Define ecology.

List the levels of ecological organization from largest to smallest.

Ecology is the scientific study of interactions among organisms & between organisms and their environment

Biosphere – all of the areas on earth where life exists◦ Includes land, water, & air◦ All living things in the

biosphere interact and depend on each other in order to sustain life

In order to fully understand how a biosphere works, ecologists study everything from a single organism to a whole biosphere◦ Species – a group of organisms who can breed &

produce fertile offspring◦ Populations – groups of individuals that belong to the

SAME SPECIES & live in the same area◦ Communities – many populations that live together in

the same area◦ Ecosystem – all of the organisms that live in a particular

place◦ Biome – a group of ecosystems that have the same and

similar communities

The highest level that ecologists can study is the biosphere

Define ecology.◦ Ecology is the scientific study of interactions among

organisms & between organisms and their environment

List the levels of ecological organization from largest to smallest.◦ Biosphere◦ Biome◦ Ecosystem◦ Community◦ Population◦ Species

Contrast biotic and abiotic factors.

Identify and explain the five types of community interactions.

Differentiate between primary and secondary succession

Biotic Factors – any living component of an ecosystem that can affect an organism◦ Example: A deer is

affected by the plants it eats, other animals that try to eat it, bacteria that can make it sick, etc.

Abiotic Factors – any nonliving component of an ecosystem that can affect an organism◦ Example: temperature,

climate, minerals, soil, etc.

Habitat – the area where an organism lives◦ Includes biotic & abiotic

factors

Niche – an organism’s role in an ecosystem◦ The types of food an

organism eats◦ How an organism gets its

food◦ What eats that organism◦ What temperature range an

organism can survive in◦ When & how an organism

reproduces

Organisms in the same community constantly interact

Community interactions help shape the ecosystem in which they live

Symbiosis – any relationship in which two species live closely together◦ Examples: mutualism, commensalism, parasitism

Types of Community Interactions◦ Competition◦ Predation◦ Mutualism◦ Commensalism◦ Parasitism

Competition –interaction where organisms try to use the same resource at the same time◦ Resource – any necessity

of life, including water, nutrients, light, food, or space

Competitive Exclusion Principle◦ No two species can

occupy the same niche in the same habitat at the same time

Predation –interaction where one organism captures & feeds on another ◦ Predator – the

organism who catches & eats another organism

◦ Prey – the organism that is captured & eaten

Mutualism – both species benefit from the relationship◦ Example: Flowers

depend on bees to pollinate them. The bees can then eat the nectar of the flower.

Commensalism – one member of a relationship benefits & the other is not helped or harmed◦ Example: Barnacles on

a whale’s skin do not help or harm the whale. However, as the whale swims, the movement of water past the barnacles carries food to the barnacles.

Parasitism – one organism lives in or on another organism & harms it

Parasites can weaken but usually do not kill their host.◦ Example: Ticks feed on

the blood of animals such as deer, dogs, and humans.

Ecosystems are constantly changing in response to natural and human disturbances

As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community

The series of predictable changes that occur in a community over time is called ecological succession

Primary succession is succession that occurs where no soil exists

Pioneer species are the first species to populate an area◦ Often is lichens

Secondary Succession is succession following a disturbance that destroys a community without destroying the soil

Tends to restore the ecosystem to its original condition

Can be caused by natural events (forest fire) or human disturbances (clear-cutting a forest)

Contrast biotic and abiotic factors.◦ Biotic Factors – any living component of an

ecosystem that can affect an organism

◦ Abiotic Factors – any nonliving component of an ecosystem that can affect an organism

Identify and explain the five types of community interactions.◦ Competition – interaction where organisms try to

use the same resource at the same time◦ Predation – interaction where one organism

captures & feeds on another ◦ Mutualism – both species benefit from the

relationship◦ Commensalism – one member of a relationship

benefits & the other is not helped or harmed◦ Parasitism – one organism lives in or on another

organism & harms it

Differentiate between primary and secondary succession◦ Primary succession is succession that occurs where

no soil exists

◦ Secondary Succession is succession following a disturbance that destroys a community without destroying the soil

Contrast producers, consumers, detritivores, and decomposers.

