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Unit 7: Natural Selection

13 dot points across 13 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does artificial selection compare with natural selection?

Topic 7.3 Artificial Selection: explain how humans drive evolution through artificial selection and how it differs from natural selection.
A focused answer to AP Biology Topic 7.3, covering selective breeding, how artificial selection changes allele frequencies, examples in crops and livestock, and the comparison with natural selection, with a worked example.
9 min answer →

What features shared by all living things point to a common ancestor?

Topic 7.7 Common Ancestry: describe the structural and molecular features shared by all organisms that indicate common ancestry.
A focused answer to AP Biology Topic 7.7, covering the shared features of all life (DNA, the genetic code, ribosomes, core metabolism, membranes) that indicate common ancestry, and how conserved features reveal deep relationships, with a worked example.
9 min answer →

How do we know evolution is still happening today?

Topic 7.8 Continuing Evolution: explain how ongoing examples such as antibiotic resistance and pesticide resistance show that evolution continues.
A focused answer to AP Biology Topic 7.8, covering observable, ongoing evolution including antibiotic and pesticide resistance, emerging diseases, and how these illustrate natural selection in real time, with a worked example.
10 min answer →

What kinds of evidence support the theory of evolution?

Topic 7.6 Evidence of Evolution: describe the lines of evidence (fossil, anatomical, molecular, biogeographical) that support evolution.
A focused answer to AP Biology Topic 7.6, covering fossil, anatomical (homologous and vestigial structures), embryological, molecular and biogeographical evidence for evolution, with a worked interpretation of molecular data.
10 min answer →

What causes extinction, and how does it shape the diversity of life?

Topic 7.11 Extinction: explain the causes of extinction, including mass extinctions, and its role in shaping biodiversity.
A focused answer to AP Biology Topic 7.11, covering the causes of extinction, background versus mass extinction, the five mass extinctions, adaptive radiation after extinction, and the current human-driven loss, with a worked example.
9 min answer →

How can we tell whether a population is evolving at a gene?

Topic 7.5 Hardy-Weinberg Equilibrium: use the Hardy-Weinberg equations to calculate allele and genotype frequencies and test whether a population is evolving.
A focused answer to AP Biology Topic 7.5, covering the Hardy-Weinberg conditions, the equations p + q = 1 and p squared plus 2pq plus q squared = 1, and how to calculate and interpret allele and genotype frequencies, with worked calculations.
11 min answer →

What conditions are required for natural selection to occur?

Topic 7.1 Introduction to Natural Selection: explain the conditions required for natural selection and how it leads to changes in a population.
A focused answer to AP Biology Topic 7.1, covering Darwin's reasoning, the conditions for natural selection (variation, heritability, overproduction, differential reproduction), fitness, and how selection changes allele frequencies, with a worked example.
10 min answer →

How do different modes of natural selection shape phenotype distributions?

Topic 7.2 Natural Selection: explain how directional, stabilizing and disruptive selection change the distribution of phenotypes in a population.
A focused answer to AP Biology Topic 7.2, covering directional, stabilizing and disruptive selection, sexual selection, and how each changes a phenotype distribution, with a worked interpretation of selection on a trait.
10 min answer →

What scientific models explain how life could have originated on Earth?

Topic 7.13 Origin of Life on Earth: describe the scientific models for the origin of life, including the RNA world and the evidence supporting them.
A focused answer to AP Biology Topic 7.13, covering models for the origin of life, the formation of organic monomers, the RNA world hypothesis, protocells, the geological timeline, and the evidence behind these models, with a worked example.
10 min answer →

How do phylogenetic trees represent evolutionary relationships?

Topic 7.9 Phylogeny: interpret and construct phylogenetic trees and cladograms from shared characters and molecular data.
A focused answer to AP Biology Topic 7.9, covering phylogenetic trees and cladograms, shared derived characters, nodes and common ancestors, out-groups, and reading relatedness from a tree, with a worked tree interpretation.
10 min answer →

What processes change allele frequencies in a population?

Topic 7.4 Population Genetics: explain how natural selection, mutation, gene flow, genetic drift and non-random mating change allele frequencies.
A focused answer to AP Biology Topic 7.4, covering the gene pool, allele frequencies, and the five mechanisms of microevolution (selection, mutation, gene flow, genetic drift, non-random mating), including bottleneck and founder effects, with a worked allele-frequency calculation.
11 min answer →

How do new species form from existing ones?

Topic 7.10 Speciation: explain how reproductive isolation leads to speciation, including allopatric and sympatric speciation.
A focused answer to AP Biology Topic 7.10, covering the biological species concept, reproductive isolation (prezygotic and postzygotic barriers), allopatric and sympatric speciation, and rates of speciation, with a worked example.
10 min answer →

Why is genetic variation within a population important for its survival?

Topic 7.12 Variations in Populations: explain why genetic variation within a population is important for survival and the response to environmental change.
A focused answer to AP Biology Topic 7.12, covering the sources and importance of genetic diversity, how variation buffers populations against change, the risks of low diversity, and the role of variation in evolution, with a worked example.
9 min answer →