Evolution Flashcards
Summarise the evidence that biological evolution occurs:
Fossils Biogeography Comparative anatomy Comparative embryology Molecular biology Plant and animal breeding by humans
What is involved in allopatric speciation?
Allopatric speciation occurs when a population of a species is split by a geographical barrier. Over time, the separate parts evolve according to local pressures so that if individuals are brought together again they can no longer interbreed.
What is involved in parapatric speciation?
Parapatric speciation is similar to allopatric, but the isolation is only partial. Nevertheless, the limited exchange between the populations is not enough to prevent divergence.
What is involved in sympatric speciation?
Sympatric speciation occurs without any geographic isolation. It arises from errors in meiosis (the cell division that forms gametes). Sympatric speciation is far more common in plants, because many can self-fertilise.
Why is it useful to name organisms?
Allows everyone to know exactly which organisms are being referred to. Allows legal protection of species.
Explain the advantages of a classification based on evolutionary relationships among organisms:
It indicates how recently groups had a common ancestor, and thus how genetically divergent they are. In general, the higher the taxonomic rank, the more powerful the arguments in favour of conservation. Allows prediction of traits expected in related organisms.
Explain the differences between homologous and analogous characters:
Homologous characters are present because of the common phylogenic history of the organisms.
Analogous characters have developed to fulfil similar functions in different organisms, but they have arisen through completely different phylogenies.
What is the difference between a classification and a key?
Hey classification is a grouping of organisms according to some system (flower colour, growth form, phylogeny etc)
A key is a set of clues/instructions on own to identify an organism.
Name the three domains and six kingdoms of life:
Domains: Archaea, Bacteria and Eukarya.
Kingdoms: Bacteria, Archaea, Protista, Plantae, Fungi and Animalia
Summarise the key differences between prokaryotes and eukaryotes:
Key differences are that prokaryotes have no membrane-bound organelles whiling eukaryotes there are mitochondria and plastids and a nucleus. Prokaryote DNA is a single circular strand, while in eukaryotes is it arranged in one or more linear chromosomes. (Other less important differences include cell size, the size of ribosomes, composition of the cell wall and mode of cell division.)
Summarise the key differences between Archaea and Bacteria:
Key differences are the presence of introns in some Archaea genes but not in Bacteria, protein synthesis is not inhibited by the antibiotics chloramphenicol, streptomycin and kanamycin which do not inhibit protein synthesis in Bacteria. (Other less important differences are differences in the cell wall, plasma membrane and flagella structure and function.)
Define with examples the four major nutritional strategies of organisms:
Photoautotrophy - capture light energy to drive the biosynthesis of their organic compounds, using only CO2 and inorganic elements. Eg: Cyanobacteria, algae and green plants
Chemoautotrophy - CO2 provides their sole carbon source, but their energy comes from the oxidation of inorganic compounds such as hydrogen sulphide or ammonia. Some bacteria are examples. UNIQUE TO PROKARYOTES.
Photoheterotrophy - Sunlight provides their energy source, but they obtain their carbon from organic compounds. Eg: some marine prokaryotes. UNIQUE TO PROKARYOTES
Explain the factors that can limit the population growth of prokaryotes:
Nutrient depletion, pH change, exhaustion of oxygen or the accumulation of toxic wastes.
In the absence of sexual reproduction had a prokaryotes increase genetic diversity in their populations?
Mutation, transformation, transduction.
What is a virus and how does it cause disease?
Of viruse is a subcellular infectious particle composed of DNA or RNA surrounded by a protein coat. Disease is caused as infected cells have damaged membranes, disrupted growth and metabolism.
