CHAPTER 2

EVOLUTION AND ECOLOGY

2.1 Darwin’s Voyage on HMS Beagle

The Origin of Species by Means of Natural Selection

30 years of studyHMS BeagleGalapagos Islands

2.2 Darwin’s Evidence

Principles of Geology, by Charles Lyellfossil recordliving animal similaritiesembryologynonfunctional partsplants from cabbage

See Table 2.1

Fossils

Geographical Distribution

Oceanic Islands

2.3 Inventing the Theory of Natural Selection

Darwin and Malthus population size stays constant

Natural Selection Individuals that possess superior physical,

behavioral, or other attributes are more likely to survive than those not so well endowed.

Ex. Breeding domestic animals (pigeons)

Inventing the Theory

Darwin drafts his argument but waits 16 years to publish it.

Wallace has the same idea.Publication of Darwin’s Theory

The Descent of Man

2.4 The Beaks of Darwin’s Finches

See Figure 2.11The importance of the beak.Was Darwin wrong?A Closer Look

See Figure 2.13 The Measurement of beaks in Geospiza fortis.

Darwin was right after all.

2.5 Clusters of Species

Adaptive radiation 1. Ground finches 2. Tree finches 3. Warbler finch 4. Vegetarian finch

See Figure 2.14

2.6 Hawaiian Drosophila

Unique morphological and behavioral traitsScaptomyza and DrosophilaLarvae have specialized niches. Adaptive radiation

2.7 Lake Victoria Chichlid Fishes

Recent radiationChichlid diversityAbrupt extinction

2.8 New Zealand Alpine Buttercups

Adaptive radiation by periodic isolationRananculus species have invaded five

habitats, receded to isolate mountain habitats, and reformed links again.

See Figure 2.18

2.9 What is Ecology?

The study of how the organisms that live in a place interact with their physical world.

Levels of Ecological Organization Populations Communities Ecosystems Biomes

Population, community, or systems ecologists

2.10 Ecosystems

ENERGY FLOWS THROUGH ECOSYSTEMS

FOOD CHAINS SOLAR ENERGY PRODUCERS CONSUMERS (herbivores, carnivores) DECOMPOSERS

Materials Cycle Within Ecosystems

Minerals are recycled from organism to organism.

Major Ecosystems = Biomes

Rainfall and temperature are important factors.

Draw food chains for different biomes. See Fig. 2.20

POPULATIONS AND HOW THEY GROW

2.11 Patterns of Population Growth

Innate capacity for increase or biotic potential

Realized rate of population increaseImmigrants Emigrantsr = (birth = immigration)- (death +

emigration)

Exponential Growth

Population growth rate = rNr = rate of population increaseN = number of individualsNotice the J-shaped curve

Carrying Capacity

List factors needed by a populationpopulation growth rate = rN (K - N) Krate x number of population x carrying

capacityRead sectionSigmoid growth curve

Life History Strategies

R = exponential growthK = slow population growthMosquitoes reproduce fast = r-selected life

history and J curveElephants reproduce slowly = a K-selected

life history and a slow incline

2.11 Population growth is limited by the ability of the environment to support the population. Organisms in transient environments are often adapted to reproduce rapidly, while those in stable environments tend to reproduce more slowly.

2.12 Human Populations

Humans have K-selected lifestyles.A stable population is now doubling

rapidly.See Figure 2.25

The Advent of Exponential Human Population Growth

The population may double in forty years.

Population Pyramids

See Figure 2.26 - Mexico’s populationSee Figure 2.27 - Population pyramidsCompare developed countries to

underdeveloped countriesLook at Table 2.2

An Uncertain Future

Population growth is a challenge to the earth.There will be an uneven population growth

rate among countries. See Fig. 2.28The wealth gap becomes larger.Developed countries use too many resources.Birth and death rates have changed.