1. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Chapter 52 An Introduction to Ecology and the Biosphere

2. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings You will be able to: 1.Explain how dispersal may contribute to a species’ distribution 2.Distinguish between the following pairs of terms: potential and actual range, biotic and abiotic factors, macroclimate and microclimate patterns

3. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 1.Define the following terms: photic zone, aphotic zone, benthic zone, abyssal zone, thermal stratification, thermocline, seasonal turnover, climograph, disturbance 2.List and describe the characteristics of the major terrestrial biomes 3.Compare the vertical layering of a forest and grassland

4. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Overview: The Scope of Ecology 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

5. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 52.2: 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 Biogeography is a good starting point for understanding what limits geographic distribution of species Ecologists recognize two kinds of factors that determine distribution: biotic, or living factors, and abiotic, or nonliving factors

6. Fig. 52-6 Why is species X absent from an area? Does dispersal limit its distribution? Does behavior limit its distribution? Area inaccessible or insufficient time Yes No Yes Habitat selection Do biotic factors (other species) limit its distribution? Predation, parasitism, competition, disease Do abiotic factors limit its distribution? Chemical factors Physical factors Water Oxygen Salinity pH Soil nutrients, etc. Temperature Light Soil structure Fire Moisture, etc.

7. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Dispersal and Distribution 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 Natural range expansions show the influence of dispersal on distribution

8. Fig. 52-7 Current 1966 1970 1965 1960 1961 1958 1951 1943 1937 1956 1970

9. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Species Transplants Species transplants include organisms that are intentionally or accidentally relocated from their original distribution Species transplants can disrupt the communities or ecosystems to which they have been introduced

10. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Behavior and Habitat Selection Some organisms do not occupy all of their potential range Species distribution may be limited by habitat selection behavior

11. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Biotic Factors Biotic factors that affect the distribution of organisms may include: – Interactions with other species – Predation – Competition

12. Fig. 52-8 RESULTS Sea urchin 100 80 60 40 20 0 Limpet Seaweed cover (%) Both limpets and urchins removed Only urchins removed Only limpets removed Control (both urchins and limpets present) August 1982 August 1983 February 1983 February 1984

13. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Abiotic Factors Abiotic factors affecting distribution of organisms include: – Temperature – Water – Sunlight – Wind – Rocks and soil Most abiotic factors vary in space and time

14. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Temperature Environmental temperature is an important factor in distribution of organisms because of its effects on biological processes Cells may freeze and rupture below 0°C, while most proteins denature above 45°C Mammals and birds expend energy to regulate their internal temperature

15. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Water Water availability in habitats is another important factor in species distribution Desert organisms exhibit adaptations for water conservation

16. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Salinity Salt concentration affects water balance of organisms through osmosis Few terrestrial organisms are adapted to high- salinity habitats

17. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Sunlight Light intensity and quality affect photosynthesis Water absorbs light, thus in aquatic environments most photosynthesis occurs near the surface In deserts, high light levels increase temperature and can stress plants and animals

18. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Rocks and Soil Many characteristics of soil limit distribution of plants and thus the animals that feed upon them: – Physical structure – pH – Mineral composition

19. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Climate Four major abiotic components of climate are temperature, water, sunlight, and wind The long-term prevailing weather conditions in an area constitute its climate 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

20. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Global Climate Patterns Global climate patterns are determined largely by solar energy and the planet’s movement in space Sunlight intensity plays a major part in determining the Earth’s climate patterns More heat and light per unit of surface area reach the tropics than the high latitudes

21. Fig. 52-10a Latitudinal Variation in Sunlight Intensity Low angle of incoming sunlight Sun directly overhead at equinoxes Low angle of incoming sunlight Atmosphere 90ºS (South Pole) 60ºS 30ºS 23.5ºS (Tropic of Capricorn) 0º (equator) 30ºN 23.5ºN (Tropic of Cancer) 60ºN 90ºN (North Pole) Seasonal Variation in Sunlight Intensity 60ºN 30ºN 30ºS 0º (equator) March equinox June solstice Constant tilt of 23.5º September equinox December solstice

22. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Global air circulation and precipitation patterns play major roles in determining climate patterns Warm wet air flows from the tropics toward the poles

23. Fig. 52-10d Global Air Circulation and Precipitation Patterns 60ºN 30ºN 0º (equator) 30ºS 60ºS Global Wind Patterns Descending dry air absorbs moisture Ascending moist air releases moisture Descending dry air absorbs moisture Arid zone Tropics Arid zone 0º 66.5ºN (Arctic Circle) 60ºN 30ºN 0º (equator) 30ºS 60ºS 66.5ºS (Antarctic Circle) Westerlies Northeast trades Doldrums Southeast trades Westerlies 23.5º 30º 23.5º 30º

24. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Air flowing close to Earth’s surface creates predictable global wind patterns Cooling trade winds blow from east to west in the tropics; prevailing westerlies blow from west to east in the temperate zones

25. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Bodies of Water The Gulf Stream carries warm water from the equator to the North Atlantic Oceans and their currents and large lakes moderate the climate of nearby terrestrial environments

26. Fig. 52-11 Labrador current Gulf stream Equator Cold water Warm water

27. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings During the day, air rises over warm land and draws a cool breeze from the water across the land As the land cools at night, air rises over the warmer water and draws cooler air from land back over the water, which is replaced by warm air from offshore

28. Fig. 52-12 Warm air over land rises. 1 2 3 4 Air cools at high elevation. Cool air over water moves inland, replacing rising warm air over land. Cooler air sinks over water.

29. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Mountains Mountains have a significant effect on – The amount of sunlight reaching an area – Local temperature – Rainfall Rising air releases moisture on the windward side of a peak and creates a “rain shadow” as it absorbs moisture on the leeward side

30. Fig. 52-13 Wind direction Mountain range Leeward side of mountain Ocean

31. Copyright © 2008 Pearson Education, Inc., publishing as Pearson 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

32. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Long-Term Climate Change Global climate change will profoundly affect the biosphere One way to predict future global climate change is to study previous changes As glaciers began retreating 16,000 years ago, tree distribution patterns changed As climate changes, species that have difficulty dispersing may have smaller ranges or could become extinct

33. Fig. 52-14 Current range Predicted range Overlap (a) 4.5ºC warming over next century (b) 6.5ºC warming over next century

34. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Concept 52.4: The structure and distribution of terrestrial biomes are controlled by climate and disturbance Climate is very important in determining why terrestrial biomes are found in certain areas Biome patterns can be modified by disturbance such as a storm, fire, or human activity

35. Fig. 52-19 Tropical forest Savanna Desert Chaparral Temperate grassland Temperate broadleaf forest Northern coniferous forest Tundra High mountains Polar ice 30ºN Tropic of Cancer Equator Tropic of Capricorn 30ºS

36. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Climate and Terrestrial Biomes Climate has a great impact on the distribution of organisms This can be illustrated with a climograph, a plot of the temperature and precipitation in a region Biomes are affected not just by average temperature and precipitation, but also by the pattern of temperature and precipitation through the year

37. Fig. 52-20 Tropical forest Temperate grassland Desert Temperate broadleaf forest Northern coniferous forest Arctic and alpine tundra Annual mean temperature (ºC) Annual mean precipitation (cm) 30 15 0 0 –15 100200 300 400

38. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings General Features of Terrestrial Biomes and the Role of Disturbance Terrestrial biomes are often named for major physical or climatic factors and for vegetation Terrestrial biomes usually grade into each other, without sharp boundaries The area of intergradation, called an ecotone, may be wide or narrow

39. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Vertical layering is an important feature of terrestrial biomes, and in a forest it might consist of an upper canopy, low-tree layer, shrub understory, ground layer of herbaceous plants, forest floor, and root layer Layering of vegetation in all biomes provides diverse habitats for animals Biomes are dynamic and usually exhibit extensive patchiness

40. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Terrestrial Biomes Terrestrial biomes can be characterized by distribution, precipitation, temperature, plants, and animals

41. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Tropical Forest In tropical rain forests, rainfall is relatively constant, while in tropical dry forests precipitation is highly seasonal Tropical forests are vertically layered and competition for light is intense Tropical forests are home to millions of animal species, including an estimated 5–30 million still undescribed species of insects, spiders, and other arthropods

42. Fig. 52-21a A tropical rain forest in Borneo

43. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Desert Precipitation is low and highly variable, generally less than 30 cm per year; deserts may be hot or cold Desert plants are adapted for heat and desiccation tolerance, water storage, and reduced leaf surface area Common desert animals include many kinds of snakes and lizards, scorpions, ants, beetles, migratory and resident birds, and seed-eating rodents; many are nocturnal

44. Fig. 52-21b A desert in the southwestern United States

45. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Savanna Savanna precipitation and temperature are seasonal Grasses and forbs make up most of the ground cover Common inhabitants include insects and mammals such as wildebeests, zebras, lions, and hyenas

46. Fig. 52-21c A savanna in Kenya

47. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Chaparral Chaparral climate is highly seasonal, with cool and rainy winters and hot dry summers The chaparral is dominated by shrubs, small trees, grasses, and herbs; many plants are adapted to fire and drought Animals include amphibians, birds and other reptiles, insects, small mammals and browsing mammals

48. Fig. 52-21d An area of chaparral in California

49. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Temperate Grassland Temperate grasslands are found on many continents Winters are cold and dry, while summers are wet and hot The dominant plants, grasses and forbs, are adapted to droughts and fire Native mammals include large grazers and small burrowers

50. Fig. 52-21e Sheyenne National Grassland in North Dakota

51. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Northern Coniferous Forest The northern coniferous forest, or taiga, extends across northern North America and Eurasia and is the largest terrestrial biome on Earth Winters are cold and long while summers may be hot

52. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The conical shape of conifers prevents too much snow from accumulating and breaking their branches Animals include migratory and resident birds, and large mammals

53. Fig. 52-21f Rocky Mountain National Park in Colorado

54. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Temperate Broadleaf Forest Winters are cool, while summers are hot and humid; significant precipitation falls year round as rain and snow A mature temperate broadleaf forest has vertical layers dominated by deciduous trees in the Northern Hemisphere and evergreen eucalyptus in Australia

55. Fig. 52-21g Great Smoky Mountains National Park in North Carolina

56. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Tundra Tundra covers expansive areas of the Arctic; alpine tundra exists on high mountaintops at all latitudes Winters are long and cold while summers are relatively cool; precipitation varies

57. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Permafrost, a permanently frozen layer of soil, prevents water infiltration Vegetation is herbaceous (mosses, grasses, forbs, dwarf shrubs and trees, and lichen) and supports birds, grazers, and their predators

58. Fig. 52-21h Denali National Park, Alaska, in autumn