Unit 2: Ecology

I. What is the biosphere and how is it organized?A. Biosphere – Area of the earth where life exists; extends from oceans depths to a few kilometers above land. B. Biomes – An extensive areas of similar climate and vegetation; there are six terrestrial biomes and three aquatic biomes.

1. Terrestrial Biomesa. Tundra

i. Extremely cold temperatures, low precipitation and permafrost present.

ii. Plants are short due to permafrost; animals adapted to cold (ex. thick fur).

b. Taiga/Boreal Foresti. More

precipitation than tundra with long severe winters.

ii. Plants are coniferous, evergreen trees with needles; animals may migrate .

Unit 2: Ecology

c. Deciduous Foresti. Abundant precipitation with four distinct seasons. ii. Plants are deciduous (drop leaves annually); animals adapted to seasons (ex. squirrels store nuts in winter)

d. Grasslandsi. Experience a dry season that prevents forest

development. ii. Plants (grasses) form a dense mat called sod, and enrich soil when they decompose; animals may graze.

e. Deserti. Driest biomes and temperature varies drastically between day and night. ii. Plants are succulent (store water in tissues);

animals may be nocturnal.f. Tropical Rainforest

i. Most precipitation, warmest temperatures; forest is layered (canopy, understory, floor)ii. Plants have large leaves to collect sunlight; animals are diverse due to numerous niches.

Unit 2: Ecology2. Aquatic Biomes – based on salinity (amount of

salt)a. Marine

i. Highest salinity, divided into zones by depth and light.

ii. Plankton are floating organism such as some algae and shrimpb. Estuary

i. A type of wetland that occurs where freshwater meets saltwater.

ii. Includes a great diversity of organisms due to high nutrient content; many organisms use as a nursery area. c. Freshwater

i. Lowest salinity; includes lakes, ponds, rivers, streams, and inland wetlands.

ii. Plants may have adaptations for limited oxygen (ex. cypress knees); some fish can only be found in areas of high oxygen content (ex. trout in rapid

moving water)

Unit 2: EcologyReview Questions1. What are the two basic types of biomes?

Terrestrial (land) and aquatic (water) biomes

2. Why are plants and animals in one biome different from plants and animals in a different biome?Plants and animals are climate and vegetation of a particular biome.

3. What factor is used to classify aquatic biomes?The salinity (amount of salt) is used to classify aquatic biomes.

Unit 2: EcologyC. Ecosystem 1. A physically distinct, self supporting

unit of interacting organisms and their environment.

Ex. Forest or pond2. Four important processes:

a. Production of energy (usually from sunlight)

b. Energy transfer c. Decompositiond. Reuse of nutrients

3. Includes biotic and abiotic factors. a. Biotic – living things b. Abiotic – nonliving

thingsEx. Temperature, light, nutrients

Unit 2: EcologyD. Communities and Populations

1. Communities – all the ecosystem’s interacting biotic factors. 2. Communities may be broken down into smaller units called populations.

a. Populations – A group of individuals that belong to the same species and occupy the same area and share common resources.

i. Each population has a specific niche, which means total way of life.

ii. The niche includes habitat, place in food web, competition,interrelationships, and resource needs (temperature, water)

b. A community may have 1000’s of populations (tropical rainforest) or relatively few (tundra)

Unit 2: Ecology

Review Questions1. List the levels of organization of the biosphere from highest level

(biosphere) to the most specific level (niche).Biosphere, Biome, Ecosystem, Community, Population, niche

2. What is the difference between an ecosystem and a community?An ecosystem includes all of the abiotic (nonliving) and biotic (living) factors in the environment, but a community includes only the interacting biotic (living) factors of an ecosystem.

3. What four essential processes would be found in an ecosystem?a. Production of energyb. Energy Transferc. Decompositiond. Reuse of nutrients

Unit 2: EcologyII. How is energy transferred in an ecosystem?

A. Trophic Levels1. Organisms in a community survive by either producing or consuming food.2. Trophic levels – levels of feeding in a community

a. Producers – produce food for themselves (ex. plants). Other organisms may eat producers. b. Consumers – must take in food (ex. fungi)

i. Primary Consumers – also called herbivores (ex. cow)

ii. Secondary and Tertiary Consumers – may be carnivores (ex. lion) or omnivores (ex. bear)

iii. Decomposers – as they consume, they break down wastes and dead organisms and return nutrients to the soil.

