Ecology: The study of living organisms and their environment

Who studies Ecology? Ecologists

Characteristics of Life

Made of one or more cells Organized

o Arranged in an orderly way with structures that have specific jobs

Grow and developo Increase in size and complexity over time

Reproduceo Produce offspring

Respond to Stimulio React to their environment

Require Energy Maintain Homeostasis

o Have an internal balance

Ecosystem Organization

Biotic Factors Abiotic Factors

Living parts of the environment

Nonliving parts of the environment

Animals Dirt

Plants Temperature

Levels of Organization

1. Population- 2 or more groups of organisms of the same speciesa. Ex: caribou

2. Community- 2 or more different populationsa. Ex: caribou, rabbits, owls

3. Ecosystem- Interaction between living and nonliving thingsa. Ex: bears, eagles, sun, water

4. Biomes- groups of ecosystems that have the same climatea. Ex: Evergreen Forest

5. Biosphere- total area that can support lifea. Sphere= circle Bio=life

Ecological Succession

Ecological Succession- change in an ecosystem when one community replaces another because of changing abiotic and biotic factors

Primary Succession- slow establishment of a community in a rocky area

Lichens break down rock and decompose to form soil (pioneer species)

Climax Community- A stable, mature community

Secondary Succession- return of native species to a habitat after a

disturbance

Biomes

Tundra- treeless biome with layer of permafrost below the surface

Short grasses, shrubs, caribou, polar bears, wolves, trout

Cold and dark much of the year

Boreal Forest (Taiga)- dense evergreen forest

Spruce and fir trees, deciduous trees, small shrubs, moose, beavers, deer

Short summers; long, cold winters

Temperate Forest- mainly deciduous trees, well-defined seasons

Oak, beech, maple trees, squirrels, rabbits, deer, foxes

Summers are hot, winters are cold

Grassland- fertile soils with lots of grasses

Droughts, grazing animals, grasses and herbs, horses

Summers are hot, winters cold, fires possible

Desert- more evaporation than precipitation

Cacti, succulents, lizards, bobcats, tortoises

Daily fluctuations in temperatures, low rainfall

Tropical Rain Forest- warm temperatures and lots of rain

Most biodiverse, tall trees, monkeys, tigers, toucans, sloths

Humid and rainy all year

Human Impacts on the Ecosystem

Negative impacts humans have on the Earth:

Habitat Loss- removal of the habitat

o Effect: no place for organisms to liveo Ex: Deforestation

Habitat Degradation- to make unlivableo Ex: Pollution

Acid Rain- rain that has a high concentration of acids because of air pollution

Ozone Depletion- less ozoneo Effect: more harmful UV rays reach Earth. Ozone depletion

can be caused by CFCs Greenhouse Effect- heat is trapped by gasses (like CO2) in the

atmosphere causing global warmingo This happens naturally

Factors that Increase Global Warming

Burn fossil fuels

Cut trees Drive cars

**If we keep adding carbon to the atmosphere the temperature will increase**

Factors that Decrease Global Warming

Plant trees Carpool Fuel efficient cars

Human Impact on Ecosystems (Continued)

Invasive Species- come from another area, they do not belong, have no predators, and reproduce and spread out of control

Pesticides- chemical substance that kills pests, can cause pesticide resistanceo DDT and Eagles

Pesticide Resistance-ability for insects to become resistant to a pesticide, causing humans to use something strongero Alternative to Pesticides

Biological Pest Control- use of living organisms or naturally produced chemicals to control pests

o Biomagnification- substances that do not break down naturally that can be passed up the food chain

Energy

All living things must have energy in order to maintain homeostasiso Homeostasis-an internal balance

# 1 energy source = SUN Autotroph- makes own food, gets energy from sun

o Photosynthesis- use sunlight Ex: Plants

o Chemosynthesis- use chemicals Ex: bacteria in the deep ocean autotrophs

Types of Heterotrophs

1. Herbivore: eats plantsa. Deer, Cows

2. Carnivore: eats meata. Lions

3. Omnivore: eats both plants and meata. Bears (eat berries and fish)

4. Scavengers: eat dead thingsa. Buzzards

5. Decomposers: biodegrade (break down) thingsa. Bacteria in a dumpster

Energy

Food Chain- The way energy is passed in an ecosystem, the feeding systemo Only 10% of energy goes to the next level. The rest is either

used or lost as heato As you move up the pyramid, energy is lost so the amount of

energy decreaseso Energy must be replaced by the suno Trophic Level= Energy Level

Ecological Pyramid- shows the amount of energy or matter contained within each trophic level

Pyramids show the transfer of:o Energy

o Biomass- amount of living matter at each trophic level

o Population Size- relative # of organisms at each trophic level

Energy (Cont.)

