Unit 2Relationships in Ecosystems

WARM-UP Questions1. What do you think the basic

needs of life are?

2. What is the environment?

3. How do you define life…what are 4 things all living

organisms have in common?

What is Ecology?The science of ecology includes everything from global processes (above), the study of various marine and land habitats (middle)

to individual interspecific ( BETWEEN SPECIES) interactions like predation and

pollination (below).

Levels of Organization

studied in Ecology…

Ecology is…

• the study of the interactions between living organisms and

their biotic and abiotic environments.

• Ecology is therefore the study of the relationship of plants

and animals to their physical and biological environment.

And the ENVIRONMENT is…

The surroundings of an organism that affect its life and development.

An environment is characterized by the ABIOTIC and BIOTIC

factors.•Abiotic factors are non-living.

•Abiotic factors include: air, water, soil, rock minerals temperature and climate.

•Interactions of abiotic factors result in weather, seasonal changes, tides, air quality, and water quality

An environment is characterized by the ABIOTIC and BIOTIC

factors.

•Biotic factors are living and can be categorized within an

ecosystem structure…

Species Population Community

ECOSYSTEM: all of the communities that live in an area together with the abiotic factors in the environment

List Five Examples of Biotic Factors

1. ___________________________________________________

2. ___________________________________________________

3. ___________________________________________________

4. ___________________________________________________

5. ___________________________________________________

Biotic features are all living things in the biosphere.

• The biosphere is all the parts of Earth that support life.

• This measures approximately 20km thick (12.4 miles)! Most life on Earth exists between 500m below the surface of the ocean and about 6km above sea level.

A dead tree is not

alive but not

considered abiotic….why?

It was once living!

Abiotic and Biotic factors are interconnected….

Geographic location (latitude and longitude) determines

abiotic factors such as temperature and

climate….which in turn, controls or forces a certain type of ecosystem to exist.

What types of

abiotic factors are

influencing these

ecosystems?

An organism’s niche

• Habitat: the actual place an organism lives

• Niche: both living and non-living parts of an ecosystem that determines an organism’s role in the ecosystem.

• If two species share the same niche, they will have various interactions.

• How can species interact?

• These relationships are complex. Each population of species interacts with other species, or biotic factors, as well as with the all of the abiotic factors.

• The niche of an organism and it’s interactions is determined by where it stands in the food web of the ecosystem.

-Producers

-Consumers

-Decomposers

-Scavengers

Producers

•Producers are autotrophic organisms that make their own food.• Phototrophic organisms

use photosynthesis and contain chlorophyll

(Carbon Dioxide + Water + Sunlight =Sugar + Oxygen)

• Chemotrophic organisms use chemicals other than H20, such as H2S

PRODUCERS!!!

ConsumersConsumers are heterotrophic organisms that cannot

make their own food. They must ingest (eat) other organisms.

-Herbivores feed on vegetation (producers).

-Carnivores feed on herbivores or on other carnivores.

Secondary carnivores feed on herbivores,

Tertiary consumers feed on other carnivores

-Omnivores feed on both producers and consumers

-Scavengers feed on dead organisms

CONSUMERS!!!

Scavengers feed on CARRION (dead or

injured animal corpses) and dead plant

biomass. Scavengers reduce the size of

dead organic matter…Decomposers will

finish the job!

DECOMPOSERS recycle small, often

microscopic bits of dead organic matter into

inorganic nutrients availbe for plants to take

up from the soil. Decomposers RECYCLE

nutrients!

BACTERIA and FUNGI are

decomposers…most worms are plant

decomposers!

Energy in the Ecosystem

•Energy from the sun enters and ecosystem when producers used the energy to make organic matter through photosynthesis.

•Glucose is the primary energy source (carbohydrate) produced by photosynthesis.

•Consumers take in this energy when they eat producers or other consumers.

Food Chains

A Food CHAIN is a series of organisms that transfer food between the trophic levels of an ecosystem using only one species at each level…a simple chain.

• The arrows represent the flow of energy from one organism to the next.

• The arrow points toward the organism doing the ‘eating’.

The Ten Percent Law•Most of the energy that enters through

organisms in a trophic level does not become biomass. Only energy used to make biomass remains available to the next level.

•When all of the energy losses are added together, only about 10% of the energy entering one trophic level forms biomass in the next trophic level. This is known as the 10 percent law.

MORE Ten Percent Law•The 10 percent law is the main reason that most food chains have five or less links. Because 90 percent of the food chain’s energy is lost at each level, the amount of available energy decreases quickly.

10 PERCENT

LAW!!

Trophic levels• Trophic levels are the different

feeding levels of organisms in an ecosystem. Producers are the first trophic level and consumers make up several more.

• These relationships can be seen in an ecological pyramid.

• Biomass: the total amount of organic matter present in a trophic level. The biomass in each trophic level is the amount of energy- in the form of food- available to the next trophic level.

Ecological pyramid

PRODUCERS = Autotrophic Plants

Primary Consumers= HERBIVORES

Secondary Consumers= CARNIVORES

EATING HERBIVORES

Tertiary Consumers= CARNIVORE EATING

OTHER CARNIVORES

Food Webs

Ecosystems are not as simple as shown and not often explained by a single food chain… Food WEBS more accurately show the network of food chains representing the feeding relationships among organisms in an ecosystem.

•Most organisms feed on more than one type of organism at different trophic levels.

How do Food Webs show complexity?

•The diversity and stability of an ecosystem is represented by more complex webs that have many species and many interactions (lots of arrows) because they are more stable…more resistant to disturbance by natural disaster or human interference.

•Why?

LESSON 3: PATTERNS OF INTERACTIONS

Relationships in the Ecosystem

• Predator/Prey: One organism (predator) will actively hunt and consume another (prey).

•Competition: two or more organisms of same or different species compete to use the same limited resources or basic needs

• Identify an animal that may compete with the fox for the rabbit.

•Parasitism: an organism (parasite) lives in or on another (host) and feeds on it without immediately killing it

•Mutualism: a cooperative partnership between two species (both benefit)

•Commensalism: a relationship where one species benefits and the other remains unaffected

Symbiotic Relationships

Competition For Resources

What do living things need for survival?

Generate a list of the things that all living things must have for survival.

The Needs of Living Things• All living things from spiders, to

sunflowers, to humans need…

1)Food

2)Water

3)Habitat

4)Air (gas exchange)

• .

COMPETITION

•Organisms compete for shared or limited resources such as food, water, space, and habitats.

•No two species can occupy the exact same niche for very long

Interspecific competition is the competition between member of two different species.

The result is that neither species can obtain as many resources as they could in the absence of the other species.

Intraspecific competition is the competition between member of the same species.• This also includes the competition

for mates.

COMPETITION

How Does Competition Affect Populations?

•A population can not continue to grow indefinitely.

•Limited resources, causes competition among living things for those resources.

•Competition limits the growth of a population.

•Only the fittest survive!