Classification And Evolution Flashcards
(39 cards)
Define classification.
The process of naming and organising organism into groups based on their characteristics.
Name the eight groups in the classification hierarchy.
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
What are the components to a binomial name?
Genus and species. In Latin.
What is the advantage of the binomial naming system?
Universal; an organism’s binomial name is the same everywhere in the world.
What are the three domains? What are there key characteristics?
Archaea - 70S ribosomes, 10 proteins in its RNA polymerase, no cell wall.
Bacteria - 70S ribosomes, 5 proteins in its RNA polymerase, peptidoglycan cell wall.
Eukarya - 80S ribosomes, contains 12 proteins, cellulose, chitin or no cell wall.
What are the six kingdoms?
Eubacteria, archae-bacteria, protoctista, fungi, plantae, animalia.
How are organisms classified into a kingdom?
Based on similarities in observable characteristics.
How was the domain system of classification developed?
By analysing molecular differences between organisms to determine their evolutionary relationships (phylogeny).
What is the difference between classifiction and phylogeny?
Classification is simply sorting organisms into groups. Phylogeny investigates the evolutionary relationships between organisms.
Explain how natural selection results in evolution.
- Random mutations result in new alleles.
- Some alleles provide an advantage against selection pressures, making an individual more likely survive and reproduce.
- Their offspring receive the new allele, and are said to have evolved a new characteristic.
- So much change can occur that a new species can be said to have evolved.
How did Darwin and Wallace contribute to the theory of evolution?
Observed that birds have many different beak shapes. Concluded that birds with beak shapes most suited to the food they are more likely to survive and therefore pass this beak shape onto their offspring.
Give other evidence for the theory of evolution.
Fossils - allows us to compare extinct organisms to today’s organisms. More complex organisms nearer the surface.
Comparative anatomy - divergent (animals of different species evolve similar characteristics) and convergent (animals diversify from a common ancestor, evolving a different set of specific and adapted features) evolution. Homologous structures appear different on the surface but have the same internal structure.
Comparative biochemistry - Similarities and differences in the proteins and other molecules that control life processes. Can analyse neutral changes in molecules such as cytochrome C, similar ones show close relation. Ribosomal RNA has a very slow rate of substitution. DNA can be sequenced and the results compared. More similar DNA will have diverged from a common ancestor more recently.
What causes variation?
Genetic - mutations, random fertilisation etc.
Environmental - climate, diet, culture, etc.
Differentiate between intraspecific and interspecific.
Intraspecific - variation within the same species.
Interspecific - variation between different species.
How does phylogenetic classification arrange species?
- into groups according to their evolutionary relationships and origins.
Why is Linnaean classification an example of a hierarchy?
- smaller groups arranged within larger groups.
- no overlap between groups
What advances improved the accuracy of classification?
- genetic sequencing etc
How can comparative biochemistry be used in classification?
- The DNA base sequence of a gene common to many organisms can be compared as a measure of how closely related organisms are.
- Similarity = closer relationship
- Fewer mutations would have accumulated over time
- Same can be done with sequence of amino acids (less accurate due to degeneracy of genetic code)
What is comparative anatomy?
- the comparison of structures between organisms
What are homologous structures and why are they evolutionary evidence?
- They are structures which may appear superficially different and perform a different function from one another, but nevertheless share the same underlying structure.
- example: pentadactyl limb.
- may have evolved from a common ancestor with that bone structure, and has since adapted to fill a new niche. (divergent evolution)
What process leaves to evolution?
- natural selection
Which common protein is often used as evidence for evolution?
- it is found in many different species in mitochondria
- Cytochrome C
What are the three types of adaptation?
- anatomical (features/structures), physiological (processes) or behavioural (actions; genetic or learnt)
What is convergent evolution?
- species exposed to similar selection pressures so similar alleles are naturally selected for.
- Become more genetically similar
