Ecology and the Biosphere Chapter 52 ~ An Introduction to Ecology and the Biosphere I am the Lorax. I speak for the trees. I speak for the trees, for the trees have no tongues.

Overview: Ecology These interactions Ecology is the study of interactions between organisms and the environment These interactions Determine both the distribution of organisms and their abundance

Ecology Is an enormously complex and exciting area of biology Reveals the richness of the biosphere Figure 50.1

Environmental components Affect the distribution and abundance of organisms Kangaroos/km2 > 20 10–20 5–10 1–5 0.1–1 < 0.1 Limits of distribution Climate in northern Australia is hot and wet, with seasonal drought. Red kangaroos occur in most semiarid and arid regions of the interior, where precipitation is relatively low and variable from year to year. Southeastern Australia has a wet, cool climate. Southern Australia has cool, moist winters and warm, dry summers. Tasmania Figure 50.2

Ecology Components: •abiotic~nonliving chemical & physical factors •biotic~living factors Population~group of individualsof the same species in a particular geographical area Community~assemblage of populations of different species Ecosystem~all abiotic factors and the community of species in an area Rachel Carson, 1962, Silent Spring

Abiotic factors Biosphere~the sum of all the planet’s ecosystems Biome~ areas of predominant flora and fauna Temperature Water Sunlight Wind Rocks & Soil Periodic disturbances Ecotone: biome grading areas

Dispersal and Distribution Is the movement of individuals away from centers of high population density or from their area of origin Contributes to the global distribution of organisms

Interactions between organisms and the environment limit the distribution of species Biogeography Provides a good starting point for understanding what limits the geographic distribution of species Species absent because Yes No Dispersal limits distribution? Behavior limits distribution? Biotic factors (other species) limit distribution? Abiotic factors limit distribution? Area inaccessible or insufficient time Habitat selection Predation, parasitism, competition, disease Water Oxygen Salinity pH Soil nutrients, etc. Temperature Light Soil structure Fire Moisture, etc. Chemical factors Physical Figure 50.6

Behavior and Habitat Selection Some organisms Do not occupy all of their potential range Species distribution May be limited by habitat selection behavior

Species Transplants Species transplants Include organisms that are intentionally or accidentally relocated from their original distribution Can often disrupt the communities or ecosystems to which they have been introduced

Slide by Kim Foglia

PROBLEMS CAUSED BY ZEBRA MUSSELS Clog power plant and public water intakes and pipes, costing taxpayers millions of dollars · Damage boat engines · Blanket shorelines with their sharp shells and foul smell · Consume available food for native species and smother native mussels · Threaten water-based recreational activities http://en.wikipedia.org/wiki/Zebra_mussel

Varying combinations of both biotic and abiotic factors Abiotic and biotic factors influence the structure and dynamics of aquatic biomes Varying combinations of both biotic and abiotic factors Determine the nature of Earth’s many biomes Biomes Are the major types of ecological associations that occupy broad geographic regions of land or water

The examination of biomes will begin with Earth’s aquatic biomes Tropic of Cancer Equator 30S Continental shelf Lakes Coral reefs Rivers Oceanic pelagic zone Estuaries Intertidal zone Abyssal zone (below oceanic pelagic zone) Key Tropic of Capricorn Figure 50.15

Aquatic biomes Account for the largest part of the biosphere in terms of area Can contain fresh or salt water Oceans Cover about 75% of Earth’s surface Have an enormous impact on the biosphere

Freshwater biomes Littoral zone~ shallow, well-lit waters close to shore Limnetic zone~ well-lit, open water farther from shore Profundal zone~ deep, aphotic waters Lake classification: •oligotrophic~ deep, nutrient poor •eutrophic~ shallow, high nutrient content •mesotrophic~ moderate productivity Wetland~ area covered with water Estuary~ area where freshwater merges with ocean

Marine biomes Intertidal zone~ area where land meets water Neritic zone~ shallow regions over continental shelves Oceanic zone~ very deep water past the continental shelves Pelagic zone~ open water of any depth Benthic zone~ seafloor bottom Abyssal zone~ benthic region in deep oceans

Four major abiotic components make up climate Climate largely determines the distribution and structure of terrestrial biomes Four major abiotic components make up climate Temperature, water, sunlight, and wind Climate Is particularly important in determining why particular terrestrial biomes are found in certain areas

The distribution of major terrestrial biomes Tropic of Cancer Equator Capricorn 30S Key Tropical forest Savanna Desert Chaparral Temperate grassland Temperate broadleaf forest Coniferous forest Tundra High mountains Polar ice Figure 50.19

Tropical forests~ equator; most complex; constant temperature and rainfall; canopy Savanna~ tropical grassland with scattered trees; occasional fire and drought; large herbivores Desert~ sparse rainfall (<30cm/yr) Chaparral~ spiny evergreens at midlatitudes along coasts Temperate grassland~ all grasses; seasonal drought, occasional fires; large mammals Temperate deciduous forest~ midlatitude regions; broad-leaf deciduous trees Coniferous forest~ cone-bearing trees Tundra~ permafrost; very little precipitation