Symbiosis, Food Webs and Limiting Factors

Symbiosis, Food Webs,
Limiting Factors

SC.7.L.17.2: Compare and contrast the relationships among organisms,
such as mutualism, predation, parasitism, competition, and
commensalism. (Also assesses SC.7.L.17.1 and SC.7.L.17.3.)
SC.7.L.17.1: Explain and illustrate the roles of and relationships among
producers, consumers, and decomposers in the process of energy transfer in
a food web.
SC.7.L.17.3: Describe and investigate various limiting factors in the local
ecosystem and their impact on native populations, including food, shelter,
water, space, disease, parasitism, predation, and nesting sites.

Essential Question:
What relationships can exist
between organisms in
ecosystems and how do
organisms interact in order
to survive?

I DO GUIDED NOTES

TYPESOF SYMBIOTIC RELATIONSHIPS

• Symbiosis is an interaction between two different

organisms that are in the same ecosystem.

• Types of symbiotic relationships:

● commensalism: one organism benefits while the

other is unaffected

● parasitism: one organism benefits while the other is

harmed

● mutualism: both organisms benefit

OTHER INTERACTIONS IN ECOSYSTEMS

• Competition:
When two or more organisms are trying

to use the same limited resource at the same time.

● Plants competing for sunlight →

• Predation (Predator-Prey): When one organism

kills and eats the other for energy and nutrients.

ENERGY TRANSFERIN FOOD WEBS

• Producers: basis of the food web. Transform light energy into chemical energy

(food) through photosynthesis. Autotrophs (makes own food)

• Consumers: Get energy by consuming other organisms. Herbivores, carnivores, or

omnivores are all heterotrophs (eats others).

● Primary Consumers eat plants and are herbivores.

● Secondary Consumers eat the primary consumers in a food web. (heterotroph)

● Tertiary Consumers eat secondary consumers. Considered a top predator in the

food web. (heterotroph)

• Decomposers: get energy by breaking
down dead organisms.

LIMITING FACTORS:

• Limiting Factors: When there is not enough of one resource

that many populations or individuals need.

• Lack of resources creates competition and can lead to smaller

populations due to organisms leaving the area or dying off.

● Not enough Shelter for organisms to live in.

● Not enough Waterto live in or drink.

● Not enough Space, causing crowding.

● Because organisms are closer, Diseasescan spread easily.

● Organisms are forced to Parasitism to survive.

● Food becomes limited due to environmental or human impact.

● There are fewer Nesting Sites for organisms to keep their

young safe.

WE DO
COLLABORATIVE ACTIVITY