Unit 2: EcologyB. Food Webs

1. Made up of overlapping food chains.2. Shows feeding connections; arrows illustrate energy transfer

3. Ex.

Unit 2: Ecology

C. Ecological Efficiency1. Producers have most available

energy (sun).2. Energy is lost as it moves up

through the food web.3. The “lost” energy is used to catch,

eat, and digest food.

Unit 2: Ecology

Food Web Practice Liza Lizard carefully moved through the gravel of the driveway

toward her favorite afternoon snack, a tasty shrub beneath the kitchen window. She noticed a brightly colored insect already settling down to nibble a few leaves of the shrub, and called out a greeting, “Hello Ingrid, how are you today?” Ingrid looked up and smiled, “The cacti at the end of the drive was occupied by a family of rats eating breakfast, so I thought I would start here, and then move there for lunch!” Liza nodded. The rats would most likely show up for a shrub dessert, so she had better get started – that meant Ingrid was safe from her (for now, anyway!). Suddenly, Ricky Roadrunner sprang from the corner, gobbling up poor Ingrid and eyeing Liza with predatory interest. Before Ricky could snap up Liza, both heard the howl of a coyote and Ricky ran toward the forest before he became brunch. Liza was suddenly staring, frightened, at Cora Coyote. Cora spoke, “Don’t worry, I don’t like lizard meat. Too bad about the insect and roadrunner, that would have been a good lunch. I’ll just wait for the rats.”

Unit 2: EcologyReview Questions1. What is a trophic level?

A level of feeding within a community.

2. What is the difference between an omnivore and a carnivore?An omnivore feeds on both producers (plants) and animals, a carnivore feeds only on other animals.

3. From the food web above, write out a food chain that includes the rat. seedsratowlGrasshopper ratfoxGrasshopperratowl

4. Which level in a food web has the most energy? EXPLAIN.The producers have the most energy. As energy moves up through a food web it is “lost” and used to by animals to catch prey, eat, and digest food.

Unit 2: Ecology

III. How is matter reused in an ecosystem?A. Role of Decomposers

1. Decomposers break down wastes and dead organisms

2. Decomposition allows nutrients to be returned to the soil and atmosphere; this allows nutrients to be reused.

3. Decomposers include fungi, bacteria, and invertebrates.

Unit 2: EcologyB. Biogeochemical Cycles – the pathway through which a substance is recycled.

1. Water Cyclea. Enters

ecosystem by

precipitation; may Infiltrate

the soil (be absorbed) or run-off

into surface water.

b. Returned to atmosphere by evaporation or

transpiration (the loss of

water by plants)

Unit 2: Ecology2. Carbon Cycle

a. Powered by two main processesi. Photosynthesis – plants

and algae capture CO2 from the air and change it into

sugar (which have carbon)ii. Respiration – all living

things break down sugars for energy, which returns CO2 to the

atmosphere b. Other factors in the carbon cycle:

i. Decomposition returns carbon to the soil and

atmosphere.ii. Humans burn fossil fuels

which adds CO2 to the atmosphere.

Unit 2: Ecology

3. Nitrogen Cyclea. Nitrogen is essential for living organisms so that they can build proteins; nitrogen is plentiful in the

atmosphere, but is not usable in this form.b. Nitrogen fixation – bacteria living in the root nodules of bean plants (legumes) convert nitrogen from the air

into a more usable form.c. Nitrogen fixation is the first of many steps that involves bacteria and changing the form of nitrogen.

Unit 2: Ecology

Review Questions1. Could nutrients be reused without decomposers?

EXPLAIN.No, decomposers breakdown wastes and return the

nutrients to the soil to be reused.

2. How do plants return water to the atmosphere?Transpiration, the loss of water through their leaves.

3. What two processes drive the carbon cycle? Photosynthesis and Respiration

4. What organisms are essential for the conversion of nitrogen? Bacteria

Unit 2: Ecology

IV. How do living things interact in a community?A. Competition – a struggle for resources among organisms.

Ex. nesting space for birdsB. Predation

1. Predators are organisms that consume other organisms.

Ex. Zebra eating grass2. Prey are the organisms that are

consumed. Ex. Earthworm being eaten by bird

Unit 2: Ecology

C. Symbiosis – two organisms of different species living together in a close, permanent relationship; 3 types1. Mutualism – the two organisms benefit each other

Ex. Termite and protozoanEx. Lichen – an alga and a fungus

2. Commensalism – one organism benefits and the other not benefited or harmed

Ex. Barnacles and whalesEx. Epiphytes (ie. Spanish moss) and

trees3. Parasitism – one organism benefits and the other is harmed

Ex. Tapeworm and humanEx. Mistletoe and tree

Unit 2: EcologyReview Questions1. Which biotic relationship is defined as a

“struggle for resources”?Competition

2. In your backyard, you observe a snake entering your bird feeder. Who is the predator and who is the prey?The snake is the predator, the bird is the prey.

