Unit 4 - Species + Taxonomy Flashcards
What is classification?
The organisation of living organisms into groups.
What is taxonomy?
The theory + practice of biological classification.
What is a taxon? (Plural taxa)
Each group within a natural biological classification. It contains organisms that share some basic features indicating that they have a more recent common ancestor than they do with other taxa.
Definition of species?
When 2 organisms can breed together to produce fertile offspring.
What is a hierarchy?
A hierarchy is smaller groups within larger groups and there is no overlap between the groups.
What is a phylogenetic classification system?
It attempts to arrange species into groups based on their evolutionary relationships and origins.
Explain what is meant by a phylogenetic hierarchy?
-smaller groups within larger groups
-there is no overlap between groups
-organisms are grouped based on their evolutionary relationships
How do phylogenetic trees work?
The oldest species is at the base of the tree while the most recent ones are represented by three ends of the branches.
How are organisms first sorted into 3 large groups?
1) Eukaryota (plants, animals, fungi, protists)
2) Bacteria (prokaryotes)
3) Archea (prokaryotic organisms which live in extreme environments that rely on other chemical reactions other than respiring oxygen and glucose to live)
What is the taxonomical hierarchy?
1) Domain
2) Kingdom
3) Phylum
4) Class
5) Order
6) Family
7) Genus
8) Species
What is the difficulty in defining species?
-species are not fixed, they change and evolve over time
-within a species there can be considerable variation among individuals
How are species named?
Universally identified by a binomial name. Genus species
The genus part always begins with a capital letter.
The species part NEVER begins with a capital letter.
The binomial name is either written in italics or underlined.
Homo sapiens or H.sapiens
Why is courtship behaviour useful to animals?
-To recognise members of their own species
-To recognise a mate of the opposite sex
-Stimulates release of gametes
-Indication of fertility and sexual maturity
How can courtship behaviour be used for classification?
It is species specific so only members of the same species will do and respond to that courtship behaviour.
How can you classify species by using DNA and proteins?
Genome sequencing:
Entire base sequences of DNA can be determined which can then be compared between organisms. Closely related species will have a higher percentage of of similarity in their DNA base sequences.
Comparing amino acid sequences:
The sequence of amino acids in proteins is coded for by the base sequence in DNA. More closely related organisms will have similar DNA sequences and so similar amino acid sequences in their proteins.
