Ecology

To be used with Ecology Guided Notes

Gaccione/Bakka—Belleville High School

Ecology: the study of how living things interact with their physical environment

Ecological Organization

Organism

• A living thing

• Anything that possesses all of the characteristics of life

Ecological Organization

• Species: a group of organisms that can

mate & produce a fertile offspring

Ecological Organization

• Population: all the members of the same species that live in certain place at a certain time.

Ecological Organization

• Community: a collection of interacting

populations in an area

Ecological Organization

• Ecosystem: includes all of the organisms & the non-living environment.

– community members

in the ecosystem

must interact to

maintain a balance.

Ecological Organization• Biosphere: the portion of the earth where all life exists.

A 13 mile band that surrounds the earth. 6-7 miles into the atmosphere & 6-7 miles deep into the ocean.– Composed of many complex ecosystems.

Put in order:(small to large)communitypopulationbiosphereorganismecosystem

Ecosystems

An ecosystem is self-sustaining if:1. A constant source of energy

is supplied.

2. Living things use this energy and convert into organic molecules

3. A cycling of materials between organisms and their environment

Resources

• Organisms with similar needs may compete with each other for resources like:– Food– Space– Water– Air– Shelter

Limiting Factors

• Limiting Factor: anything that makes it more difficult for a species to live, grow, or reproduce in its environment

– Determines the types of organisms that exist in that environment

Acclimation when organisms acclimate to changes

• Range of Tolerance: the ability of an organism to withstand changes in their environment.

Abiotic Factors• Abiotic factors: nonliving factors which affect the

ability of organisms to survive and reproduce

Examples:

1. intensity of light2. range of temperatures3. amount of moisture4. soil or rock type5. availability of inorganic substances6. supply of gases such as oxygen, carbon

dioxide, and nitrogen7. pH

Examples of Abiotic Factors

What abiotic factors limit vegetation at higher altitudes?

lack of soil a low annual temperature strong winds steepness of the grade

Examples of Abiotic FactorsWhat abiotic factors allow rainbow trout to love

mountain streams?

the amount of dissolved oxygen due to current water temperature no pollution pH of 7 shelter river bottom for reproduction

Examples of Abiotic FactorsWhat abiotic factors limit the organisms that can

live there?

temperature sunlight lack of water winds shelter/shade

Biotic Factors

• Biotic factors: living factors which affect the ability of organisms to survive and reproduce

– Examples:• other organisms, such as a predator, food source

Can an abiotic factor such as RAIN affect many biotic factors?

Rain - ________ - ________ - _________grass mole eagle

Nutritional Relationships• Two types : Autotrophs & Heterotrophs

– Autotrophs: organisms that synthesize their own food from inorganic molecules

Plants that contain photosynthetic pigments, such as chlorophyll.

Nutritional Relationships• Two types : Autotrophs & Heterotroph

– Heterotrophs: can NOT synthesize their own food and are dependent on other organisms for their food

Types of Heterotrophs

• Saprophytes: include those heterotrophic plants, fungi, and bacteria which live on dead matter  (a.k.a. decomposers or detritivores)

Types of Heterotrophs

• Herbivores: plant-eating animals

Types of Heterotrophs

Omnivores:

• consume both

plants and meat

Types of Heterotrophs

• Carnivores: meat-eating animals

Types of Carnivores

Predators: animals which kill and

consume their other animals (prey)

Prey: animals which are killed by predators

More Predator/Prey Relationships

Types of Carnivores

Scavengers: those animals that feed on other animals that they have not killed

Examples: crows vultures hyenas

Which is the Predator?

Symbiotic Relationships

• Symbiosis: living together with another organism in close association

–Types of symbiosis:• Commensalism• Mutualism• Parasitism

Types of Symbiosis• Commensalism: one organism is

benefited and the other is unharmed (+,0)

– Example: barnacles on whales, orchids on tropical trees

Types of Symbiosis

• Mutualism: both organisms benefit from the association (+,+)

– Example: Nile crocodile opening its mouth to

permit the Egyptian plover to feed on

any leeches attached to its gums.

Types of Symbiosis• Parasitism: one organism benefits at the

expense of the host (+,-)

– Example: tapeworm and heartworm in dogs athlete's foot fungus on

humans

leech sucking blood from host

Symbiosis

Mutualism Parasitism

Commensalism

Energy Flow in an Ecosystem

• Food chain: a single pathway of feeding relationships among organisms that involves the transfer of energy.

