Species and Taxonomy Flashcards
(33 cards)
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.
- Different species have different chromosome numbers → offspring may have odd chromosome number
- So homologous pairs cannot form → meiosis cannot occur to produce gametes
Explain why courtship behaviour is a necessary precursor to successful mating.
- Allows recognition of members of same species → so fertile offspring produced
- Allows recognition of opposite sex
- Stimulates release of gametes
- Indicates fertility
- Establishes a pair bond to raise young
Describe a phylogenetic classification system.
- Species (attempted to be) arranged into groups, called taxa, based on their evolutionary origins (common ancestors) and relationships
- Uses a hierarchy:
- Smaller groups are placed within larger groups
- No overlap between groups
Name the taxa in the hierarchy of classification.
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
How is each species universally identified?
A binomial consisting of the Genus name and then the Species name.
Suggest 2 advantages of binomial naming.
Universal so no confusion and shows how close species are.
State two advances that have helped to clarify evolutionary
relationships between organisms.
Advances in genome sequencing.
Advances in immunology
What is the advance in genome sequencing?
Allowing comparison of DNA base sequences.
What is the advance in immunology?
Allowing comparison of protein
tertiary structure.
Describe the advance in genome sequencing?
- More differences in DNA base sequences → more distantly related.
- As mutations build up over time.
Describe the advance in immunology.
● Higher amount of protein from one species binds to antibody against
the same protein from another species → more closely related / more
recent common ancestor
● As indicates a similar amino acid sequence and tertiary structure
● So less time for mutations to build up.
What is the naming system called?
Binomial system
How do you write the name of a species using the binomial system?
When you name an animal, you write it in italics and the genus gets a capital, the species doesn’t.
How were species originally classified?
Based on visible similarities - fossil records, appearances and behaviour.
Why do different species look similar?
- They live in a similar environment.
- They have similar selection pressures.
- Similar alleles will have the selection advantage.
- Produces similar proteins and thus have similar characteristics.
What is each group in the hierarchy known as?
Taxa
What is a hierarchy?
A hierarchy is smaller groups arranged within larger groups. There is no overlap between the groups.
What is the broadest way to classify organisms?
Domain
What is domain split into?
Archaea
Prokaryotes
Eukaryotes
What are 3 reasons for a classification system?
To understand relationships between organisms and keep track of changes.
It needs to be universal.
The system is based on putting organisms into groups.
4 Ways to classify organisms.
DNA sequence
mRNA sequence
Amino acids sequence
Immunologically
What is phylogenetic classification?
Phylogenetic classification arranges species into groups according to their evolutionary origins and relationships.
What does phylogeny tell us?
Phylogeny tells us who’s related to whom and how closely related they are.
