Intro to Ecology & the Biosphere Chapter 52

Ecology scientific study of the interactions between organisms and the environment an organism’s environment includes: – abiotic (non-living) components – biotic (living) components) focuses on 4 levels of biological organization: – populations – communities – ecosystems – biosphere

Subfields of Ecology organismal ecology – how an organism′s structure, physiology, and behavior meet the challenges posed by the environment population ecology – how factors affect the number of individuals of a particular species live in an area community ecology – how interactions such as predation, competition, & disease, as well as abiotic factors like disturbance, affect community structure & organization

Subfields of Ecology cont. ecosystem ecology focuses on energy flow and chemical cycling among the various biotic and abiotic components landscape ecology deals with arrays of ecosystems & how they are arranged in a geographic region focuses on the factors controlling exchanges of energy, materials, and organisms among the ecosystem patches making up a landscape or seascape

Global Distribution of Organisms a major factor contributing to the global distribution of organisms is dispersal: movement of individuals away from centers of high population density or from their area of origin limits to distribution include: accessibility of an area (ie: dispersal) behavior (ie: habitat selection) biotic factors (ie: predation, competition, parasitism, disease) abiotic factors (ie: temperature, water, sunlight, wind, soil structure/nutrients, fire, oxygen, salinity, etc.)

Climate major components: temperature, water, sunlight, & wind temperature & water have a major influence on the distribution of organisms climate patterns can be described on 2 scales: macroclimate = patterns on the global, regional, & local level microclimate = very fine patterns, such as those encountered by the community of organisms underneath a fallen log

Macroclimate Earth′s global climate patterns are determined largely by the input of solar energy & the planet′s movement in space – the sun′s warming effect on the atmosphere, land, & water establishes the temperature variations, cycles of air movement, and evaporation of water that are responsible for dramatic latitudinal variations in climate proximity to bodies of water, mountain ranges, & other topographic features affect regional & local climatic variations – contributes to the patchiness of the biosphere changing angle of the sun over the course of the year also affects local environments

Sun Intensity: Latitude Variations

Sun Intensity: Seasonal Variations

Air Circulation & Precipitation Patterns

Wind Patterns

Water Moderates Climate warm summer day

Mountains Affect Rainfall

Microclimate many features in the environment influence microclimates by casting shade, affecting evaporation from soil, & changing wind patterns

Biomes major types of ecological associations that occupy broad geographic regions of land or water

Aquatic Biomes – account for the largest part of the biosphere in terms of area freshwater & marine

Aquatic Biomes cont. many aquatic biomes are physically & chemically stratified communities are distributed according to depth of the water, degree of light penetration, distance from shore, and open water versus bottom

Terrestrial Biomes because there are latitudinal patterns of climate over Earth′s surface, there are also latitudinal patterns of biome distribution the impact of climate on the distribution of organisms can be seen in a climograph

Terrestrial Biomes most terrestrial biomes are named for major physical or climatic features and for their predominant vegetation – vertical stratification of vegetation provides many different habitats for animals – terrestrial biomes usually grade into each other, without sharp boundaries at an area called an ecotone

Major Terrestrial Biomes

AQUATIC BIOMES Distribution of life is affected by: LIGHT Temperature Oxygen Salinity Turbulence

Zones in lake- affect distribution of organisms

FRESHWATER BIOMES Oligotrophic Lake Eutrophic Lake River

Wetlands (top) and estuaries (bottom)

Zonation in the marine environment

Examples of marine biomes TIDE POOL: Intertidal CORAL REEF DEEP SEA VENT: Benthos

Black smoker

The distribution of major terrestrial biomes

Temperate grassland Distribution: mid-latitudes, mid continents Precipitation: seasonal, dry season/wet season Temperature: cold winters/hot summers Characteristics: Prairie grasses, fire-adapted, drought tolerant plants; many herbivores; deep fertile soil

Temperate grassland

Temperate deciduous forest Distribution: mid-latitudes, northern hemisphere Precipitation: adequate; summer rains, winter snow Temperature: moderate warm summer, cool winter Characteristics: many mammals, insects, birds, etc. deciduous trees; fertile soil

Temperate deciduous forest

Coniferous forests Distribution: high-latitude, northern hemisphere Precipitation: adequate to dry (temperate rain forest on coast) Temperature: cool year round Characteristics: conifers;diverse mammals, birds, insects, etc.

Coniferous forests

Tundra Distribution: arctic, high-latitude, northern hemisphere Precipitation: dry Temperature: cold year round Characteristics: permafrost, lichens and mosses, migrating animals & resident herbivores

Tundra

Tropical forests Distribution: equatorial Precipitation: very wet Temperature: always warm Characteristics: many plants and animals, canopy; thin, poor soil

Tropical forests

Savanna Distribution: equatorial Precipitation: seasonal, dry season/wet season Temperature: always warm Characteristics: fire-adapted, drought tolerant plants; herbivores; fertile soil

Savanna

Deserts Distribution: 30 o N and S latitude band Precipitation: very little Temperature: variable daily and seasonal; hot and cold Characteristics: sparse vegetation and animals, cacti, succulents, drought-tolerant; reptiles, insects, rodents, birds

Deserts

Chaparral Distribution: coastal mid-latitude Precipitation: seasonal, dry summer/rainy winter Temperature: hot summer/cool winter Characteristics: scrubby vegetation, drought-adapted, fire-adapted; herbivores, amphibians, birds, insects

Chaparral

Threats to Ecosystem Stability Introduced Alien and Invasive Species