Only 10% of the available energy contained in one trophic level gets passed on to the next trophic levelo Ex: Algae (1000 cal- energy)minnow (100 cal) blue gill (10

cal) Where does the rest (90%) of that energy go?

o Lost as heato Not all of the food is eateno Not all of the food is digestedo Entire level cannot be consumed

Food Webs

Food Web- many interconnected food chainso The arrow in a food web ALWAYS points TOWARD the

CONSUMER in the direction of the flow of energy

Producer: - grass Primary Consumer-

grasshopper Secondary Consumer- Bird Tertiary Consumer- Hawk

Matter is Recycled

Water Cycle

Carbon Cycle

A. Plants take in CO2 (Photosynthesis)

B. We breathe in O2 from plants

C. We eat plants

D. We breathe out CO2 (Cellular Respiration)

Pollution Bad CO2 into air

Other Sources of Carbon:

Decomposition of dead organisms

Erosion and volcanoes

Burning Fossil Fuels

Cutting and burning trees

Carbon Cycle (Cont.)

Organisms/ Input Effects

CO2

A

O2

D

B

CFood

Plants (autotrophs) Photosynthesis (uses carbon)

Decomposers

Fungi/Bacteria

Carbon released when things die

Animals Cellular Respiration (release carbon)

Burning of Fossil fuels

(Dead organisms become coal, gas, oil)

Carbon Released

What would happen if decomposers were removed from the carbon cycle? The amount of carbon in the atmosphere would decrease

Nitrogen Cycle

Nitrogen gas in soil Enters in root nodules of plants like legumes Converted to ammonia by nitrogen-fixing bacteria Plant uses ammonia to build protein An animal converts plant protein to animal protein Animal carcass decomposed into nitrates (nitrification) Some nitrates broken down by soil bacteria (denitrification)

The Phosphorus Cycle

Short Term and Long-Term Cycles Short Term Cycle

o Phosphates in watero Producers take up phosphates from soilo Consumers eat phosphates in plantso Consumers die/ produce waste and decomposers break down

phosphorus Long Term Cycle

o Phosphorus used to make up rocks

What shapes an Ecosystem

Competition- fighting over resources

Habitat Niche

Where it lives What it does- its job

Ex: in a tree Ex: collect acorns

Niche includes

Type of food organism eats

Physical conditions needed to survive (ex. Place to hibernate)

How it reproduces (lays eggs in winter)

Competition is reduced by having organisms with different niches (needs)

Predator/Prey (Predation)

Predator: eats

Prey: gets eaten

It’s a cycle: prey up, predator up, then prey gets eaten, levels down,

predator down from lack of food, then back to beginning as prey

makes a comeback

Density Dependent Factor depends on the size of the population

Density Independent Factor does not depend on the size of the

population

Symbiosis living together, nothing dies

Mutualism- 2 species (both) benefit

Parasitism- 1 benefits, 1 harmed

Commensalism- 1 species benefits, 1

not benefited or harmed

Tropisms

Tropism- plants adjust growth in response to environmental stimuli

Gravitropism- (geotropism) a growth response to gravity

Phototropism- when stems/leaves adjust to the direction of growth in response to light

Thigmotropism- plants shift a direction of growth as they touch

Population Ecology

3 important factors affecting a population are:o Geographic distributiono Density- # of organisms/ areao Growth rate

Population growtho 3 factors that affect the population size

Number of births Number of deaths Number entering or leaving the population

Populations grow exponentially under the best conditions with unlimited resources results in a J-shaped curveo Growth initially starts slow, there are few reproductive

individualso Growth then begins to increase rapidly (ex. Increase due to

medical technology)o J-Curve- slow in beginning, then speeds up

Limits on the Environment

Populations are controlled by limiting factors Results in an S-Shaped Curve Carrying Capacity- maximum number of organisms an environment

can support indefinitelyo Above CC too many, some dieo Below CC room for more

Limiting Factor- anything that prevents some things from living in an areao Abiotic: temperature, rain, soilo Biotic: food, predators