1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 50 An Introduction to Ecology and the Biosphere

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Overview: The Scope of Ecology (1)Ecology is the scientific study of the interactions between organisms and the environment These interactions determine distribution of organisms and their abundance Ecology reveals the richness of the biosphere (2) Three questions – Where they live? Why do they live where they do? How many are there?

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4. Concept 50.1: Ecology is the study of interactions between organisms and the environment Ecology has a long history as a descriptive science It is also a rigorous experimental science

5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ecology and Evolutionary Biology Events that occur in ecological time affect life on the scale of evolutionary time (1) Environmental factors interacting with variation within populations can cause evolutionary change

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Organisms and the Environment (2)The environment of any organism includes: – Abiotic, or nonliving, components – Biotic, or living, components All the organisms that are part of the individual’s environment are collectively called the biota Environmental components affect the distribution and abundance of organisms

7. LE 50-2 Kangaroos/km 2 > 20 10–20 5–10 1–5 0.1–1 < 0.1 Limits of distribution Tasmania

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ecologists use observations and experiments to test explanations for the distribution and abundance of species

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Subfields of Ecology Organismal ecology studies how an organism’s structure, physiology, and (for animals) behavior meet environmental challenges

10. LE 50-3a Organismal ecology

11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Population ecology focuses on factors affecting how many individuals of a species live in an area

12. LE 50-3b Population ecology

13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Community ecology deals with the whole array of interacting species in a community

14. LE 50-3c Community ecology

15. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ecosystem ecology emphasizes energy flow and chemical cycling among the various biotic and abiotic components

16. LE 50-3d Ecosystem ecology

17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Landscape ecology deals with arrays of ecosystems and how they are arranged in a geographic region

18. LE 50-3e Landscape ecology

19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The biosphere is the global ecosystem, the sum of all the planet’s ecosystems

20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ecology and Environmental Issues Ecology provides the scientific understanding underlying environmental issues Rachel Carson is credited with starting the modern environmental movement

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22. Most ecologists follow the precautionary principle regarding environmental issues It states that humans need to be concerned with how their actions affect the environment (6) an ounce of prevention is worth a pound of cure.

23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 50.2: Interactions between organisms and the environment limit the distribution of species Ecologists have long recognized global and regional patterns of distribution of organisms within the biosphere Many naturalists, such as Darwin and Wallace began to identify broad patterns of distribution by naming biogeographic realms Now associate these biogeographic realms with patterns of continental drift.

24. LE 50-5 Tropic of Cancer (23.5°N) Equator (23.5°S) Tropic of Capricorn Neotropical Ethiopian Australian Oriental Nearctic Palearctic

25. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biogeography is a good starting point for understanding what limits geographic distribution of species (1) study of the past and present distribution of individual species.

26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Dispersal and Distribution (2) Dispersal is movement of individuals away from centers of high population density or from their area of origin Dispersal contributes to global distribution of organisms

27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Behavior and Habitat Selection (3) Some organisms do not occupy all of their potential range Individuals seem to avoid certain habitats even when they are suitable. Species distribution may be limited by habitat selection behavior ie: some insects only lay eggs on certain plants even though larvae can feed on different kinds.

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biotic Factors Biotic factors that affect the distribution of organisms may include: – Negative interactions with other species – Predation – Parasitism – disease – Competition – Or absence of other species (ie pollinator)

29. LE 50-8 August 1982 Sea urchin August 1983 February 1983 February 1984 Both limpets and urchins removed Limpet 100 80 60 40 20 0 Only urchins removed Only limpets removed Control (both urchins and limpets present) Seaweed cover (%)

30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Abiotic Factors Abiotic factors affecting distribution of organisms: – Temperature – Water – Sunlight – Wind – Rocks and soil

31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Temperature Environmental temperature is an important factor in distribution of organisms because of its effects on biological processes at the cellular level – Cells freeze at temperature below 0 o C – Proteins denature at temperature above 45 o C

32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Water Water availability in habitats is another important factor in species distribution Fresh vs salt water (osmoregulation) Land organisms face disiccation

33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sunlight Light intensity and quality affects photosynthesis – Shading creates competition for sunlight – Aquatic-limited by depth Light is also important to development and behavior of organisms sensitive to photoperiod

34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Wind Wind amplifies effects of temperature by increasing heat loss from evaporation and convection Wind can change morphology of plants

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36. Rocks and Soil Many characteristics of soil limit distribution of plants and thus the animals that feed upon them: – Physical structure – pH – Mineral composition

37. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Climate (6)Four major abiotic components of climate: temperature, water, sunlight, and wind Climate is the prevailing weather in an area Macroclimate consists of patterns on the global, regional, and local level Microclimate consists of very fine patterns, such as those encountered by the community of organisms underneath a fallen log

38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Global Climate Patterns Global climate patterns are determined largely by solar energy and the planet’s movement in space

39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Sunlight intensity plays a major part in determining the Earth’s climate patterns

40. LE 50-10a North Pole 60°N Low angle of incoming sunlight Sunlight directly overhead at equinoxes Tropic of Cancer 60°S South Pole 30°N Atmosphere 30°S Tropic of Capricorn 0° (equator)

41. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Seasonal variations of light and temperature increase steadily toward the poles

42. LE 50-10b June solstice: Northern Hemisphere tilts toward sun; summer begins in Northern Hemisphere; winter begins in Southern Hemisphere. 30°N 30°S 0° (equator) 60°N Constant tilt of 23.5° September equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness. December solstice: Northern Hemisphere tilts away from sun; winter begins in Northern Hemisphere; summer begins in Southern Hemisphere. March equinox: Equator faces sun directly; neither pole tilts toward sun; all regions on Earth experience 12 hours of daylight and 12 hours of darkness.

43. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Global air circulation and wind patterns play major roles in determining climate patterns

44. LE 50-10c 30°N 30°S 0° (equator) 60°N Descending dry air absorbs moisture 60°S Ascending moist air releases moisture Descending dry air absorbs moisture Tropics Arid zone Arid zone 0° 30° 23.5° 30° 23.5°

45. LE 50-10d 30°N 30°S 0° (equator) 60°N 60°S Arctic Circle Antarctic Circle Westerlies Northeast trades Doldrums Westerlies Southeast trades

46. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Regional, Local, and Seasonal Effects on Climate Various features of the landscape contribute to local variations in climate Seasonal variation also influences climate

47. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bodies of Water Oceans and their currents and large lakes moderate the climate of nearby terrestrial environments

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49. Mountains have a significant effect on – The amount of sunlight reaching an area – Local temperature – Rainfall South facing slopes in NA receive more sunlight than North facing slopes and are warmer and drier. Mountains

50. LE 50-12 Pacific Ocean Wind direction Coast Range Sierra Nevada East

51. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Seasonality The angle of the sun leads to many seasonal changes in local environments Lakes are sensitive to seasonal temperature change and experience seasonal turnover

52. LE 50-13 Winter O 2 (mg/L) 12 Lake depth (m) 24 16 8 840 O 2 concentration High (>8 mg/L) Medium (4–8 mg/L) Low (<4 mg/L) O 2 (mg/L) 12 Lake depth (m) 24 16 8 840 O 2 (mg/L) 12 Lake depth (m) 24 16 8 840 O 2 (mg/L) 12 Lake depth (m) 24 16 8 840 Autumn Summer Spring Thermocline 4°C 5° 6° 8° 18° 20° 22° 4°C 4° 4°C 4° 4°C 4° 2° 0° 4°

53. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Microclimate Microclimate is determined by fine-scale differences in abiotic factors

54. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Long-Term Climate Change One way to predict future global climate change is to study previous changes

55. LE 50-14 4.5°C warming over next century 6.5°C warming over next century Current range Predicted range Overlap

56. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 50.3: Abiotic and biotic factors influence the structure and dynamics of aquatic biomes Varying combinations of biotic and abiotic factors determine the nature of biomes Biomes are the major ecological associations that occupy broad geographic regions of land or water

57. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Aquatic biomes account for the largest part of the biosphere in terms of area They can contain fresh water or salt water Oceans cover about 75% of Earth’s surface and have an enormous impact on the biosphere

58. LE 50-15 Continental shelf Tropic of Capricorn 30°S Tropic of Cancer Equator 30°N Lakes Coral reefs Key Rivers Oceanic pelagic zone Estuaries Intertidal zone Abyssal zone (below oceanic pelagic zone)

59. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Many aquatic biomes are stratified into zones or layers defined by light penetration, temperature, and depth

60. LE 50-16a Zonation in a lake Benthic zone Pelagic zone Aphotic zone Photic zone Littoral zone Limnetic zone

61. LE 50-16b Marine zonation Benthic zone Pelagic zone Aphotic zone Photic zone Oceanic zone Neritic zone Intertidal zone Continental shelf 0 200 m 2,500–6,000 m Abyssal zone (deepest regions of ocean floor)

62. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Major aquatic biomes: – Lakes – Wetlands – Streams and rivers – Estuaries – Intertidal zones – Oceanic pelagic biome – Coral reefs – Marine benthic zone

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73. Concept 50.4: Climate largely determines the distribution and structure of terrestrial biomes Climate is very important in determining why terrestrial biomes are found in certain areas

74. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Climate and Terrestrial Biomes Climate has a great impact on the distribution of organisms, as seen on a climograph

75. LE 50-18 Temperate grassland Tropical forest Desert Temperate broadleaf forest Coniferous forest Arctic and alpine tundra Annual mean precipitation (cm) Annual mean temperature (°C) 400 300 200 100 30 15 0 –15

76. LE 50-19 Temperate grassland Tropic of Cancer 30°N Tropic of Capricorn 30°S Equator Tropical forest Desert Savanna Key Chaparral Coniferous forest Temperate broadleaf forest Tundra High mountains Polar ice

77. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings General Features of Terrestrial Biomes Terrestrial biomes are often named for major physical or climatic factors and for vegetation Stratification is a key feature of terrestrial biomes Terrestrial biomes usually grade into each other, without sharp boundaries The area of intergradation, called an ecotone, may be wide or narrow

78. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Major terrestrial biomes: – Tropical forest – Desert – Savanna – Chaparral – Temperate grassland – Coniferous forest – Temperate broadleaf forest – Tundra

79. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings