Ecology Biology I – Chapters 13-16

Chapter 13 What is Ecology? The study of the relationship among organisms and their environment. Abiotic vs Biotic factors Biotic: Living (animals and plants) Abiotic: Non-Living (climate, rocks, sunlight…)

Levels of Organization Biome – the organisms, climate, and plant communities Ecosystem – includes all biotic and abiotic factors Community – includes all the biotic facts that interact Population – all individuals of single species The single organism Levels of Organization

Changing 1 factor in an ecosystem can affect many other factors…. Biodiversity: The variety of living things in an environment. Many times it is dependent on the amount of natural resources (food/water/shelter) available. Question: Can you think of an area that would have the greatest biodiversity?

Keystone Species: An organism that has an unusually large effect on its ecosystem. Example: Beavers build dams and change flowing streams into ponds and wetlands. This effects fish, fish-eating birds, insects, water birds, and the animals that feed on the eggs of these birds. Take away the beavers and all the other animals are affected.

List at least 5 different organisms that were affected by returning the wolves. How did the wolves change the rivers?

Life in an ecosystem requires a source of energy Producers: Also called autotrophs. Produce there own food from non-living resources. Almost all get their energy from the sun. Consumers: Also called heterotrophs. Get their energy from eating other organisms.

Food chains and food webs model the flow of energy in an ecosystem. Herbivores: eat only plants Carnivores: eat only other animals Omnivores: eat both plants and animals Detritivores: eat only dead matter Decomposers: break down organic matter into smallest compounds (fungus and microorganisms)

Pyramid models the distribution of energy and matter in an ecosystem. Biomass (amount of dry mass of organisms in a given area) goes down the higher in the pyramid The amount of energy in the system goes down the higher in the pyramid. The number of consumers goes down higher in the pyramid.

Chapter 14 Interactions in Ecology Individual organisms and populations interact with each other and with their environment.

Habitat and Niche Every organism has a habitat and a niche Habitat: All the biotic and abiotic factors where an organism lives (Where the organism lives.) Ecological niche: All the physical, chemical and biological factors a species needs to survive. (How the organism lives within its habitat.) Includes: Food: Type of food, how it competes, where it fits into food web Abiotic factors: Conditions, such as temperature and water. Behavior: Time of day organism is active and when it reproduces.

Resources availability gives structure to a community. Competitive exclusion: When two species competing for the same resources, one will “win” being better suited to the niche. The other will be pushed out or go extinct. Niche partitioning: Niche is shared but different areas (i.e.. Animals feeding at top of tree and other at bottom of tree.) Evolutionary response: Species will develop to help take advantage of certain conditions. (Large teeth for large nuts/small teeth for seeds.)

Ecological Equivalents If similar species live in DIFFERENT ecosystems but have similar niches and habitats, they are called ecological equivalents. They do not compete for the same resources because they live in different places.

Community Interactions: Organisms interact as individuals AND as populations. Competition: Where organisms fight for the same limited resources. Predation: One organism captures and feeds on another organism Symbiosis: Close ecological relationship where two or more species live in direct contact.

Three different types of symbiosis Mutualism: Where both organisms benefit from each other (bees and flowers; bees get fed; flowers get their pollen spread) Commensalism: Where only one species benefits and the other is not harmed. (eye-lash mites) Parasitism: Where one species benefits and the other is harmed (fleas and ticks on dogs)

Population Density and Distribution Population Density: The number of individuals that live in an area # of individuals = population density Area Distribution: How the individuals are spread out Clumped Dispersion (fish schooling together) Uniform Dispersion (nesting sites for birds) Random Dispersion (sloth in rain forest)

Population Growth Patterns – Populations grow in predictable patterns. Immigration: Movement into a population from another populations Births: Increase the population Emigration: Movement out of a population Deaths: Decrease the population

Ecological factors that limit population growth. Carrying Capacity: The maximum number of individuals an environment can support. Population Crash: A dramatic decline in the a population over a short amount of time. Limiting Factor: The factor that has the greatest effect in keeping down the size of a population. (competition; predation; climate; natural disasters)

Ecological Succession: A process of change in the species that make up a community. Succession: Sequence of biotic changes that regenerate a damaged community. (i.e.. forest fire) Primary succession: pioneer species move in (lichens, mosses, grasses) and break down rock into soils. Over time, shrubs and tree begin to grow and their roots continue to break up ground and provide habitats for animals.

Ecological Succession: (cont…) Primary succession: (cont….) Different and larger trees begin to grow and provide more habitats for animals. Secondary succession: Re-establishment of area after damage has occurred. Soil already there, so process does not take as long.

Chapter 15 The Biosphere Climate and the distribution of land and water play a role in shaping ecosystems and influencing the distribution of organisms on Earth.

Life in the Earth System There are FOUR interconnected systems on Earth Biosphere: Where life exists Hydrosphere: All of the water, ice and water vapor Atmosphere: The air around the Earth Geosphere: Everything that makes up the inside of the Earth and it’s surface

Biotic and abiotic factors interact in the biosphere. Climate: Prevailing weather of a region Influence by amount and angle of sunlight. Tropical: near equator Temperate: between the equator and the poles Polar: near the north and south poles

Biotic and abiotic factors interact in the biosphere. Air and water movement: convection of air and water Landmasses: windward vs leeward; distance from sources of water Animals have to adapt to these abiotic factors or go extinct.

BIOMES: Land-based, global communities of organisms 6 Major Biomes: Tropical Grassland Desert Temperate Taiga Tundra

Other Ecosystems: Marine ecosystems: Global Estuaries and Freshwater ecosystems: Where water flows from the land into the ocean AND water systems on land.

Chapter 16 Human impacts on ecosystems

Human population growth threatens environmental quality and biodiversity, so conservation methods are necessary to protect Earth’s natural resouces. Notice these key words: growth, threatens, quality, biodiversity, protect

Human populations continue to grow. – WHY? Exerts pressure on Earth’s natural resources. – HOW? Management of resources will help to meet future needs. Air Quality: pollution and smog Water Quality: toxins in the food chain

Threats to Biodiversity Loss of Habitat Introduction of new species: Invasive Species Conservations is the key.