3. Match the type of symbiosis with the symbols:

__B___(+, +) a. parasitism

__C___(+, 0) b. mutualism __A___(+, -) c.

commensalisms

Unit 2: Ecology

V. How do communities change over time?A. Population growth

Unit 2: Ecology

2. Limiting factors, such as availability of food, water, and space establish a carrying capacity for populations; this type of growth is known as an S-curve

3. Carrying capacity is defined as the number of individuals an environment can support

Unit 2: EcologyB. Ecological Succession

1. Succession is the idea that communities will replace other communities in a predictable, orderly way; this happens because every community alters the physical factors of the environment; may be terrestrial or aquaticEx. As trees grow, they produce shade2. This process takes a long time (100’s to 1000’s of years)

Unit 2: Ecology3. Process of successiona. Pioneer species are the first organisms to inhabit an area; must be able to survive harsh conditionsb. Intermediate communities – multiple communities that each change the environment and “pave the way” for other communitiesc. Climax community –the final stage in succession; it is the most stable community for that biome

4. Two types of successiona. Primary succession occurs in areas that have not supported communities before

i. May occur on bare rock, paved parking lots, sand dunes, or after a volcanic eruption

ii. Typical processLichen Moss Grasses Shrubs

Trees

Unit 2: Ecology

b. Secondary succession occurs in areas that have supported communities before

i. May occur on abandoned farm land, after forest fires, or after heavy water pollution

ii. Typical processGrasses Shrubs Pine trees

Hardwoods

5. Animal communities change in response to changes in the plant communities and availability of prey

Unit 2: EcologyReview Questions1. What kind of curve illustrates exponential growth?

J- Curve

2. What determines the carrying capacity of the environment? The amount of available resources in the ecosystem

3. List 3 examples of limiting factors.food, water, space

4.What is ecological succession?The way that a community replaces itself in an organized and predictable manner.

5. What is the difference between primary and secondary succession?Primary succession begins in an area that has never supported a community before, like a bare rock. Secondary succession would take place in an area where a community was supported but was destroyed by a natural disaster.

Unit 2: Ecology

VI. What technology helps scientists study the complex systems in ecology?A. Global Positioning System – satellite based navigation system that allows the exact determination of a location. This is used for GIS (geographic information systems), which can:

1. Store, manage, and integrate data relating to points (individual trees), lines (rivers, roads), and boundaries.

2. Search for areas with a particular factor (Ex. specie)

Geographical analysis (Ex. statistical analysis 3. between habitat and reproductive success)

4. Displaying data in maps

Unit 2: EcologyB. Biological Sampling – techniques that allow the scientist

to quantitatively evaluate an area in terms of its biotic factors1. Mark/Recapture Method – a method that allows scientists to estimate the population number in an area. This is important in areas where the population is simply too large to count individually.

a. The scientist captures a segment of the population and “marks” these individuals.

b.The scientist then releases the marked individuals back into the population.

c. The scientist uses the same technique to capture individuals of the same population. The number of d. “marked” individuals in the second sample is counted.

The scientist uses the recorded numbers to estimate the total population size by solving for “Total Number”:Total Number = # in Second Sample

# in First Sample # of Marked Recaptures

Unit 2: Ecology2. Quadrant Analysis – scientists use a “quadrant” to select an area of an ecosystem. The quadrant (basically, a large square) is a measured area that:

a. Reduces the space a scientist must analyze

b. Ensures the size of the area remains the same if the scientist chooses to analyze several areas, or the same area over a period of time.

C. Water/Soil Analysis – using chemical tests or sampling techniques to determine the chemical or physical characteristics of water or soil. (Ex. dissolved oxygen, pH, contamination, and microorganism presence in soil or water)

Unit 2: EcologyReview Questions1. What is GIS?

Geographical information systems that store, manage, and integrate data from a specific geographical point. The data can then be combined and displayed on a map.

2. Why would a scientist use the mark/recapture method instead of counting each member of the population individually?This method is useful when populations are too large to count individual members.

3. What is a quadrant?A selected large square area that scientists will analyze.

4. What types of things would be tested in a water analysis?dissolved oxygen, pH, presence of microorganisms,