Food Webs

• Food web: Interrelated food chains in a community– Most organisms may be

consumed by more

than one species

Trophic Levels

An organism’s position in a sequence of energy transfers

First trophic level

Second trophic

Third trophic

Fourth trophic

Energy Transfer

• There is a decrease in the overall energy as you move up in trophic levels.

• There is much more energy in the producer level in a food web than at the consumer levels

• Approximately 10% of ingested nutrients is passed on to the next trophic level to build new tissue

Energy Flow, continuedWhy is the % of energy passed on to the next trophic

level so low? • No transfer of energy 100%, therefore some energy is

lost in the form of heat

• Some animals escape from being eaten & just die. Their energy in their bodies do not pass to a higher energy level.

• Some animal parts can not be eaten.Cougar eats deer, can not extract energy from antlers, hooves or hair.

Biomass: amount of organic matter

producers primary consumers  

secondary consumers tertiary consumers

Terrestrial Energy Pyramid

Complete the Energy Pyramid using these organisms:

Eagles, Green Plants, Mice, and Snakes

Green Plants

Mice

Snakes

Eagles

Succession

• Succession: a gradual process of change and replacement of populations in a community.

– Succession occurs when the environment is altered.

– These changes cause species to replace others, resulting in long-term gradual changes in ecosystems

– Ecosystems tend to change until a climax community is formed.

Primary Succession

• The development of plant communities in an area that has never supported life.

• examples: bare rock, lava flow or glaciers.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Primary Succession - in a Pond

The Start of Primary Succession

• Pioneer organisms: the first organisms to inhabit a given location (example: lichens on bare rock)

– Breaks down rock into soil

– Establish conditions under which more advanced organisms can live.

Primary Succession ExampleAdirondack Bog Succession

1. water plants at pond edge

2. sedges and sediments begin to fill pond

3. sphagnum moss and bog shrubs fill pond  (cranberries)

4. black spruce and larch

5. birches, maple, or fir

Secondary Succession• is the change of species that follows disruption

of an existing community

• created by natural disasters or human activity

• Occurs in areas that previously contained life and SOIL!!!

• forest fire at Yellowstone National Park.

Secondary Succession Example

• If the BHS football field is not mowed, would it be primary or secondary succession?

Primary or Secondary Succession?Primary on rock Secondary on soil.

Climax Community• Climax community: a community that has

reach a stable state.

– populations remain stable and

exist in balance with each other

and their environment

– ecosystems may reach a

point of stability that can last for

hundreds or thousands of years

Climax Community• A climax community persists until a

catastrophic change alters or destroys a major biotic or abiotic resource – (ex. forest fires, abandoned farmlands, floods, areas

where the topsoil has been removed)

• After the original climax community has been destroyed, the damaged ecosystem is likely to recover in stages that eventually result in a stable system similar to the original one.

Biomes

• Biome: a large region characterized by a specific type of climate & certain plant and animal communities.

• A certain biome may exist in more than one location on earth.

• Biomes are terrestrial (dry) or aquatic (wet)– Dependent on:

• Temperature• Solar radiation• Precipitation

Terrestrial Biomes

• Terrestrial Biomes:– In general, six land biomes

– Characterized by climax vegetation

– Have characteristic flora (plants) and fauna (animals)

Terrestrial Biomes: Tundra• Climax flora: treeless. lichens,

mosses, grasses

• Climax fauna: caribou, snowy owl

• Characteristics: long & extremely cold winters& permanently frozen subsoil called permafrost

• Location:Continuous belt around N America, Europe & Asia

Terrestrial Biomes: Taiga

• Climax flora: conifersor evergreen trees

• Climax fauna: moose, black bear, squirrels

• Characteristics:long, severe winters

• Location:south of the tundra & north of temperate forest

Terrestrial Biomes: Temperate-Deciduous Forest

• Climax flora: trees that shed leaves

• Climax fauna: gray squirrel, fox, deer

• Characteristics: moderate precipitation, cold winters, warm summers

• Location:South of taiga

Terrestrial Biomes: Tropical Forest• Climax flora: many species

of broad-leaved plants

• Climax fauna: snake, monkey, and leopard

• Characteristics: heavy rainfall(300 inches/year), constant warmth

• Biodiversity:The size of 2 football fields may have 300 species of trees

• Location:Near the equator

Terrestrial Biomes: Grasslands• Climax flora: grasses

• Climax fauna: prairie dog, bison, usually herd animals.

