Ecology Chapter 2: Principles of EcologyPrinciples of Ecology Chapter 3: Communities and BiomesCommunities and Biomes

Principles of Ecology 2-1: Organisms and EnvironmentOrganisms and Environment 2-2: Nutrition and Energy FlowNutrition and Energy Flow

Communities and Biomes 3-1: CommunitiesCommunities 3-2: BiomesBiomes

2-1: Organisms & the Environment Ecology: study of interactions between organisms and their environment Explains how organisms affect each other and the world they live in Environment can either be living or non-living

Non- living Environment Abiotic factors: the non-living parts of an organism’s environment Examples include air currents, temperature, moisture, light, and soil.

Living Environment Biotic factors: all the living organisms that inhabit an environment All organisms depend on others directly or indirectly

Abiotic or Biotic? Biotic

Abiotic or Biotic? Abiotic

Levels of Organization All organisms are organized into levels cells organism organ systems organs tissues

The interactions of the organism are then organized depending on complexity

1 st Level Organism –individual living thing that is made of cells, uses energy, reproduces, responds, grows, and develops –at this level species are studied species: group of similar organisms that can interbreed and produce fertile offspring

2 nd Level Population –A group of organisms that interbreed and live in the same place at the same time –Have to be same species to be a population

3 rd Level Community –all the interacting populations in a certain area at a certain time –change in one population may cause changes in the other populations Ex. hawks and mice

4 th Level Ecosystem –interacting populations in a community and the community’s abiotic factors –terrestrial or aquatic –subject to change Ex. forest, compost heap, pond

5 th Level Biosphere –the portion of Earth that supports life –extends from high atmosphere to bottom of oceans

Organism Community Ecosystem Population Biosphere

Organisms in Their Environment Habitat: place where an organism lives out its life –Ex. bottom of a stream Niche: all strategies and adaptations a species uses in its environment –organism’s way of life

Relationships Predation –predator seeks out and eats prey Ex. cheetah hunting down antelope –constant battle for survival preypredator

Relationships Symbiosis –close and permanent association between organisms of different species –they live together –helps maintain their survival –3 types of symbiosis

Symbiosis Mutualism –symbiotic relationship where both species benefit –Ex. Ants and Acacia Trees

Symbiosis Commensalism –symbiotic relationship where one species benefits and the other is neither harmed nor benefited –Ex. Clownfish and Sea Anemones

Symbiosis Parasitism –symbiotic relationship where one species benefits at the expense of the other –species that is harmed is called a host –Ex. Fleas and Animals

2-2: Nutrition & Energy Flow ultimate source of energy for all life (directly or indirectly) is the sun some convert sunlight into energy-- an organism that uses light energy to make their own food is a producer or autotroph plants

Obtaining Energy Producers then feed consumers –organism that cannot make its own food and feeds on other organisms; also called heterotroph Heterotrophs can be carnivoresherbivores or omnivores

Food Chains Matter and energy move through ecosystems from producers to consumers Some energy is also transferred to the environment as heat Food chain: –model showing how matter and energy move through an ecosystem –Nutrients and energy move from AutotrophHeterotrophDecomposer

Food Chains Arrows indicate direction energy is transferred Each organism represents a trophic level or a feeding step First level is always a producer Remaining levels are consumers and can be divided into different orders

Consumers Can Be: 1 st order heterotroph (primary consumers): feeds on plants grasshoppers, deer, mice 2 nd order heterotroph (secondary consumers): feeds on 1 st order heterotroph frogs, snakes, small birds, etc. 3 rd order heterotroph (tertiary consumers): feeds on 2 nd order heterotroph owls, coyotes, snakes, etc.

