Topic 4.5 - Species & Taxonomy Flashcards
What is a species?
A group of organisms that can interbreed to produce fertile offspring
Suggest why 2 different species are unable to produce fertile offspring? (2)
1) Different species have different chromosome numbers -> offspring may have off chromosome number
2) So homologous pairs cannot form -> meiosis cannot occur to produce gametes
Explain why courtship behaviour is a necessary precursor to successful mating (5)
1) Allow recognition of members of same species -> so fertile offspring produced
2) Allows recognition / attraction of opposite sex
3) Stimulates / synchronises mating
4) Indicates sexual maturity
5) Establishes a pair bond to raise young
Describe a phylogenetic classification system (2)
1) Species arranged in groups, called taxa, based on their evolutionary origins and relationships
2) Uses a hierarchy:
- Smaller groups are placed within larger groups
- No overlap between groups
Name the taxa in the hierarchy of classification (8)
King Phillip came over for good soup
1) Domain
2) Kingdom
3) Phylum
4) Class
5) Order
6) Family
7) Genus
8) Species
How is each species universally identified?
A binomial consisting of the name of its genus and species e.g. Homo sapiens
Suggest an advantage of binomial naming
Universal so no confusion as many organisms have more than one common name
How can phylogenetic trees be interpreted? (3)
1) Branch point = common ancestor
2) Branch = evolutionary path
3) If 2 species have a more recent common ancestor, they are more closely related
Describe 2 advances that have helped to clarify evolutionary relationships between organisms
1) Advances in genome sequencing -> allowing comparison of DNA base sequences
2) Advances in immunology -> allowing comparison of protein tertiary structure
How have advances in genome sequencing help clarify evolutionary relationships between organisms (2)
1) More differences in DNA base sequences -> more distantly related / earlier common ancestor
2) As mutations build up over time
How have advances in immunology help clarify evolutionary relationships between organisms (3)
1) Higher amount of protein from one species binds to antibody against the same protein from another species -> more closely related / more recent common ancestor
2) As indicates a similar amino acid sequence and tertiary structure
3) So less time for mutations to build up
