Ecology

• Ecology is the study of the interactions of living organisms with one another and with their physical environment (soil, water, climate…)

• ECO =• LOGY =

What is ecology?

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the study of

LEVELS OF ORGANIZATION

Species

Population

Community

Ecosystem

Biome

Biosphere

Biosphere

• The biosphere contains the combined portions of the planet in which all of life exists, including land, water and atmosphere.

ENERGY FLOW• Every organism needs…

…ENERGY!!!

ENERGY FLOW• What are autotrophs?

• Organisms that capture energy from the sun or chemicals to produce their own food.

ENERGY FLOW• What is a producer?• Organisms that first

capture energy (Autotrophs)

• FIRST TROPHIC LEVEL

ENERGY FLOW• During photosynthesis,

autotrophs use light energy to power chemical reactions that convert CO2 and water into oxygen and high energy sugars (glucose).

PRODUCERSLAND:

PlantsUPPER LAYERS OF OCEAN:

AlgaeTIDAL FLATS/SALT MARSHES:

Photosynthetic bacteria / cyanobacteria

CHEMOSYNTHESIS

• Chemosynthesis is the process by which organisms use CHEMICAL energy to PRODUCE carbohydrates.

• Making food without sunlight!–Example: Bacteria

ENERGY FLOW• If AUTOTROPHS are called

PRODUCERS, because they make their own food, what are HETEROTROPHS called?

CONSUMERS• Organisms that consume plants or

other organisms to obtain energy.• All organisms that are NOT

producers!!! (Heterotrophs)• Three categories

–Primary–Secondary–Tertiary

PRIMARY CONSUMERS• Herbivores

–Eat plants or other primary producers• Examples

– Cows– Horses– Rabbits– Some Insects

• SECOND TROPHIC LEVEL

SECONDARY CONSUMERS• Carnivores

–Animals that eat animals–Examples: tigers, wolves, snakes

• Omnivores–Animals that are herbivores and

carnivores–Examples: bears, humans

• THIRD TROPHIC LEVEL

TERTIARY CONSUMERS

• Carnivores that consume other carnivores

• Known as “top carnivores”• Example:

–A hawk that eats a snake–A lion that eats a hyena

• FOURTH TROPHIC LEVEL

DETRITOVORES• Decomposes organic

material and returns the nutrients to the soil, water and air (making it available for other organisms).

• Examples: mites, earthworms, snails, crabs

DECOMPOSERS• Break down and absorb nutrients

from dead organisms• They cause decay• Decomposition of bodies and

wastes releases nutrients back into the environment to be recycled by other organisms.

• Examples: bacteria, fungi

SCAVENGERS• Do not kill their food—they

search for a source of food that is already dead

• “Clean-up” the ecosystem• Examples: buzzards

FEEDING RELATIONSHIPS

• Energy flows through an ecosystem in ONE direction:

Sun (or inorganic chemicals)

Autotrophs/Producers

Heterotrophs/Consumers

FOOD CHAIN• A food chain is a series of

steps in which organisms transfer energy by eating or being eaten.

• It is how energy moves through an ecosystem!

FOOD WEB• A food web is a network of

complex interactions formed by the feeding relationships among the various organisms in an ecosystem.

FOOD CHAIN vs. FOOD WEB

•A food web will link together all of the food chains in a particular ecosystem…

A terrestrial

food chain

A marine food chain

TROPHIC LEVELS• A trophic level is a step in a food

chain or food web.• Different organisms are on

different levels depending on their source of energy.

• Where does energy come from?SUN

TROPHIC LEVELS1st TROPHIC LEVEL Producers

2nd TROPHIC LEVEL Primary Consumers

3rd TROPHIC LEVEL Secondary Consumers

4th TROPHIC LEVEL Tertiary Consumers

TROPHIC LEVELS

• A consumer in a food chain depends on the trophic level below it for energy.

ECOLOGICAL PYRAMIDS

• An ecological pyramid is a diagram that show the relative amounts of energy or matter contained within each trophic level of a food chain or food web.

ECOLOGICAL PYRAMIDS

• Only part of the energy stored in a trophic level is passed on to the next because organisms use much of the energy they con

ENERGY PYRAMID• All energy originates from the

sun (or inorganic chemicals).• Sunlight (radiant energy) is

converted to digestible energy by plants during photosynthesis.

• When the plants are eaten, the energy is transferred to animals to sustain life.

• Energy is transferred up the food chain.

ENERGY PYRAMID

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THE RULE OF TENS• Only 10% of the energy in a

trophic level is passed on to the next level…90% of the energy is lost—where does it go?

• Given off as HEAT!!

BIOMASS PYRAMID• Biomass is the total amount

of living tissue within a trophic level.

• Represents the amount of potential food available at each trophic level.

PYRAMID OF NUMBERS

• Shows relative number of individual organisms at each trophic level.

LIMITATIONS OF TROPHIC LEVELS

Why can there not be too many links to one

food chain?

• Each trophic level can support about one-tenth the amount of living tissue as the level below it, because only 10% of the energy is passed up!!!

A few more things…

HABITAT

•The area where an organism lives

• Includes both biotic and abiotic factors

Biotic vs. Abiotic

Biotic• Bio- means: life• Tic- means: pertaining to

Biotic factors are the living organisms in a habitat!

Abiotic• Bio- means: life• Tic- means:

pertaining to• A- means: no, not

Abiotic factors are all the physical aspect of a habitat!

Examples: soil, water, weather

Abiotic Factors

•Water•Air

•Soil•Heat•Light