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Study of biological diversity in an environmental context, encompassing taxonomy,involving reconstruction of phylogenetic history/ study of organisms and their evolutionary relationships is Systematics .

Taxonomy is branch of Bio that names/classifies forms of life

Phylogeny refers to the evolutionary history of a species/group of related species.

(a) Explain binomial nomenclature of a species and hierarchical classification.- 2 part latinised name- 1 st part genus (genera pl. )- 2 nd part species within the genus

(b) Describe the classification of species into taxonomic groups and appreciatesignificance of various concepts of the species.K ingdom Phylum C lass O ver Family G enus S pecies

(c) Explain relationship between classification and phylogeny- Linnaean scheme is classification based on presumed homologies (anatomicalfeatures of similar function or appearance because they were inherited fromcommon ancestor. The more homologies shared, the closer in evolutionarydistance.) Goal of systematics is to determine phylogeny, by constructing

phylogenetic trees representing hypothesized evolutionary relationships betweenorganisms. To do that, we must have data from classification.

(d) Explain why variation is important in selection- Selection is based on heritable variation. When environmental changes occur,variation allows some individuals to survive better, reproduce more successfully

to produce Fertile Offspring. This ensures perpetuation of species and safeguardsspecies from extinction.

(e) Explain with e.g. how environmental factors act as forces of natural selection.Case study of peppered moth during Industrial Revolution. Melanic moths in

polluted areas can better camouflage with blackened tree trunks where they restedduring the day. Light-colored moths in distant forests were present in higher frequencies.

(f) Explain how natural selection may bring about evolution Natural selection refers to the differential success in reproduction of different phenotypes resulting from interaction of organisms with their environment.

BecauseSpecies produce large number of offspring, but only a constant fraction of theoffspring population will survive, mature and reproduce at reproductive age. Thisis because there is a struggle for survival and reproduction due to competition for limited resources (selection pressures). In a population, variation exists. Naturalselection works upon variation, identifying those better adapted to environment.

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Because of selection pressures, there is the survival of the fittest (relative abilityof individuals to produce fertile, viable offspring) to reproduce ( reachreproductive age to produce fertile, viable offspring), to pass on inheritableselective and reproductive advantages.

ThereforeOvertime, the unequal ability of individuals to survive and reproduce leads togradual change in population= evolution. Certain favorable/advantageouscharacteristics/genotypes accumulate.

(g) Explain why population is smallest unit that can evolve.Population Group of interbreeding individuals belonging to particular species,sharing common geographic area.

Evolution change in allele freq./ mutation, gene flow, genetic drift, randommating, natural selection.

- Evolution is the collective genetic response of a population determiningsurvival or formation of species.

- long term effects of natural selection are at gene level of population becausemembers interbreed and exchange inheritable genes

- Evolution is measured as changes in relative proportions of heritablevariations in successive generations of a population.

(h) Explain how homology (anatomical, embryological and molecular) supportsDarwins theory of natural selection.

Homology is the similarity in characteristics resulting from shared ancestryeven though they may have different functions. E.g. Flipper of dolphin, forelimbof human

Analogy structures with similar functions but based on vastly differentstructures, and organisms do not share common ancestry. E.g. Fish fin and dolphin flipper

Anatomical homology sharing common ancestry in aspect of morphology inform and structureEmbryological homology common ancestry based on similarity of developmental pathways (anatomical characteristics in embryos)

e.g. (comparative embryology) 1. all vertebrate embryos have gill pouches onsides of throat. 30-ady old human embryo has pharyngeal gill pouches likedeveloping fish. 2. vertebrate embryos have a notochord and yet is the only

primitive protochordates that retain this structure in adult. Early in development,human embryos have notochord that becomes greatly reduced, giving rise to discs

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