Download Unit 2 * Ecosystems and Population Change

Unit 2 – Ecosystems
and Population
Change
3.1 – Individuals, Populations, and
Communities in Ecosystems
Mr. Standring
Learning Objectives
• What is an ecosystem?
• What are populations and communities?
– How do these fit into ecosystems?
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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
Ecotones
• Ecotones
– A transition area between ecosystems
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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.
See pages 37 - 38
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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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Abiotic factors: Water
• Water is necessary for all life.
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Abiotic factors:
Nutrients
• Nutrients often enter the food chain with
plants and are very important for growth.
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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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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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Individual Organisms
• How does the
environment affect
– Behavior?
– Physical features
(Morphology)?
• Helps to explain why
some organisms are
only present in certain
areas
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Populations
• Species
– 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
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Communities
• Community
– All individuals in all of the
interacting populations in a
given area
• Interactions affecting
communities:
–
–
–
–
Competition
Predator/prey relationships
Symbiotic Relationships
Abiotic factors
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Symbiotic
relationships
• Symbiotic relationships are the interactions
between members of two different species that
live together in a close association.
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Commensalism
• Commensalism – one species benefits, one is not
affected
• Example: Clownfish living in a sea anemone
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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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Mutualism
• Mutualism – both species benefit
– Example: a bee gathering nectar from a flower
– Birds eating parasites off a rhino.
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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.
Coyotes compete over
– This limits the size and health of that habitat or food sources.
individual and perhaps that population.
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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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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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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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Environments Change
Over Time
• Abiotic factors
• Biotic Factors
– Populations/Communities
• Succession
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Primary Succession
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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
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The Big Picture
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