Food Webs Food chains only show one route of matter and energy transfer Ecosystems typically have more than one route –Ex. Snakes eat mice that eat producers, but also eat frogs that eat 1 st order consumers. So what is the snake, and how is energy transferred? Food web: shows all the possible feeding relationships at each trophic level in a community

Food Webs Represents a network of interconnected food chains

Ecological Pyramids another way to show how energy flows Energy pyramids show: –Only 10% of energy is available to next level –large # of producers to support small # of primary consumers –large # of primary consumers to support small # of secondary consumers 100% 0.1% 1% 10%

Cycles in Nature Matter is also transferred; does not disappear but is constantly cycled Three main elements that must move through an ecosystem are: –Water –Carbon –Nitrogen

Water Cycle

Carbon Cycle

Nitrogen Cycle

3-1: Communities What is a community? –all the populations in a certain area at a certain time Are all parts of the world suitable for every organism? –No

Limiting Factors any factor that restricts the number of individuals in a population affects an organism’s ability to survive in its environment Examples: water food predators temperature space sunlight soil

Tolerance range of factors under which an organism functions & survives Organisms absent Organisms infrequent Greatest number of organisms Organisms infrequent Organisms absent Zone of intolerance Zone of physiological stress Optimum range Zone of physiological stress Zone of intolerance Range of tolerance Population Lower limitUpper limit

Succession orderly, natural changes and species replacements that occur in communities over time occurs in stages; different species may be present at each stage 2 types –primary –secondary

Succession Primary –colonization of barren land by communities of organisms –takes place where there are no living organisms –first species to take hold are pioneer species –Example Lava destroys everything and forms new land Lichen begins growing—pioneer species

Succession Secondary –takes place after an existing community is disrupted in some way –occurs in areas that previously contained life and on land that still contains soil –Example Forest fires destroy communities, but soil is still available Species begin coming back

After some time, succession slows down and the community becomes fairly stable Climax community –stable mature community that undergoes little or no change

3-2: Biomes large group of ecosystems that share similar climates and organisms terrestrial or aquatic

Aquatic Biomes Marine biomes –4 marine groups Estuaries Intertidal zones Photic zones Aphotic zones Freshwater biomes

Estuaries occur where rivers join oceans and freshwater mixes with salt water salinity can change allowing a wide range of organisms to live here most are used as “nurseries” Organisms include: –snails, crabs, shrimp, clams, fishes, birds, grasses

Intertidal Zone portion of shoreline lying between high and low tide zones changing oxygen and nutrient levels crashing waves organisms include snails, sea stars, barnacles, clams, crabs

Photic Zone portion of marine biome shallow enough for sunlight to penetrate many diverse species plankton is abundant (small organisms that drift and float in photic zone) includes corals, fishes, sea plants, etc.

Aphotic Zone portion of marine biome where light does not penetrate organisms include crabs, squids, octopi, fishes, etc.

Freshwater Biomes ponds, lakes, rivers, streams includes organisms that not only live in the water but those that go on land as well organisms include frogs, snails, fish, turtles, plants, etc.

Terrestrial Biomes Think about traveling from north pole to equator—what changes would you observe? Why?

Latitude describes north-south position from equator Latitude and climate are directly related Latitude affects climate (temperature, precipitation, etc.) Small differences in temp. and precip. can create different biomes

Tundra treeless land with long summer days and short period of winter sunlight temperatures barely rise above freezing permafrost—permanently frozen layer of ground soil contains little nutrients little to no precipitation

Taiga also called boreal forest made mostly of coniferous trees—fir, spruce, hemlock—with poor acidic topsoil weather is harsh, but milder than tundra cold winters, little precipitation more organisms than tundra

Desert arid region with little to almost no plant life driest biome; less than 23 cm precip/year temperatures can be extremely high or extremely cold vegetation varies depending on rainfall

Grassland large communities covered with rich soil and grasses have more rain than deserts, but not enough to support tree growth increased diversity also called prairies, steppes, and pampas

Savannas are like grasslands, but receive enough rain to support trees American Buffalo

Temperate Forest deciduous forests with broad-leaved hardwood trees; cm of precip/yr in temperate zone— goes through seasons

Rain Forests forests receiving extensive amounts of rainfall; at least 200 cm/yr can be temperate or tropical Tropical –warm weather, wet weather, lush plant growth –near equator –greatest biodiversity –poor soil; nutrients recycled quickly