Chapt03 Lecture

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  • EVOLUTION: What are the mechanisms that promote the great variety of species on earth and that determine which species will survive in one environment but not another? SPECIES INTERACTIONS: We will look at the interactions within and between species that affect their success and shape biological communities. BIOLOGICAL COMMUNITIES: No species is an island. It always lives with other species in a biological community in a particular environment.
  • Chapt03 Lecture

    1. 1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 3 Lecture Outline
    2. 2. Learning Outcomes After studying this chapter, you should be able to answer the following questions: <ul><li>• How does species diversity arise? </li></ul><ul><li>• Why do species live in different locations? </li></ul><ul><li>• How do interactions among species affect their fates and that of communities? </li></ul><ul><li>• If a species has unlimited growth potential, why doesn’t it fi ll the earth? </li></ul><ul><li>• What special properties does a community of species have, and why are they </li></ul><ul><li>important? </li></ul><ul><li>• What is the relationship between species diversity and community stability? </li></ul><ul><li>• What is disturbance, and how does it affect communities? </li></ul>3-
    3. 3. 3.1 Evolution Leads to Diversity <ul><li>Natural selection and adaptation modify species </li></ul><ul><ul><li>Adaptation, the acquisition of traits that allow a species to survive in its environment, is one of the most important concepts in biology. </li></ul></ul><ul><ul><li>The process of better-selected individuals passing their traits to the next generation is called natural selection. </li></ul></ul>3-
    4. 4. The ecological niche is a species’ role and environment <ul><li>Habitat describes the place or set of environmental conditions in which a particular organism lives. </li></ul><ul><li>Ecological niche, describes both the role played by a species in a biological community and the total set of environmental factors that determine a species distribution. </li></ul>3-
    5. 5. Niches: generalists & specialists <ul><li>Generalists have a broad niche, like cockroaches. </li></ul><ul><li>Specialists have narrow niches, like giant pandas. </li></ul>3-
    6. 6. Competitive exclusion principle & Resource partitioning 3-
    7. 7. The competitive exclusion principle 3-
    8. 8. Speciation <ul><li>The development of a new species is called speciation. </li></ul><ul><li>Geographic isolation results in allopatric speciation —species arise in non-overlapping geographic locations . </li></ul><ul><li>Behavioral isolation results in sympatric speciation —species arise in the same location as the ancestor species. </li></ul>3-
    9. 9. Directional, stabilizing, and disruptive selection 3-
    10. 10. Geographic isolation is a mechanism in allopatric speciation. 3-
    11. 11. Taxonomy <ul><li>Taxonomy is the study of types of organisms and their relationships. </li></ul><ul><li>Genus and species compose binomials, Also called scientific or Latin names. </li></ul>3-
    12. 12. Taxonomy describes relationships among species <ul><li>With taxonomy you can trace how organisms have descended from common ancestors. </li></ul><ul><li>Taxonomic relationships among species are displayed like a family tree. </li></ul>3-
    13. 13. 3.2 Species Interactions Shape Communities of Species <ul><li>Competition is a type of antagonistic relationship within a biological community. </li></ul><ul><li>Organisms compete for resources that are in limited supply. </li></ul><ul><li>Competition among members of the same species is called intraspecific competition. </li></ul><ul><li>Competition between members of different species is called interspecific competition. </li></ul>3-
    14. 14. Predation affects species relationships <ul><li>Consumers include herbivores, carnivores, omnivores, scavengers, detritivores, and decomposers. </li></ul>3-
    15. 15. Some adaptations help avoid predation <ul><li>Toxic chemicals, body armor, extraordinary speed, and the ability to hide are a few strategies organisms use to protect themselves. </li></ul>3-
    16. 16. Coevolution <ul><li>The response of predator to prey and vice versa, over tens of thousands of years, produces physical and behavioral changes in a process known as coevolution. </li></ul><ul><li>Coevolution can be mutually beneficial: many plants and pollinators have forms and behaviors that benefit each other. </li></ul><ul><li>A classic case is that of fruit bats, which pollinate and disperse seeds of fruit-bearing tropical plants. </li></ul>3-
    17. 17. Prey Defense Mechanisms: Batesian & Mullerian mimicry 3-
    18. 18. Prey Defense Mechanisms: Camouflage 3-
    19. 19. Types of Symbiosis: Intimate relations among species 3-
    20. 20. Types of Symbiosis: Intimate relations among species <ul><li>Commensalism is a type of symbiosis in which one member clearly benefits and the other apparently is neither benefited nor harmed. </li></ul><ul><li>Mutualism is a type of symbiosis in which both members clearly benefit. </li></ul>3-
    21. 21. Keystone species <ul><li>A keystone species plays a critical role in a biological community </li></ul>3-
