Classification and Biodiversity Flashcards
What is phylogenetics?
The study of evolutionary history and relationships among organisms. Can be represented as a tree. Closely related organisms share a more recent common ancestor
What is classification?
The placing of organisms into groups. Larger groups are divided up into progressively smaller groups, forming a hierarchy
What is meant by hierarchy?
A system of ranking in which small groups are nested components of larger groups
The identification and naming of organisms is called ——— Each group within a classification system is called a ————
Taxonomy, taxon
What is the acrostic to remember the hierarchy of biological classification?
Do
Kinky
Pants
Come
Off
For
Good
Sex
State the order of the hierarchy of biological classification
Domain
Kingdon
Phylum
Class
Order
Family
Genus
Species
What does a classification system help us to do?
Infer evolutionary relationships, indicating that organsims in the same taxon are closely related
It improves scientific communication by providing concise terms like ‘bird’
Why may scientific names for organisms change?
Classification systems are tentative and may change as scientific knowledge advances
What are the three domains?
- Bacteria (eubacteria): the true bacteria such as E.coli and Salmonella
- Archaea (archaebacteria): extremophile bacteria living in diverse conditions such as high temperature, pH, salinity and pressure
- Eukaryota: all eukaryotic organisms, including plants, animals, fungi and protoctists
What are the five kingdoms?
- Prokaryota
- Protoctista
- Fungi
- Animalia
- Plantae
Describe prokaryota
Microscopic organisms
All bacteria and Cyanobacteria
Features include 70S ribosomes, peptidoglycan cell walls, circular DNA not enclosed within a nucleus, lacks membrane bound organelles
Describe protoctista
Mainly single celled. Lack tissue differentiation. Examples include plankton, spirogyra, amoeba
Describe fungi
Cell walls made of chitin and can reproduce both asexually and sexually
Sexual reproduction produces spores, helping fungi to adapt to changing environments
Examples include single celled yeast and moulds
Describe animalia
Multicellular organisms with nervous coordination and no cell walls.
Describe plantae
Multicellular organisms that photosynthesise and have cell walls made of cellulose
What is a phylum?
A subgroup of a kingdom, defined by body plan
What is a class?
A subgroup of phylum combining taxa with a distinct level of complexity
What is a species?
A group of phenotypically similar organisms that can interbreed to produce fertile offspring
Taxonomy involves identifying and naming organisms. What does this allow us to do?
- Discover and describe biological diversity
- Investigate evolutionary relationships
- Classify organisms based on these relationships
What are the 3 advantages of the binomial naming system?
- Unambiguous naming
- Latin based - usable worldwide
- Indicates relatedness when species share part of their name
What are the 2 ways to determine the relationships between organisms?
- Physical features
- Genetic evidence
What are homologous structures?
Structures with different functions but a similar form and developmental origin, indicating a more recent common ancestor
What is divergent evolution?
When evolution from a common ancestral structure gives rise to structures that perform many different functions
What is an example of divergent evolution?
Pentadactyl limb, a five digit limb found in four classes or vertebrates. It evolved to have a different function such as running, swimming, flying, jumping
