1. Unit 2 – Ecosystems and Population Change
Chapter 3 deals with Ecosystems and Diversity. During this chapter we will be going on a field trip to study some of the populations in our area. After that, we will move on to Chapter 4, which deals with the Mechanisms of Population change.
Discuss the information on page 77 regarding the mountain pine beetle. Give students 10 minutes to complete the launch lab (may extend to 15 minutes if the students are working hard).
3.1 – Individuals, Populations, and Communities in Ecosystems
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2. Learning Objectives What is an ecosystem?
What are populations and communities?
How do these fit into ecosystems?
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3. The Parts of an Ecosystem
An ecosystem is made up of many parts.
Ecosystems can take up many hectares of land or can be small, such as a tide pool or a rotting log.
Abiotic factors include air, water, soil, nutrients, and light.
Biotic factors include plants, animals, and micro-organisms.
A habitat is where an organism lives.
The habitat of the red fox often includes the edges of forests or marshlands.
(c) McGraw Hill Ryerson 2007

4. Ecotones
Ecotones
A transition area between ecosystems
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5. Abiotic Interactions in Ecosystems
The abiotic components are what allow the biotic components to survive in an ecosystem.
Abiotic factors include:
oxygen, water, nutrients
light and soil.
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See pages

6. Abiotic factors: Oxygen
Oxygen is produced by the green plants and certain micro-organisms and is used by animals and most other micro-organisms.
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7. Abiotic factors: Water
Water is necessary for all life.
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8. Abiotic factors: Nutrients
Nutrients often enter the food chain with plants and are very important for growth.
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9. Abiotic factors: Light
Light is required for photosynthesis, which is the process in plants that converts and stores the Sun’s energy in the form of starches and carbohydrates.
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10. Abiotic factors: Soil
Soil not only contains water and nutrients but also is home to many plants and animals.
Earthworms
in soil
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11. Individual Organisms How does the environment affect
Behavior?
Physical features (Morphology)?
Helps to explain why some organisms are only present in certain areas
What physical features (morphology) allows this cactus to grow in some environments but not others?
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12. Populations Species Population
Organisms that can breed with each other and produce fertile offspring
Population
A group of individuals of the same species living in a specific area at the same time
Population Ecologists study the changes in populations over time (increase, decrease, stay the same), and what factors determine the relative numbers of males and females or young and old individuals.
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13. Communities Community Interactions affecting communities:
All individuals in all of the interacting populations in a given area
Interactions affecting communities:
Competition
Predator/prey relationships
Symbiotic Relationships
Abiotic factors
Community ecologists study the interactions among the members of different populations
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14. Symbiotic relationships
Symbiotic relationships are the interactions between members of two different species that live together in a close association.
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15. Commensalism Commensalism – one species benefits, one is not affected
Example: Clownfish living in a sea anemone
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16. Parasitism Parasitism – one species benefits, the other is harmed
Example: hookworm living in dogs
A mosquito drinking human blood
A lamprey eel living off a fish
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17. Mutualism Mutualism – both species benefit
Example: a bee gathering nectar from a flower
Birds eating parasites off a rhino.
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18. Niches and Competition
A niche refers to the role an organism has within an ecosystem, physically, chemically and biologically.
Competition occurs when a
resource is needed by two or
more individuals.
Competition usually means
resources are limited.
This limits the size and health of that
individual and perhaps that population.
Coyotes compete over habitat or food sources.
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19. Predation
Predation is the relationship between the “eaters” and the “eaten”.
Predators have adaptations to help them catch their prey.
Prey have adaptations to help avoid predators.
Examples of adaptations include spines and shells, camouflage and mimicry.
The numbers of predators
and prey influence each other.
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20. Biodiversity in Ecosystems
Biodiversity refers to the variety and number of different individuals and species in an ecosystem.
Healthy ecosystems generally
have high biodiversity.
Most biodiversity losses occur
from the loss of habitat.
Wetlands provide habitats.
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21. The impact of Humans on Ecosystems
Humans often have a negative impact on biodiversity.
Many efforts are now made to lessen this impact in order to maintain biodiversity.
Ecological management programs try to balance human progress with maintaining biodiversity.
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22. Environments Change Over Time
Abiotic factors
Biotic Factors
Populations/Communities
Succession
Here are two places where succession occurs. In the salt marsh, new silt is deposited through tidal action, providing great substrate for some types of hardy plants. These grasses thrive for a few years, and eventually completely cover the new land. After the grasses change the soil, other new plants can begin to grow. This trend continues with increasingly larger plants until trees are able to grow. (as seen on the other side of this body of water). The same thing happens in a forest. After a fire, meadow grasses begin to grow. Next come shrubs and other low plants, and eventually trees can begin to take root. With each different type of plant, the soil, light, and wind conditions change, making the environment more hospitable for the new life forms, and less hospitable for the old.
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23. Primary Succession
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24. Earth’s Biosphere Biosphere
All of the ecosystems and their interactions
Atmosphere, Lithosphere, Hydrosphere
Each species has its own niche in the biosphere
They live in specific places and are well suited to survive in these areas
Assignment: After checking out what sites are possible field trip sites, tell the students where we might go and have them complete Thought Lab 3.1 (Planning for your Field Study)
Assign Section 3.1 Review, page 84, #1-8
Assign Case Study (Nelson) Page 88 – Natural and Artificial Ecosystems (this could possibly be part of an assignment for the substitute when I am at the conference)
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25. The Big Picture
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