Download Environmental Science Unit 2

Environmental Science
Unit 2 – Ecological Interactions
4.1 Roles of Living Things
Objectives
• Identify the roles of producers, consumers
and decomposers
• Describe the
concept of tropic
level.
Chapter 4 Role of Living Things
Producers: Photosynthesizing organisms
Consumers: any organism that can’t make its own
food
1.
2.
3.
4.
Herbivore – eats only plants
Carnivore – eats only herbivores or other carnivores
Omnivores - eats either producers or consumers
Scavengers – feed on bodies of dead organisms
Levels of consumers :
Primary – eats plants
Secondary – eats animals that eat
plants
Tertiary – eat animals that eat animals
that eat plants
Decomposers: An organism that primarily feeds
on dead organisms or the waste from living
organisms mainly bacteria and fungi
Trophic Levels
A layer in the structure of the feeding level of a systems
Heterotrophs: eat
other organisms
Autotrophs: make
their own food
4.2 Ecosystem Structure
Objectives
• Describe food
chains and food
webs.
• Examine the
effects of ecosystem
structure on
population size and
pollution.
Chapter 4 Ecosystem Structure
Food Chain: a series of organisms that
transfer food between the tropic levels of
an ecosystems
Food Web: a
network of
food chains =
not simple !
Chapter 4 Interconnections
Example:
1. Whales were
over hunted
2. Their primary
food source
(krill) became
over abundant.
3. More krill
meant more
penguins & seals
Chapter 4 Diversity and Stability
Which food web
represents a more
mature ecosystem?
Which food web is
more stable?
Chapter 4 Biological magnification
There are increasing concentrations of
pollutants in organisms at higher trophic
levels of food webs
4.3 Energy in the Ecosystem
Objectives
• Investigate the movement of energy
through an ecosystem.
• Define
ecological
pyramid, and
explain its
relationship to
energy in an
ecosystem.
Energy and Food
Producers use little of the sunlight that reaches
them, the energy captured is used to make cells in
both producers and consumers. The total amount of
organic matter present in a trophic level is
called biomass.
10% Law
10% Law is the main reason most food chains have
five or less links. In this example – the biomass
of the owl population simply could not support
another level.
Ecological Pyramid
Ecological Pyramid is a diagram that shows the
relative amounts of energy in different trophic
levels in an ecosystem.
Biomass Pyramid
Ecological Pyramids can show the biomass and numbers
(of organisms) as well as energy.
4.4 Chemical Cycles
Objectives
• Describe the chemical composition of the
human body.
• Explain the
water cycle, the
carbon cycle
and the
nitrogen cycle.
The Human Body
4 elements make
up 96% of your
body.
• Oxygen 65%
• Carbon 18.5%
• Hydrogen 9.5%
• Nitrogen 3.5%
the rest ~4%
The Water Cycle
The Carbon Cycle
The Nitrogen Cycle
Chapter 4
Chapter 5.1 Habitats & Niches
•Describe the concept of niche.
•Examine how interactions between a species
and its environment define the species’ niche.
Chapter 5.1 Niches
Niche refers to a populations role in its
ecosystem
•food
•habitat
•reproduction method
Chapter 5.1 Niche influence
includes both
Biotic
•Competitors
•Predators
•Decomposers
•Population Density
Abiotic
•Soil pH
•Soil Humidity
•Soil
Temperature
•Air Temperature
•Wind Speed
•Sunlight
Intensity
•Soil Nutrients
Chapter 5.1 Competitive Exclusion
Ants
Hawks
Owls
Crickets
Overlapping niches –
species can coexist
Both species share the
same niche – one will
disappear
The extinction of a
population due to direct
competition with another
species for resources is
Chapter 5.1 Niche Diversity
Predator is an organism that actively hunts other
organisms.
Keystone predator is an animal that causes a large
increase in the diversity of its habitat.
Chapter 5.2 Evolution and Adaptation
•Explain how a
species adapts to
its niche.
•Describe
convergent
evolution and
coevolution, and
relate each to the
concept of niche.
Chapter 5.2 Evolution
Evolution,
changes in a
population of
organisms over
time.
Chapter 5.2 Evolving to the
Niche
Populations evolve
by adapting to
niches in the
environment,
dividing available
resources (avoiding
competition)
Specialized species
vs.
Generalized species
Chapter 5.2 Specialized
Specialized
A species closely fit
species vs.Generalized species
Generalized
A species that can
to a specific environment
survive in a variety of
and able to tolerate
ecological niches.
little change in that
environment.
Ex: Koala feed on
Eucalyptus
Ex: Humans
Chapter 5.2 Convergent Evolution
Convergent Evolution, is development of
similar adaptations in two separate species
with similar niches
Chapter 5.2 Coevolution
Coevolution, species which interact
closely and adapt to one-and-other
(even predator & prey) - evolve
together
Chapter 5.3 Populations
Unchecked populations growth leads to
exponential growth
Chapter 5.3 Populations
A population’s limit as defined by its
ecosystem is its carrying capacity
Chapter 5.3 Limiting Factors
Density-independent
limiting factors
Human
Disturbance
Natural
Disasters
Climate
Predation
Population
Size
Water
Availability
Living
Space
Parisitism
Disease
Food
Competition
Density-dependent limiting factors
Chapter 5
Environmental Science
Chapter 6 - Ecosystem
Balance
Chapter 6.1 Relationships in the Ecosystems
Objectives
•Explain the relationship size
between populations sizes of
predator and prey
•Define symbiosis and state the
effects of symbiotic
relationships on populations
Chapter 6.1 - Predator and Prey
Predator – a consumer that actively hunts
and prey – organisms upon which predators
feeds
Chapter 6.1 - Predator and Prey Population Cycles
The populations of predator and prey are
closely linked.
Snowshoe hare =
Lynx = N2
N1
Chapter 6.1 - Parasitism
Parasitism – one organism feeds on the
tissues or body fluids of another
Eyelash Mite
Keys to Parasite survival
1. Eat enough to live and reproduce
2. But not so much that you kill your
host
Chapter 6.1 - Symbiosis
Symbiosis –
a relationship where two species live
together closely. Parasitism is an example of symbiosis.
Commensalism
Mutualism
• One species benefits,
and neither helps nor
harms the other
• Both species benefits
Chapter 6.2 Ecological Succession
Objectives
•Describe the process of primary and
secondary succession
•Illustrate the evolution of many species
from a single ancestor during the process
of island succession
Chapter 6.2 Ecosystem Successions
Primary Succession
• Sequence of
communities forming in
an originally lifeless
habitat
Chapter 6.2 Lichens
Lichens
• A fungus and an algae
living in a mutualistic
relationship
• Important because able
to break down bare
rock using stored acid
• Pioneer community
Chapter 6.2 Climax Community
Climax community
• Community that does not undergo further succession
Chapter 6.2 Secondary Community
Secondary
community
• Succession that
occurs when a
community has
been cleared by a
disturbance, but
does not disturb
the soil
Chapter 6.2 – Other Successions
Aquatic Such as what
might happen in an
oxbow lake
Darwin’s Finches
Island succesion, birds
often populate unfilled
niches.
Chapter 6.3 Balance in the Ecosystem
Objectives
•Examine the concepts of ecosystem
balance and explain how humans affect
that balance.
•Explain that disturbance is a natural part
of all ecosystems, but that disturbances
trigger changes in ecosystems.
Chapter 6.3 Balance in the Ecosystem
All natural ecosystems are stable, they
maintain a state of balance called
equilibrium.
Food-web is heart of
the system
Humans build houses such that salamanders vernal
pools are eliminated, what might happen?
Chapter
6.3
Human
affect on
Balance
VOID
Chapter 6.3 Balance Cause/Effect
Cause
effect
Extinction of dinosaurs
Rapid evolution of
mammals
Chapter 6.4 Land Biomes
Objectives
•Define the concept of a biome and name
the eight major biomes.
•Illustrate where each of the eight major
biomes occurs.
Chapter 6.4 Biomes
Biome a major type of ecosystem with distinct temperature, rainfall & organisms
Chapter 6.4 Forest Biomes
Forest Biomes account for 75% of earth’s
biomass
Receive abundant precipitation
• Coniferous (sometimes refered to as ‘taiga’)
• Deciduous
• four distinct seasons, spring, summer,
autumn, and winter.
• Rain
• Only account for 6% of earth’s land mass,
but contain > 50% of earth’s species
Chapter 6.4 Desert and Tundra Biomes
Desert Biomes account for 25% of earth’s
surface
Contain only 1% of earth’s biomass
Receive little precipitation
• Desert
• Tundra
• Did you know that the Arctic Tundra is
the world's youngest biome?
Chapter 6.4 Grasslands
Grassland Biomes account for 22% of earth’s surface
Contain only 8% of earth’s biomass
Receive less precipitation than forest (may have long dry season)
• Steppe
• dry, cold, grassland
• Prairie
• dominated by herbaceous plants and
grasses.
• Savanna
• two very different seasons
Chapter 6.1 – Quiz (5pts)
1.Red-tailed Hawks feed on chipmunks,
what is the chipmunks role in this
relationship?
2.What is the Red-tailed Hawk’s roles?
3. If the population of snowshoe hares
were to suddenly decline , what would
you expect to happen to the lynx
population?
Compare & Contrast
Types of Symbiosis
Alike
Types
Commensalism
Mutualism
Parasitism
All involve
close
interaction
between two
(or more)
species.
Different
Host
Prey
No effect
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