Name: _______________________________ECOLOGY

3-1 What is Ecology?• Ecology is the scientific study of

interactions among organisms and between organisms and their environment, or surroundings.– Many levels– Biosphere is alll of life

• The study of ecology ranges from the study of an individual organism to populations, communities, ecosystems, biomes—and, finally, to the entire biosphere.

• Some ecologists study interactions between a particular kind of organism and its surroundings. Such studies focus on the species level. A species is a group of organisms so similar to one another that they can breed and produce fertile offspring. Other ecologists study populations, or groups of individuals that belong to the same species and live in the same area. Still other ecologists study communities, or assemblages of different populations that live together in a defined area.

• Ecologists may study a particular ecosystem. An ecosystem is a collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment. Larger systems called biomes are also studied by teams of ecologists. A biome is a group of ecosystems that have the same climate and similar dominant communities. The highest level of organization that ecologists study is the entire biosphere itself.

ECOLOGY Practice Set #1

3-2 Energy Flow• Sunlight is the main energy source for life on Earth.

– Autotrophs directly use sun’s energy (Photosynthesis) to make energy supply• Aka Producers

– Heterotrophs consume other organisms for energy supply• Aka Consumers• Heterotroph types– Herbivores• Primary (1) Consumers

– Carnivores• Secondary (2) Consumers

– Omnivores– Detritivores• Decomposers

• The energy stored by producers can be passed through an ecosystem along a food chain, a series of steps in which organisms transfer energy by eating and being eaten.

• A food web links all the food chains in an ecosystem together.

• Each step in a food chain or food web is called a trophic level. Producers make up the first trophic level. Consumers make up the second, third, or higher trophic levels. Each consumer depends on the trophic level below it for energy.

ECOLOGY Practice Set #2

• An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web.– Can look at

• Energy• Biomass• Numbers

• The 10% Rule– When you go up a trophic level, only 10% of the previous level’s

______ is available.• Could be energy, mass, or numbers

3-3 Cycles of Matter• Unlike the one-way flow of energy, matter is recycled within and

between ecosystems. Elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another through biogeochemical cycles.– C, H2O, N are key ones

• Summary of the Water Cycle

• Summary of the Carbon Cycle

• Summary of the Nitrogen Cycle

ECOLOGY Practice Set #3

• When an ecosystem is limited by a single nutrient that is scarce or cycles very slowly, this substance is called a limiting nutrient.– Nitrogen and Phosphorus major ones– Too much nutrients? Algal bloom

4-1 The Role of Climate• Carbon dioxide, methane, water vapor, and a few other atmospheric

gases trap heat energy and maintain Earth's temperature range

4-2 What Shapes an Ecosystem?• The biological influences on organisms within an ecosystem are called

biotic factors. These include the entire living cast of characters with which an organism might interact, including birds, trees, mushrooms, and bacteria—in other words, the ecological community.

• Physical, or nonliving, factors that shape ecosystems are called abiotic factors . For example, the climate of an area includes abiotic factors such as temperature, precipitation, and humidity.

• Community interactions, such as competition, predation, and various forms of symbiosis, can powerfully affect an ecosystem.

ECOLOGY Practice Set #4

5-2 Limits to Growth• In the context of populations, a limiting factor is a factor that causes

population growth to decrease.• Predation Populations in nature are often controlled by predation. The

regulation of a population by predation takes place within a predator-prey relationship, one of the best-known mechanisms of population control. The relationships between sea otters and sea urchins and between sea otters and killer whales are examples of predator-prey interactions that affect population growth.

ECOLOGY Practice Set #5

5-3 Human Population• Exponential Growth

6-1 A Changing Landscape• Among human activities that affect the biosphere are hunting and

gathering, agriculture, industry, and urban development.

6-2 Renewable and Nonrenwable Resources• Renewable resources can regenerate if they are alive, or can be

replenished by biochemical cycles if they are nonliving. – Water, wind, sun

• A nonrenewable resource is one that cannot be replenished by natural processes.– Fossil fuels (reasonable rate)– Uranium Ore

• Human activities can affect the quality and supply of renewable resources such as land, forests, fisheries, air, and fresh water.

6-3 Biodiversity• Biological diversity, or biodiversity, is the sum total of the genetically

based variety of all organisms in the biosphere.

– 3 Levels• Ecosystem diversity• Species diversity• Genetic diversity

• Human activity can reduce biodiversity by altering habitats, hunting species to extinction, introducing toxic compounds into food webs, and introducing foreign species to new environments.

• Habitat destruction decreases numbers– Threatened < Endangered < Extinct

• Pollution accumulates in food chains– In this process, called biological

magnification, concentrations of a harmful substance increase in organisms at higher trophic levels in a food chain or food web.

• DDT was a pesticide– Fat soluble

• Invasive species increase their populations because their new habitat lacks the parasites and predators that control their population “back home.”

ECOLOGY Practice Set #6

6–4   Charting a Course for the Future • The Ozone layer is part of our atmosphere that contains ozone (O3). It

blocks UV radiation– Ozone layer damaged due to use of CFCs (coolants/propellants)

• The overall trend of the warming of the planet solely due to anthropogenic causes is called Global Warming.– Man causes: CO2 from combustion

• Higher amounts of GHGs– Effects

• Ocean rising• Decrease in biodiversity