Describe a food chain

Describe a food web

Identify the three types of ecological pyramids

Ecosystems need a circular flow of energy in order to support and sustain life

ALL energy is originated from the sun

Producers are organisms that capture energy from the sun and convert it into food◦ This process is called

photosynthesis

Also known as autotrophs

Plants, some bacteria, and algae are producers

Consumers are organisms that obtain energy by eating other organisms

Also known as heterotrophs

All animals, most protists and bacteria, and all fungi are consumers

Herbivores –consumers that eat only plants◦ Examples: deer, cows,

caterpillars

Carnivores –consumers that eat only animals◦ Examples: wolves,

snakes, owls

Omnivores –consumers that eat both plants & animals◦ Examples: humans, bears,

crows

◦ Detritivores are organisms that feed on plant and animals remains, and other dead matter

Examples:◦ Earthworms

◦ Snails

◦ Mites

◦ Crabs

Decomposers are organisms that break down organic matter◦ Examples: fungi &

some types of bacteria

Decomposers return nutrients, minerals, & some organic matter back to the soil or the atmosphere to be used by plants and other producers

A food chain is a series of steps where organisms transfer energy by eating & by being eaten

Food chains move in a straight line

Food chains usually show no more than 5 organisms

Arrows show the direction of energy flow

ProducerPrimary

Consumer

Secondary

Consumer

Tertiary

Consumer

Quarternary

Consumer

Producer/Autotroph Herbivore Carnivore

Carnivore,

Detritivore, or

Decomposer

Carnivore,

Detritivore, or

Decomposer

Food chains do not show all of the feeding relationships in an ecosystem◦ Most organisms eat & can be

eaten by more than one organism

Food Web – a network of complex feeding interactions in an ecosystem◦ Food webs show all of the

feeding relationships in an ecosystem

Each step in a food chain or food web is called a trophiclevel

Ecological pyramidsshow the relative amounts of energy or matter in each trophic level

Types of Ecological Pyramids◦ Energy Pyramid

◦ Biomass Pyramid

◦ Pyramid of Numbers

Energy pyramids (also called trophicpyramids) show how much energy is available at each trophic level

Only 10% of energy is transferred to each trophic level

The remaining 90% of the energy is used by the organism to carry out life processes◦ Some is also released as heat

Producers (autotrophs) – 100% of the energy

Primary Consumers (herbivores) – 10% of the energy

Secondary Consumers (carnivores) – 1% of the energy

Tertiary Consumers (carnivores, detritivores, decomposers) – 0.1% of the energy

Biomass pyramids show the amount of potential food available for each trophic level◦ Biomass – the total amount of living tissue Grams of organic matter per unit area

◦ You usually have more plants than herbivores, more herbivores than carnivores, etc.

A pyramid of numbers shows how many individual organisms are in an ecosystem◦ Sometimes it will not look like a pyramid because,

for example, there are more individual insects than individual trees, but the trees have more energy and biomass.

Contrast producers, consumers, detritivores, and decomposers. ◦ Producers are organisms that capture energy

from the sun and convert it into food

◦ Consumers are organisms that obtain energy by eating other organisms

Detritivores are organisms that feed on plant and animals remains, and other dead matter

Decomposers are organisms that break down organic matter

Describe a food chain◦ A food chain is a series of steps where organisms

transfer energy by eating & by being eaten. Food chains move in a straight line and usually show no more than 5 organisms.

Describe a food web.◦ Food Web – a network of complex feeding

interactions in an ecosystem

◦ Food webs show all of the feeding relationships in an ecosystem

Identify the three types of ecological pyramids◦ Energy pyramid, biomass pyramid, pyramid of

numbers