Transcript CHAPTER 2
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 study HMS Beagle Galapagos Islands 2.2 Darwin’s Evidence Principles of Geology, by Charles Lyell fossil record living animal similarities embryology nonfunctional parts plants 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 2.11 The 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. 2. 3. 4. Ground finches Tree finches Warbler finch Vegetarian finch See Figure 2.14 2.6 Hawaiian Drosophila Unique morphological and behavioral traits Scaptomyza and Drosophila Larvae have specialized niches. Adaptive radiation 2.7 Lake Victoria Chichlid Fishes Recent radiation Chichlid diversity Abrupt extinction 2.8 New Zealand Alpine Buttercups Adaptive radiation by periodic isolation Rananculus 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 increase Immigrants Emigrants r = (birth = immigration)- (death + emigration) Exponential Growth Population growth rate = rN r = rate of population increase N = number of individuals Notice the J-shaped curve Carrying Capacity List factors needed by a population population growth rate = rN (K - N) K rate x number of population x carrying capacity Read section Sigmoid growth curve Life History Strategies R = exponential growth K = slow population growth Mosquitoes reproduce fast = r-selected life history and J curve Elephants 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 population See Figure 2.27 - Population pyramids Compare developed countries to underdeveloped countries Look 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. 2.28 The wealth gap becomes larger. Developed countries use too many resources. Birth and death rates have changed.