will fertilise ovum

Question 3

Phylogenetic classification system

Answer 3

Arranges species into groups based on their evolutionary origins and relationships

Each group = taxon

Question 4

Taxa hierarchy

Answer 4

Domain
Kingdom 
Phylum 
Class
Order
Family
Genus
Species

Question 5

Genus + adv

Answer 5

E.g. homo + species e.g. sapien
= homo sapien

Adv = universal; no confusion as many organisms have more than one common name

Question 6

Genome sequencing

Answer 6

Compare the order of base sequence of whole genome of different species

Higher % match = more closely related

Question 7

Immunology

Answer 7

DNA > mRNA > sequence of amino acids in polypeptide chain

So tertiary structure of protein tells us about sequence of DNA
- if same antibody binds to a specific antigen then it is closely related