UNIT 3: COMMUNITIES AND POPULATIONS

Communities & Interactions

Lesson Objectives• Define community as it relates to ecology.• Describe predation and its effects on population size and evolution.• Explain why interspecific competition leads to extinction or greater specialization.• Compare and contrast mutualism, commensalism, and parasitism.• Outline primary and secondary succession, and define climax community.

Content Standard 4: BiodiversityStandard 4: The Interdependence of Organisms in an environment includes the interrelationships and interactions between and among organisms. 1. Organisms both cooperate and compete

in ecosystems (e.g., symbiotic relationships).

2. Living organisms have the capacity to produce populations of infinite size, but environments and resources limit population size (e.g., carrying capacity, limiting factors, ecological succession).

What Will I know and be able to do:

I will know what makes up a community

I will know how energy flows in a community by producing a food web

I will be able to label all biotic and abiotic factors in my community

I will explain to at least two other people my food web

Communities Communities are all the biotic factors

of an ecosystem. This includes all the living plants and

animals.

Food Webs and Chains Food Web: Is

the natural interconnection of all organisms linked with arrows in the order of what-eats-what in a specific community.

Community Food Chain Materials Needed: Blank Paper, scissors,

glue, colors or colored pencils, pictures of your choice.

Directions: Use pictures and colors to make a community with an accurate food chain.

Label the biotic and abiotic factors in your community.

Example on the board

Three Community Interactions

Predation Relationship where one species (predator)

consumes another species (prey)

Competition Compete for the same resources in the same place

Symbiosis Relationship where at least one species benefits 3 types: mutualism, commensalism, parasitims

Three community interactions

Predation –this is where members of one species (predator) consume members of another species (prey).

Predator/Prey Predator/Prey - Keeps populations of

both species in balance.

Keystone Species This is a species within a community that

is the only predator to another species. In the event that this predator

population dies out the prey will over grow and eventually die out causing then other species in the community to die out.

Adaptations to Predation Predators develop adaptations to help

them capture prey. Prey develop adaptations that help them

to avoid prey.

Competition Intraspecific occurs between members

of the same species. (competing for mates). How species evolve to become better

adapted to survive

Interspecific occurs between different species

(competing for the same prey) May lead to extinction May lead to specialization

Competition

Intraspecific competition

Interspecific can lead to

Extinction – die out Specialization – evolve

Interspacific competition

Symbiosis Three relationships within an ecosystem

were at least one organism benefits.

Mutualism – both organisms benefit Commensalism – one benefits, other not

harmed Parasitism – one benefits, other is

harmed

Mutualism

Commensalism

Parasitism

Symbiosis – at least one benefits

Tree Niche

Aquatic Niche