Ecosystems

What is ecology?

Habitats

An organism obtains food, water, shelter , and other things it needs to live, grow, and reproduce from its environment.

Organism = an individual animal, plant, or single-celled life form (living thing)

Habitat = an environment that provides the things the organism needs to live, grow, and reproduce

Why do different organisms live in different habitats?

Biotic FactorsAn organism interacts with both the living and nonliving parts of its habitat.

Biotic Factors = the living parts of a habitat

Name a biotic factor in your environment.

Abiotic Factors Abiotic factors =

the nonliving parts of an organism’s habitat

Examples: water, sunlight oxygen, temperature, and soil

Levels of Organization

Population = all the members of one species in a particular area

Species = a group of organisms that are physically similar and can mate with each other and produce fertile offspring.

Levels of Organization Community = all the different populations that

live together in an area

Ecosystems = the community of organisms that live in a particular area, along with their nonliving surroundings

SummaryThe smallest level of organization is a single organism, which belongs to a population that includes other members of its species. The population belongs to a community of different species. The community and abiotic factors together form an ecosystem.

Energy RolesAn organism’s energy role is determined by how it obtains energy and how it interacts with other organisms. Each of the organisms in an ecosystem fills the energy role of producer, consumer, or decomposer.

Energy Roles Producers = organisms that make their own food Example: plants, algae and some bacteria Energy enters most ecosystems as sunlight Most producers use the sun’s energy to make

food molecules (photosynthesis)

Energy Roles Consumer = an organism that obtains

energy by feeding on other organisms

Herbivores = consumers that eat only plants

Carnivores = consumers that eat only animals

Omnivores = consumers that eat both plants and animals

Scavenger = a carnivore that feeds on the bodies of dead organisms

Let’s Discuss What do herbivores and carnivores have in

common?

What does an ecosystem need in order to allow matter to be recycled?

Energy Roles Decomposers break down wastes and dead

organisms and return the raw materials to the ecosystem.

Examples: mushrooms & bacteria

The movement of energy through an ecosystem

What is the difference between a food chain and a food web?

Example of Ecosystem

The movement of energy through an ecosystemA food chain is a

series of events in which one organism eats another and obtains energy.

The movement of energy through an ecosystemA food web

consists of the many overlapping food chains in an ecosystem.

Energy PyramidAn energy pyramid shows the amount of energy that moves from one feeding level to another in a food web

Draw the pyramid

Decomposers

Another Way To Look At

It

Biomass PyramidA biomass pyramid represents the total

mass of living organic matter (biomass) at each trophic level in an ecosystem.

Adapting to the environment Natural selection: A

characteristic that makes an individual better suited to its environment. Individuals differ, and

some of these differences can be passed down to offspring.

More offspring are produced than what can survive and reproduce.

There is a struggle for existence (competition).

Individuals best suited for their environment survive and reproduce. It is essentially the survival of the fittest.

This is the result of species adapting to their environment

Adapting to the environment

Adaptations- the behaviors and physical characteristics that allow organisms to live successfully in their environments.

Individuals with characteristics that are poorly suited to their environment are less likely to survive and reproduce.

Over time, poorly suited characteristics may disappear from a species.

Adapting to the environment

Niche- is the role of an organism in its habitat and how it makes it living.

Includes the type of food the organism eats, how it obtains the food, and which other organism use the organism as food.

Also includes when and how the organism reproduces and the physical conditions required for it to survive.

Competition What happens when two species occupy

the same niche? Different species can share the same habitat

and food requirements. If two species occupy the same niche (home)

one of the species will eventually die off. The reason for this is competition, the

struggle between organisms to survive as they attempt to use the same limited resource.

Predation

Predation An interaction in

which one organism kills another for food is called predation.

The organism that does the killing is the predator.

The organism that is killed is the prey.

Predator Adaptations Predators have adaptations

that help them catch and kill their prey. For example, a cheetah can run very fast in a short amount of time to catch its prey.

Some predators also have adaptations that help them hunt at night. For example, the big eyes of an owl let in as much light as possible to see in the dark.

Symbiosis Symbiosis is a close

relationship between two species that benefits at least one of the species.

There are three types of symbiotic relationships: mutualism, commensalism, and parasitism.

Mutualism A relationship in which both species

benefits one another is called mutualism.

In some cases, 2 species are so dependent on each other that neither could live without the other.

Commensalism Commensalism is a

relationship in which one species benefits and the other species is neither helped nor harmed.

This type of relationship is not that common in nature because two species are usually either helped or harmed a little by interaction.

Red-tailed hawks build their nests on top of saguaro cacti. The hawks benefit from having a home and the cactus are not affected.

Parasitism

Parasitism involves one organism living on or inside another organism causing it harm.

The organism that benefits is called the

parasite The organism it lives on is called the

host.

Studying populations Population density is the number of

individuals in an area specific to size. For example, suppose you counted 20 butterflies in a garden measuring 10 sq. meters. The population density would be 20 butterflies per 10 square meters.

Limiting Factors A limiting factor is an environmental

factor that cause a population to decrease.

Can you name some limiting factors in an ecosystem? Food? Water? Space? Weather conditions?

Carrying Capacity The largest population that an area can

handle is it carrying capacity. A population usually stays near its

carrying capacity because of its limiting factors in its environment.

Changes in Population Size

Changes in population can be displayed in a line graph. The graph shows the population changes in a rabbit and fox population over time.

1 2 3 4 5 6 7 8 9 100

100200300400500600700800900

Chart Title

Rabbits Foxes

Year of Study

Num

ber

of

Rabbits

and F

oxe

s

CYCLESMatter Cycles

http://www.songsforteaching.com/curriculumrocks/watercycle.htm

WATER CYCLE

NITROGEN CYCLE

Carbon-Oxygen Cycle

The Food Cycle