Variation, Classification and Natural Selection Flashcards
what does evolution suggest?
that all organisms are descended from a common ancestor as a result of mutation and natural selection, leading to speciation
what is a phylogenetic group?
a group organisms are placed in according to their evolutionary history
what defines a species?
individuals can interbreed and produce fertile offspring
what falls into a Genus?
several species which have some features in common
what are the taxonomic groupings in descending order of size?
DOMAIN KINGDOM PHYLUM CLASS ORDER FAMILY GENUS SPECIES
What are the features of taxonomic classification?
- a hierarchy (large groups containing smaller groups)
- no overlap between these groups
- organisms share a common evolutionary history
what are homologous features?
the characteristics used to define a given group
what are types of homologous features?
- similar biological structures
- details of embryological development
- shared biochemistry (e.g. metabolic pathways, protein structure/amino acid sequence)
- DNA sequences
What are the 5 kingdoms?
- Animalia
- Plantae
- Fungi
- Protoctista
- Prokaryotae
what does the kingdom animalia include?
- all 5 classes of vertebrates (mammals, birds, reptiles, amphibians, fish)
- invertebrates (insects and other arthropods, molluscs, segmented worms, roundworms, tapeworms/flukes and jellyfish)
what are features of the organisms of kingdom animalia?
- eukaryotic and multicellular
- have no cell walls
- cannot make food (heterotrophic)
- have muscles and nervous systems
what does the kingdom plantae include?
flowering plants, conifers and ferns along with much simpler plants such as mosses and liverworts (not algae/seaweeds)
what are features of the kingdom plantae?
- eukaryotic and multicellular
- cell walls made from cellulose
- usually large vacuole in mature cells
- most have leaves, stems and roots
- most possess chlorophyll and make food by photosynthesis (autotrophic)
- few are modified to parasitic way of life
what is included in the kingdom fungi?
filamentous fungi and yeasts
what are the features of the kingdom fungi?
- single celled fungi called yeasts
- eukaryotic but multicellular fungi do not have separate cells, nuclei dotted around in tissue
- cell walls contain chitin
- feed by extracellular digestion, secreting enzymes onto food and absorbing soluble products
- most feed on dead material (saprotrophic)
- some parasitic causing damage to the host
What does the Kingdom protoctista include?
single cells protozoans such as amoeba, plasmodium, algae (including seaweed) and sponges
what features do kingdom protoctista have?
- seem to have very little in common, assembly of organisms that couldn’t be put into any other kingdom (taxonomic dustbin)
- based on ancestry and evolutionary relationships
- cells are eukaryotic but show a diversity of cell types
- feed in a variety of ways
what is included in the kingdom prokaryotae?
- bacteria
- single celled prokaryotic organisms
what are the features of kingdom prokaryotae?
- cells are much smaller than that of eukaryotes
- most feed by extracellular digestion, secreting enzymes and absorbing the soluble products
- most feed on dead material (saprotrophs), some parasitic
- cyanobacteria are photosynthetic
reproduce mainly by binary fission, but can reproduce sexually
what are the 2 types of variation?
continuous variation
discontinuous variation
what are polygenic traits?
- traits controlled by two or more separate gene pairs
what are some examples of polygenic traits?
- height
- eye colour
- intelligence
- skin colour
- many forms of behaviour
What are the 5 features of polygenic traits?
- not expressed as absolute or discrete characters
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