Variation and allele frequency
What is the original source of all new genetic variation in a population?
Mutations
What is the mechanism that drives evolution, where individuals with advantageous traits survive and reproduce?
Natural selection
What type of speciation happens when populations are separated by a geographic barrier?
Allopatric speciation
What are structures called that share an underlying design from a common ancestor, like the forelimbs of humans, whales, and bats?
Homologous structures
Name one feature that all primates share.
Opposable thumbs, forward-facing eyes, sensitive fingertips, or a large cranium
Apart from happening spontaneously, what two things can cause DNA mutations?
Chemicals and radiation (mutagens)
What is the term for an environmental factor (such as a predator) that affects which individuals survive?
Selection pressure
What type of speciation happens without geographic isolation, like the Howea palms flowering at different times?
Sympatric speciation
What type of evolution do homologous structures show?
Divergent evolution
What feature defines hominins?
Upright stance with dedicated bipedalism
What term describes how common an allele is in a population?
Allele frequency
What type of genetic drift happens when an event wipes out most of a population?
Bottleneck effect
What is the name for humans controlling which organisms reproduce, such as farmers breeding high-yield corn?
Artificial selection (selective breeding)
Bat, bird, and butterfly wings evolved separately. What type of evolution does this show?
Convergent evolution (analogous structures)
Where the spine joins the skull, which opening moved forward during human evolution to support bipedalism?
Foramen magnum
A population has 8 alleles for a gene: 2 are A and 6 are B. What is the frequency of allele A?
0.25
What type of genetic drift happens when a small group of individuals colonises a new area?
Founder effect
In antibiotic resistance, what role do antibiotics play in natural selection?
Selection pressure, so resistant bacteria survive to reproduce
What are reduced structures that have lost their function, like the pelvis and femur in whales, called?
Vestigial structures
How did the pelvis change to support bipedalism?
It became shallower and more bowl-shaped, shifting the centre of gravity
Why does a population with high genetic diversity have a better chance of surviving environmental change?
It's more likely that some individuals already carry alleles that are advantageous in the new environment
Which mechanism of evolution increases genetic variation by introducing new alleles through migration?
Gene flow
What is the large, sudden change in viral antigens caused by recombination when a host is infected with two different viruses?
Antigenic shift
Why is comparing DNA sequences more accurate than comparing amino acid sequences?
DNA shows silent mutations, which don't change the amino acid sequence
Mitochondrial DNA shows non-African populations have less genetic diversity than African populations. Which genetic drift event explains this, and why?
The founder effect. Small groups migrated out of Africa, so they carried only a random subset of the original population's alleles.