Species and Taxonomy Flashcards
What is a species?
A group of organisms that can breed and produce fertile offspring.
What is Classification?
Separating organisms into groups based on similarities.
What does classification allow scientists to do?
- Identify a new species.
- Study evolutionary relationships.
- Understand shared traits and adaptations.
What are the major taxonomy ranks used to classify organisms?
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What are the three main domains?
- Bacteria
- Archaea
- Eukarya
What four different kingdoms can the domain Eukarya be divided into?
- Plants
- Animals
- Protoctista ( unicellular organisms)
- Fungi
What is a hierarchy?
Larger groups are separated into smaller ones with no overlap between them. The groups at the top have the largest number of species, and as you go down, the number of species in each group decreases.
Phylogeny
What are courtship behaviours?
Actions that help animals attract mates of the same species and opposite sex.
Why are courtship behaviours important?
- It enables recognition of the same species, leading to successful mating which produces fertile offspring.
- It allows animals of the same species to recognise animals of the opposite sex or members of the population that are mature enough to breed, which leads to successful mating.
What is phylogeny?
The classification of organisms is based on the evolutionary history of those organisms and their ancestors.
How does a phylogenetic tree work?
- The distance between vertical lines shows how far in the past certain organisms branched away from a common ancestor.
- The proximity of organisms to another shows how closely related a species is to another.
- The oldest species are shown on the left, and the newest species are found on the right.
- A point from where two organisms branch off shows when two organisms branched off from a common ancestor.
What was early classification based on and why was this not ideal?
Visible features. This was not reliable as similar features between species do not always mean an evolutionary closeness but that they adapted to the same environment independently.
What is modern classification based on now?
- Comparisons of DNA base sequence or the amino acid sequence of the same protein.
- Comparison of physical characteristics.
- Comparison in courtship behaviours: The more closely related two species are the more similar their courtship behaviours.
How can comparing the DNA base and amino acid sequence of different species help classify how closely related they are?
Over time the DNA base sequence of organisms changes due to random mutations. This means that the more closely related two species are the more similar their DNA base sequence will be. Also since a specific DNA base sequence codes for a specific amino acid sequence. The more closely related the two species are the more similar their amino acid sequences will be. Also, since the amino acid sequence determines where bonds form in a polypeptide chain and the tertiary structure of the protein formed, the more closely related a species is to another,r, the more similar their proteins will be.
