All courses · core course
Ecology and Evolution
A core course for biology majors and premedical students. It starts with how evolutionary explanations are tested and how to read a tree, follows selection, drift, speciation and the history of life, then moves up the ecological scales: populations, species interactions, communities, ecosystems, and global change and conservation.
6 units · 26 lessons
Unit 1 · Evidence and evolutionary reasoning
- Unit 1: Evidence and evolutionary reasoning How to Test an Evolutionary Explanation A drought killed most of an island's finches. How would you show that the survivors' children were different?
- Unit 1: Evidence and evolutionary reasoning Reading Phylogenetic Trees A trout is more closely related to you than to a shark. How can a tree show that?
- Unit 1: Evidence and evolutionary reasoning Natural Selection in Ecological Context Birds took dark peppered moths more often than pale ones near Cambridge. By how much, and per what?
- Unit 1: Evidence and evolutionary reasoning Drift, Gene Flow and Competing Explanations Sixteen flies bred each generation, yet the flies drifted as if there were only nine. Why?
Unit 2 · Genomes, development and diversification
- Unit 2: Genomes, development and diversification Molecular Evolution Two species left no fossil of their split. Can their genes still tell you when it happened?
- Unit 2: Genomes, development and diversification Evolution of Development Some lake sticklebacks have almost no pelvis, yet their Pitx1 protein is unchanged. Where did the change happen?
- Unit 2: Genomes, development and diversification Speciation Two monkeyflowers can be crossed by hand. Why do they almost never exchange genes in the wild?
- Unit 2: Genomes, development and diversification History of Life and Macroevolution The oldest fossils tell you when life existed by, never when it began.
- Unit 2: Genomes, development and diversification Human Evolutionary History A face from Morocco, found with flints heated 315,000 years ago, looks like ours. Its braincase does not.
- Unit 2: Genomes, development and diversification Life Histories and Evolutionary Trade-offs Strap 3 grams to a skylark and it raises fewer chicks. Nothing was taken from its food. Where did the chicks go?
Unit 3 · Environments and populations
- Unit 3: Environments and populations Climate, Biomes and Environmental Variation Earth is closest to the Sun in early January. So why is January winter in the north?
- Unit 3: Environments and populations Distributions, Niches and Tolerances A dune plant planted 60 km past its own range edge more than tripled in number. So what was stopping it?
- Unit 3: Environments and populations Demography and Survivorship If 40% of banded birds do not come back next year, did 40% of them die?
- Unit 3: Environments and populations Population Growth and Regulation A population with a per-capita growth rate of 0.2 per day does not add the same number each day. Why does growth slow down at all?
- Unit 3: Environments and populations Movement and Spatial Populations Three visits, no toads heard. Is the pond empty?
Unit 4 · Interactions and communities
- Unit 4: Interactions and communities Competition Remove one barnacle species from a Scottish shore and the other survives lower down. What was holding it back?
- Unit 4: Interactions and communities Predation and Community Effects Keep one species of sea star off a patch of shore and the number of species there falls from 15 to 8. Why?
- Unit 4: Interactions and communities Mutualism, Parasitism and Coevolution The same root fungus can help a plant in poor soil and cost it in rich soil. Which is it?
- Unit 4: Interactions and communities Diversity, Disturbance and Succession Two plots hold the same four species. Can one be more diverse than the other?
- Unit 4: Interactions and communities Island Biogeography Empty an island of every insect and spider. How many species come back, and are they the same ones?
Unit 5 · Ecosystem processes
- Unit 5: Ecosystem processes Energy Flow and Productivity Plants often respire about half of what they fix. Where does the other half go?
- Unit 5: Ecosystem processes Nutrient Cycling Cut a forest and its stream starts carrying away nitrogen that never left before. Why?
- Unit 5: Ecosystem processes Biodiversity and Ecosystem Function In a decade-long Minnesota experiment, richer plots varied less from year to year, while the species inside them varied more.
Unit 6 · Global change and decisions
- Unit 6: Global change and decisions Global Change Across Scales If a mountain warms, how fast does a species' comfortable temperature move uphill, and does the species keep up?
- Unit 6: Global change and decisions Conservation and Restoration In 1995, eight female pumas from Texas were released into the Florida panther population. What did that change, and how would you know?
- Unit 6: Global change and decisions Integrative Evidence Workshop Twenty negative PCR wells from one pond. Is the newt gone?