    22. 22. 3.3 The Growth of Species Populations <ul><li>Biotic potential— the amount of potential growth of a population with unrestrained biological reproduction. </li></ul><ul><li>Exponential (r) growth is population growth with no limits; it results in a “J” growth curve when graphed. </li></ul><ul><li>Logistic growth curves result from carrying capacity (K) limiting population growth; it results in a “S” shaped growth curve when graphed. </li></ul>3-
    23. 23. J curve of exponential growth 3-
    24. 24. Population cycles 3-
    25. 25. S curve of logistic growth 3-
    26. 26. Limits to population size <ul><li>Density-dependent, meaning as population size increases, the effect intensifies. With a larger population, there is an increased risk that disease or parasites will spread, or that predators will be attracted to the area. </li></ul><ul><li>Density-independent limits to population are often nonbiological, capricious acts of nature. A population is affected no matter what its size. </li></ul>3-
    27. 27. Species respond to limits differently: r- and K-selected species 3-
    28. 28. Survivorship curves 3-
    29. 29. 3.4 Properties of Communities Depend on Species Diversity <ul><li>Diversity and abundance </li></ul><ul><ul><li>Diversity is the number of different species per unit area. </li></ul></ul><ul><ul><li>Abundance refers to the number of individuals of a species in an area. </li></ul></ul>3-
    30. 30. Species patterns create community structure <ul><li>Boundaries of species populations and communities form patterns that fit together: </li></ul><ul><ul><li>(1) individuals and species are spaced throughout communities in different ways; </li></ul></ul><ul><ul><li>(2) the communities themselves are arranged over a large geographic area or landscape </li></ul></ul><ul><ul><li>(3) communities have relatively uniform interiors (“cores”) and also “edges” that meet. </li></ul></ul><ul><li>Community (or ecological) structure refers to these patterns of spatial distribution of individuals, species, and communities. </li></ul>3-
    31. 31. Individuals in communities are distributed in various ways <ul><li>Random patterns arise from random distribution of resources. </li></ul><ul><li>Uniform patterns usually arise from competition. </li></ul><ul><li>Cluster patterns help a species protect themselves. </li></ul>3-
    32. 32. Communities are distributed in patterns across a landscape <ul><li>Core habitat- a mostly uniform environment big enough to support nearly all the plants and animals that are typically found in that community. </li></ul><ul><li>Ecotone- or border between two communities, rich in species. </li></ul><ul><li>Edge effects- where communities meet, the environmental conditions blend and the species and microclimate of one community can penetrate the other. . </li></ul>3-
    33. 33. 3.5 Communities Are Dynamic and Change Over Time <ul><li>Climax community- The community that developed last and lasted the longest. </li></ul><ul><li>Primary succession- land that is bare of soil—a sandbar, mudslide, rock face, volcanic flow—is colonized by living organisms where none lived before. </li></ul><ul><li>Secondary succession -after a disturbance, if left undisturbed, a community will mature to a characteristic set of organisms. </li></ul><ul><li>Pioneer species -the first species to colonize a community in primary succession on land. </li></ul>3-
    34. 34. Practice Quiz <ul><li>1. Explain how tolerance limits to environmental factors determine distribution of a highly specialized species such as the saguaro cactus. </li></ul><ul><li>2. Productivity, diversity, complexity, resilience, and structure are exhibited to some extent by all communities and ecosystems. Describe how these characteristics apply to the ecosystem in which you live. </li></ul><ul><li>3. Define selective pressure and describe one example that has </li></ul><ul><li>affected species where you live. </li></ul><ul><li>4. Define keystone species and explain their importance in community structure and function. </li></ul><ul><li>5. The most intense interactions often occur between individuals </li></ul><ul><li>of the same species. What concept discussed in this chapter </li></ul><ul><li>can be used to explain this phenomenon? </li></ul>3-
    35. 35. Practice Quiz continued <ul><li>6. Explain how predators affect the adaptations of their prey. </li></ul><ul><li>7. Competition for a limited quantity of resources occurs in all </li></ul><ul><li>ecosystems. This competition can be interspecific or intraspecific. </li></ul><ul><li>Explain some of the ways an organism might deal with </li></ul><ul><li>these different types of competition. </li></ul><ul><li>8. Describe the process of succession that occurs after a forest </li></ul><ul><li>fire destroys an existing biological community. Why may </li></ul><ul><li>periodic fire be beneficial to a community? </li></ul><ul><li>9. Which world ecosystems are most productive in terms of biomass </li></ul><ul><li>( fig. 3.31 )? Which are least productive? What units are </li></ul><ul><li>used in this figure to quantify biomass accumulation? </li></ul><ul><li>10. Discuss the dangers posed to existing community members </li></ul><ul><li>when new species are introduced into ecosystems. </li></ul>3-

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