Module B Review

2nd Quarterly Assessment ReviewUnit 8

BIO.B.4.1, BIO.B.4.2-Describe ecological levels of organization in the biosphere. - Describe the levels of ecological organization (i.e., organism, population, community, ecosystem, biome, and biosphere). - Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems. - Describe interactions and relationships in an ecosystem. - Describe how energy flows through an ecosystem (e.g., food chains, food webs, energy pyramids). - Describe biotic interactions in an ecosystem (e.g., competition, predation, symbiosis). - Describe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle). - Describe how ecosystems change in response to natural and human disturbances (e.g., climate changes, introduction of nonnative species, pollution, fires).

- Describe the effects of limiting factors on population dynamics and potential species extinction.

Biotic factors are living things, or things that were once living

• Examples: plants, animals, fungi, bacteria• Each organism plays a particular role in the

ecosystem.

Abiotic Factors are nonliving

• Examples: moisture, temperature, wind, sunlight, soil.

• The balance of these factors determines which living things can live in a particular environment.

13.3 Energy in Ecosystems

• Life in an ecosystem requires a source of energy• Producers provide energy for other organisms in an

ecosystem.– Producer: An organism that gets their energy from

non-living resources. Example: Plants• Also called autotrophs• Get energy from photosynthesis or

chemosynthesis– Chemosynthesis: process by which an

organism forms carbohydrates using chemicals as an energy source.

Energy In Ecosystems• Consumers are organisms that get their

energy by eating other living things– Also called heterotrophs– All consumers somehow depend on

producers for food.– Examples: wolf, human, rabbit

Food Chains & Food Webs• Food chain: a model that shows a sequence of feeding relationships.

– Shows the transfer of energy from oneorganism to another– Each level of nourishmentin a food chain is called a trophic level

• A food web is a model that shows the complex network of feeding relationships and the flow of energy within an ecosystem.

• A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem.

• Between each tier of an energy pyramid, up to 90 percent of the energy is lost into the atmosphere as heat.

• Only 10 percent of the energy at each tier is transferred from one trophic level to the next.

• A vast number of producers are required to support even a few top level consumers.

tertiaryconsumers

secondaryconsumers

primaryconsumers

producers

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Energy Pyramids

Elements essential for life also cycle through ecosystems-examples: oxygen, carbon

• A biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an ecosystem.

What’s the difference between a habitat and niche?

• Habitat: All of the biotic & abiotic factors in the area where an organism lives (i.e. grass, trees, watering hole)

• Niche: Includes the same as the habitat. (All of the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduce),but also includes the animals behaviors. (i.e. type of food species eats, temperature it can tolerate, time of day it is active, how it interacts with others)

• Habitat is where a species lives (“address”), niche is how it lives there (“job”)

Competition and predation are two important ways in which species interact.

1. Competition: Two organisms fight for the same limited resources.

– Intraspecific: members of the same species (Ex: territory fights)

– Interspecific: Two different speciesEx: Plants (fighting for the same space)

2. Predation: One organism captures and feeds upon another organism.

Symbiosis is a close ecological relationship between two or more organisms of different species that live in direct contact with one another.

• Mutualism: Both species benefit from one another. Example: bat & cactus

• Commensalism: One species benefits from the other, the other is neither helped nor harmed.

Example: Humans & demodicids• Parasitism: One organism benefits while the

other is harmed. Ex.: Tapeworms– Endoparasite: Live in the tissues and organs of the host– Ectoparasite: Lives on the exterior of the host

Types of Population Growth• Exponential Growth – occurs when individuals

reproduce at a constant rate under ideal conditions; population size increases dramatically over a period of time.– Examples: J-curve, human population

Fruit Fly Population Growth

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Types of Population Growth• Logistic Growth – population rises

exponentially and then growth slows when it reaches its carrying capacity.

• Carrying capacity: The maximum number of individuals of a particular species that the environment can normally and consistently support.

• S-shaped Curve

Rabbit Population Growth

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Density-dependent limiting factors

• Affected by the number of individuals in a given area

• Examples: Competition, predation, parasitism, disease

Density-Independent Limiting Factors

• Aspects of the environment that limit population growth regardless of population size.

• Examples: Unusual weather, natural disasters, human activities.

Primary Succession• The establishment and development of an

ecosystem in an area that was previously uninhabited.

• Can begin due to melting glaciers, volcanic eruptions, or landslides.

• First organisms to live in a previously uninhabited area are called pioneer species.– Examples: lichens and mosses that can break

rock down into smaller pieces.

Secondary Succession

• The reestablishment of a damaged ecosystem in an area where the soil was left intact.

• Plants and other organisms that remain start the process of regrowth.

• Small disturbances start the process again and again.– Example: forest fire, tree falling

The growing human population exerts pressure on Earth’s natural resources.

• Nonrenewable resources are used faster than they form.– Coal– Oil– Natural Gas• 77 million barrels per day are used (2006)• Our dependency on these resources is depleting them.

• Renewable resources cannot be used up or can replenish themselves over time.– wind– water– sunlight

Pollutants accumulate in the air.

• Pollution is any undesirable factor added to the air, water, or soil.

• Smog is one type of air pollution.– sunlight interacts with pollutants

in the air– pollutants produced by fossil

fuel emissions– made of particulates and

ground-level ozone– Smog can be harmful to human

health.

• Acid rain is caused by fossil fuel emissions.– produced when pollutants in the water cycle cause rain pH to drop– can lower the pH of a lake or stream– can harm trees

• Global warming refers to the trend of increasing global temperatures.

North Pole

Loss of habitat eliminates species.

• Habitat fragmentation prevents an organism from accessing its entire home range.– occurs when a barrier forms within the habitat– often caused by human development– Habitat corridors are a solution to the problem.– allow species to move between different areas

of habitat

Introduced species can disrupt stable relationships in an ecosystem.

• An introduced species is one that is brought to an ecosystem by humans.– accidental– purposeful

• Invasive speciescan have anenvironmentaland economicimpact.

• Invasive species often push out native species.

• There are several ways that people can help protect the environment.– control population growth– develop sustainable technology and practices– protect and maintain ecosystems