4.3 - Classification And Evolution - New Flashcards
Why do we classify living organisms
- for our convenience
- to make the study of living things more manageable
- to make it easier to identify organisms
- to help us see the relationhsip between species
List the eight different taxonomic levels
Domain Kingdom Phylum Class Order Family Genus Species
What are three domains
- Archaea
- Eubacteria
- Eukaryotae
List the five kingdoms
Animalia Plantae Fungi Protoctista - (all eukaryotes)
Prokaryotae
Species def
A group of organisms that can interbreed to produce fertile offspring
What is the phylogenetic definition of a species?
A group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics
Where, in an ecosystem, do members of the same species live?
The same niche
Kingdom - Prokaryotae info
- no nucleus
- loops of DNA not arranged in linesr chromosomes
- have naked DNA in cytoplasm (not associated with histone proteins)
- have no membrane-bound organelles
- have smaller ribosomes than in other groups (70S, compared to 80S in eukaryotes)
- have cells smaller than that of eukaryotes
- may be free-living or parasitic (some cause diseases)
Kingdom - Protoctista info
- are eukaryotic
- are mostly single-celled (many algae are multicellular, though)
- show a wide variety of forms (all dont belong to other 4 kingdoms
- show various plant or animal-like features
- are mostly free living
- have autotrophic or heterotrophic nutrition, some photosynthesise, some are parasites, etc.
Kingdom - Fungi info
- are eukaryotic
- can exist as single cells - called yeasts
- or have a mycelium that consists of a hyphae
- have cell walls made of chitin
- have cytoplasm that is multinucleate
- are mostly free-living and saprophytic - cause decay of organic matter
Kingdom - Plantae info
- are eukaryotic
- are multicellular
- have cells surrounded by a cellulose cell wall
- are autotrophic (absorb simple molecules and build them into larger organic molecule)
- contain chlorophyll - for photosynthesis
Kingdom - animalia info
- are eukaryotic
- are multicellular
- heterotrophic (digest large molecules to form smaller molecules for absorption)
- are usually able to move around
Heterotroph def
Autotroph def
Saprophytic def
Different biological molecules that can be used as evidence for classification
- cytochrome C
- DNA - base sequences and comparison between species
What is convergent evolution?
Where two unrelated species adapt and ecolve in similar ways, and therefore look very similar
How is cytochrome c used for classification of a species?
- if the sequences are the same, the two species must be closely related
• if the sequences are different, the two species are not so closely related
• the more differences found between the sequences, the less closely related the two species.
How is DNA useful for classification?
- DNA codes for same sequence of amino acids in all organisms - DNA is universal
- can compare DNA base sequences between species
- more similar base sequences show a closer evolutionary relationship - a common ancestor, etc.