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