• Characteristics: rainfall and temperature vary greatly, strong winds

• Grasslands: also known as prairies, steppes, savannas & pampas.

• Location: interior of continents

Terrestrial Biomes: Desert• Climax flora: drought-

resistant shrubs and plants

• Climax fauna: kangaroo rat, lizard

• Characteristics: sparse rainfall (9 inches/year).

• Extreme temperature. Hot days cool nights.Temperatures may have a 50 degree drop.

Aquatic Biomes

• Aquatic Biomes: the largest ecosystems on Earth– 70% of Earth’s surface is covered by water

– Water is the principal medium for life

– More stable then terrestrial biomes• Moisture not a limiting factor• Temperature changes are not as great

2 Types of Aquatic Biomes

• Marine Biomes: salt water biomes– Most stable aquatic environment– Habitat for large number of diverse organisms

• Freshwater Biomes: ponds, lakes, rivers & wetlands– Will fill in due to seasonal die-back and

erosion– Eventually terminate in a terrestrial climax

community

Freshwater Biomes

• 2 Types of Lakes:1. Eutrophic -rich in organic matter & vegetation

Murky waterBacteria feed on decomposing matter &

uses up all the oxygen, killing all life.

2. Oligotrophic -little organic matter & vegetationClear water.

Freshwater Biomes

• Wetlands: aka swamps & marshesan area of land that is covered by water for a

certain amount of time during the year.

Why are wetlands so important?filters out pollutantscontrols floodingstopover for migratory birdsrecreational

Zone of Photosynthesis• Plant production occurs at the edges of land

masses• No light penetrates the deeper regions of aquatic

biomes

Aphotic

Competition

• Competition: occurs when two different species or organisms living in the same environment (habitat) utilize the same limited resources– Examples:

• food, water, space, light, oxygen, and minerals.

• The more similar the requirements of the organisms involved, the more intense the competition.

Organisms in Ecosystem

• Habitat:– A place where an organism lives out its life. It

is an organism’s home, their address.

• Niche:

- The organism's role in the community. How

an organism meets its need for food, shelter,

how it survives & reproduces. Interactions

with biotic & abiotic factors.

Material Cycles• Material Cycles:

– In a self-sustaining ecosystem, materials must be recycled among the organisms and the abiotic environment.

– The same materials can be reused.

– Examples of Cycles:• Water• Carbon-Oxygen• Nitrogen

Water Cycle• Water Cycle: involves the processes of

–Photosynthesis–Transpiration–Evaporation and condensation–Respiration–Excretion

Water Cycle

Carbon-Oxygen Cycles

• Carbon-Oxygen Cycle:

involves the processes of

– Respiration– Photosynthesis

Carbon-Oxygen Cycle

oxygen

Nitrogen Cycle

• Nitrogen Cycle:– Organisms must have nitrogen to

produce proteins and amino acids

– Living things cannot use nitrogen gas in the air

– Life is possible due to nitrogen-fixation• Nitrogen Fixation: Nitrogen gas is

converted to ammonia

Nitrogen Fixers• Legumes: peas and beans contain

nitrogen-fixing bacteria in their roots– Clover and alfalfa are other examples of

nitrogen fixers

Bean Plant

Alfalfa

Nitrogen CycleNitrogen Gas (N2)

Nitrogen fixation

Nitrogen-fixingbacteria in plant roots

Animals eating plants

Decomposition

Soil bacteria

Biodiversity

• Evolutionary processes have resulted in a diversity of organisms and a diversity of roles in ecosystems.

• Biodiversity: the differences in living things in an ecosystem

1. Increased biodiversity increases the stability

of an ecosystem.

2. Increased biodiversity increases the chance that at least some living things will survive in the face of large changes in the environment

What are some other reasons biodiversity is valuable?

3. Biodiversity ensures the availability of a rich variety of genetic material that may lead to future agricultural or medical discoveries with significant value to humans. 

4. Biodiversity adds aesthetic qualities to the environment

Monoculture

• Monoculture: planting one species over a huge area – Why? – Leaves an area more vulnerable to predation

or disease

GLOBAL BIODIVERSITY VALUE

A map showingthe distributionof some of themost highly valuedterrestrial biodiversityworld-wide (mammals,reptiles, amphibians andseed plants), with red forhigh biodiversity andblue for low biodiversity

High Biodiversity vs. Low Biodiversity