VCE Biology Unit 4 evolution case studies quiz

Mutation, a changing environment, and the eventual splitting of one species into two

Inherited genes, the gametes that carry them, and the slow gradualism of change over time

Variation, heritability, and differential reproductive success

An available niche, competition between rivals, and predation by other organisms

Genetic drift in small populations, where the dark morph rose by random chance rather than by any selection

Lamarckian inheritance, in which moths darkened during their own lifetime and passed the soot stain to offspring

Polyploid speciation, where a doubling of chromosome number produced a new dark-coloured moth species overnight

Industrial melanism as natural selection driven by predation pressure changing with environmental soot

Selection pressure favouring pre-existing resistant variants, with horizontal gene transfer spreading resistance

Convergent evolution, where unrelated bacterial species independently arrive at the same resistant phenotype

Allopatric speciation, where a physical barrier splits the bacterial population into two reproductively isolated species

Lamarck's giraffe model, in which each bacterium develops resistance through use and then passes it on directly

Gene flow steadily homogenising allele frequencies across all the islands until the finch populations became identical

Adaptive radiation from a common ancestor following geographic isolation and ecological opportunity

Convergent evolution from completely unrelated lineages that happened to arrive on the islands and grew alike

A mass extinction event that wiped out most island finches and left only a few surviving beak shapes behind

Always produces beneficial change, steadily increasing the frequency of the fittest alleles in the population

Cannot occur in animal populations and is restricted to plants, bacteria and other simpler organisms only

Is a random change in allele frequency due to sampling, particularly significant in small populations

Requires consistently high mutation rates to operate, since it depends on a steady supply of new alleles

Two populations simply look different from one another in colour, size or some other visible feature

Two populations live in different habitats, even though they could still interbreed freely if they ever met

One population is hunted to extinction, leaving the other as the sole surviving form of the original species

Two populations can no longer interbreed to produce fertile offspring under natural conditions

Hominin fossils (Lucy, Turkana Boy, Neanderthal), comparative anatomy, mtDNA and Y-chromosome lineages, and molecular clocks

A single complete fossil skeleton that, on its own, is taken to prove the entire pathway from Australopithecus all the way to modern humans

Only DNA evidence, since fossils and comparative anatomy are considered too unreliable to use in human evolution

Only the fossil record, because genetic and molecular data cannot say anything useful about extinct hominin species

Pure multiregional evolution, with modern human populations arising in parallel everywhere and no single African origin at all

Modern humans evolved in Africa and dispersed, with limited interbreeding with Neanderthals and Denisovans in Eurasia

Independent origin on every continent, with each region's people descending from a separate local ancestral hominin

Strict replacement, in which dispersing humans wiped out all archaic hominins and never interbred with any of them

All mammals descending from one common ancestor and then diverging into many different forms over time

Dogs and wolves being closely related and sharing a recent common ancestor with very similar body plans

Marsupial mammals and placental mammals evolving similar body plans for similar niches independently

Genetic drift causing two related populations to slowly come to resemble one another purely by chance

Natural selection is a very important force of evolution that has shaped all of life on Earth over an extremely long period of time, and in this essay I am going to talk about some of the many interesting examples of it that we have studied this year.

In this essay I will write about several different natural selection examples, describing each one in turn and explaining what happened, before finishing with a short summary of everything that I have written about across the whole of the response.

Charles Darwin discovered evolution a very long time ago after his famous voyage, and ever since then scientists all around the world have agreed that his big idea about natural selection is one of the most important discoveries in all of biology.

Antibiotic resistance demonstrates natural selection on a human timescale, with selection pressure from clinical antibiotic use favouring pre-existing resistant variants whose frequencies have risen across global pathogen populations within decades.