2

2.1 Darwin's Voyage on HMS Beagle

2.2 Darwin's Evidence

2.3 Inventing the Theory of Natural Selection

2.9 What is Ecology?

2.10 Ecosystems

2.4 The Beaks of Darwin's Finches

2.5 Clusters of Species

2.6 Hawaiian Drosophila

2.7 Lake Victoria Cichlid Fishes

2.8 New Zealand Alpine Buttercups

2.11 Patterns of Population Growth

2.12 Human Populations

Animations
(Animation Requirements)

• Evolutionary History of Equus
• Microevolution
• Exponential Population Growth
• Stages of Population Growth
• U.S. Age Distributions, 1910, 1960 and 2010 (projected)
• Age Distributions for MDCs and LDCs
• World Population Growth, 1750 - 2150
• Resource Consumption for MDCs and LDCs

Darwin's Critics. While Darwin's theory of evolution by natural selection is almost universally accepted by scientists, it has proven quite a bit more controversial among the general public. Objections to the teaching of evolution in American public schools have focused on a family of arguments with which every student of biology should become familiar. Many of the criticisms of evolution were raised in the years soon after Darwin's publication of in the Origin of the Species. More recent criticisms doubt that evolution could produce the complexity we see at the cellular and molecular level.

1. 140 Years without Darwin are enough.
2. Answering evolution's critics.
3. Keeping Darwin out of schoolrooms.
4. Darwinism at the cellular level.
5. Darwin and charter schools.

Darwin and Evolution
Evolution is the core of the science of biology. The theory that evolution occurs because of natural selection was advanced by two British naturalists, Charles Darwin and Alfred Wallace, in 1859. The story of how Darwin and Wallace independently came to this key insight says a great deal about the role of observation in science, and the important role played by careful reasoning. Darwin, just out of college at the age of 22, spent five years as a naturalist on a ship that explored the coast of South America, including a group of volcanic islands, the Galápagos Islands. He spent little time on the ship, instead trekking for 2 years in Argentina and 1-1/2 years in Chile, before sailing around the world to return to England in 1836. It was more than 20 years before Darwin, stimulated by Wallace's similar conclusions after years exploring southeastern Asia, published his book On The Origin of Species. There he presents an enormous body of evidence supporting his theory of evolution by natural selection. Perhaps Darwin's greatest contribution to biology is that he converted evolution from a hypothesis to a documented observation. However controversial his theory among the general public, it is supported by overwhelming evidence, and is universally accepted by biologists.

Why Do Tropical Songbirds Lay Fewer Eggs?
British ornithologist Reginald Moreau made an interesting observation in 1944, that songbirds in the tropics lay fewer eggs than their counterparts at higher latitudes. This was particularly interesting because one would expect that natural selection would maximize evolutionary fitness--that is, songbirds the world over should have evolved to produce as many eggs as possible. Why don't the birds living in the tropics produce a maximum number of eggs? David Lack, a colleague of Moreau's, put forth an argument that natural selection will indeed tend to maximize reproduction rates but only to the greatest level possible within the limits of resources. If there are fewer resources available, birds will lay fewer eggs. This idea was tested by Mark Boyce (now at the University of Alberta, Edmonton) using data collected on the nesting habits and clutch sizes (the number of eggs laid in a nest) of the Great Tit in Oxford, England. A very complete field study was conducted over a 22-year period. The clutch sizes of 4,489 nests were counted, and the number of offspring surviving to the next year determined, to look for the predicted correlation.