• Entry Task:– What is the difference between a biotic factor and an

abiotic factor?

• Learning Target:– Understand the differences between abiotic/biotic and

the concept of a niche.

• Language Objective:– Describe an ecosystem’s biotic and abiotic factors.

– Describe organism in terms of its habitat and niche.

Factors

• What is a biotic factor?– Any biological influence on an organism.– Includes all other living organisms in the ecological

community.

• What is an abiotic factor?– Any physical, non-living influence on an organism.

• Both determine survival and growth of an organism as well as ecosystem productivity.

Recognizing Factors - QUIZ!!

1. 2. 3. 4.

5. 6. 7. 8.

9. 10.

Habitat

• What is a habitat?– Where an organism lives.– Includes biotic and abiotic factors.– Ex: for a frog, it could be a pond.

Niche

• What is a niche?– Full range of conditions in which an organism

lives, both biological and physical, and how an organism uses these conditions.

• No two species can share the same niche, but niches can be similar.

What’s your niche?

• Make a personal place map. – This will be a brief sketch in your notebook.

• What characteristics make it special to you? – Draw 5 biotic factors and label

– Draw 5 abiotic factors and label

– Does anyone else like this place just the same way as you do? Why is it special only to you?

• Entry Task:– What are the six classifications of community

interactions?

• Learning Target:– Be able to recognize what type of interaction is

occurring in an ecological community.

• Language Objective:– Describe interactions in an ecological community using

the proper terms associated with these interactions.

Competition

• What is competition?– Both organisms want the same thing. Niches

develop as a way to reduce competition.

• Competitive Exclusion Principle:– No two species can occupy the same exact

niche in the same habitat at the same time, so they compete for resources and mates.

Predation

• What is predation?– Interaction in which one organism captures and

feeds on another organism.

• What is a predator?– The organism that feeds on another organism.

• What is the prey?– The organism that gets fed upon by the

predator.

Which is which?

Symbiosis

• What is symbiosis?– Any relationship in which two species live

closely together.– There are three main types of symbiosis

Symbiosis - Mutualism

• What is mutualism?– Both organisms benefit.– Ex: Each June in California's

hot San Joaquin Valley, paper bags containing wasp and pollen-bearing caprifigs are stapled to limbs in Calimyrna fig orchards.

– Ex: Bacteria in an organism’s gut and on its skin usually have a mutualistic relationship with the organism.

Symbiosis - Commensalism

• What is commensalism?– One member of the

relationship benefits, but the other is neither helped nor harmed.

– Ex: Barnacles can be seen on the back of this gray whale. This association doesn’t hurt the whale, but the barnacles get a free ride.

Symbiosis - Parasitism

• What is parasitism?– The relationship harms

one of the members.

– An organism that lives on or in another organism causes direct harm to this “host”

– Ex: Leeches, harmful bacteria, ticks, deer liver flukes

“Community Interactions in the High School” Skits

• Groups of five• On the butcher paper at your station, include the following:

– Definition of your assigned interaction (in your own words). See p.92– Example of your interaction in nature.– Create a short skit involving ALL group members of this interaction

in a high school setting.– YOU HAVE 15 MINUTES…. GO!

1. Competition 3. Mutualism2. Predation 4. Commensalism

5. Parasitism

Relationships in your Niche

• Describe three examples of community interactions seen during today’s skits that take place in your niche (personal place).

• These should be labeled and on the back of your poster for “What’s Your Niche?”

• Entry Task:– What is population density?– What are the two types of population growth?

• Learning Target:– Be able to recognize which type of population growth

is occurring and what might affect population size.

• Language Objective:– Describe population changes using terms such as

population density, immigration, emigration, growth (exponential and logistic), and carrying capacity.

Populations

• What is a population?– A group of individuals in the same area

• What characterizes a population?– Geographic distribution, range (where they are)– Density (individuals per unit area)– Growth rate (how the size of a population changes)– Age structure (Chpt. 5-3)

Population Density

• There are 200 bull frogs living in a pond that covers 4 square kilometers… What is the density of the bull frog population?

– Population density = # individuals / Unit Area

• 200 bull frogs / 4 km2 = 50 bull frogs / km2

Human Population Densities

• Wenatchee: 451/square mile

• New York City: 27, 532/square mile

• Mumbai, India: 1,000,000/square mile

Population Growth

• What affects population size?– # births– # deaths– # of individuals entering (immigration) or

leaving (emigration)

• When does growth occur?– Birthrate > deathrate– Immigration > emigration

Types of Population Growth

• Exponential growth– J-shaped curve, constant rate of growth– Occurs when there are unlimited resources and

no predation or disease. This are known as ideal conditions.

Exponential Growth

Types of Population Growth

• Logistic Growth– Natural populations do not exhibit exponential

growth all the time… – Cases when growth slows or stops:

• As resources decrease• Deathrate = birthrate• Immigration = emigration

– Individuals a given environment can support = Carrying capacity.

Logistic Growth

• Always some fluctuation or slight changes that make it so a population is not AT carrying capacity all the time