• 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