Ecology

Ecology
Ecology: the study of the
interactions among living things
and their surroundings.
Ecological Levels of
Organization
1. Biomes Most Complex

2. Ecosystems
3. Communities
4. Populations
5. Organisms
Simplest
1. Biomes-most complex
 Biome: major biological community
that occurs over a large area of land.
Characteristics of a Biome
No distinct boundaries
Similar organisms
Similar climate conditions
May be located in a totally different
part of the world ( Africa and Asia)
Land biomes & Water biomes
 marine or freshwater
 2. Ecosystems
Ecosystem: All biotic and abiotic
factors in an area.
 Habitat: environment that a species
prefers
2. Ecosystems-Biotic vs Abiotic
Bioticfactors: living things. Each
organism plays a particular role in
the ecosystem.
 Ex) Plants, animals, fungi, bacteria
Niche: the role or “job” an organism
fills.
2. Ecosystems-Biotic vs Abiotic
Abiotic Factors: nonliving things.
Balance of these factors determines
what living things can survive in that
area.
 Ex) moisture, temperature, wind, sunlight, soil
2. Ecosystems & Biodiversity
Biodiversity:Collection of different
living organisms in an ecosystem.
More biodiversity in an ecosystem,
the greater it’s stability & resiliency
2. Ecosystems & Organisms
 Keystone Species: Organisms with an
unusually large effect on its ecosystem.
 Ex: Beavers
 Fellingtrees to construct dams changes streams
into ponds, wet lands, or meadows.
2. Ecosystems & Trophic Levels
 Trophic
Level: levels of energy in an
ecosystem.
 Level 1: Producers
 Level 2: Primary consumers
 Level 3: Secondary consumers
 Level 4: Tertiary consumers
 Level 5: Quaternary consumers
2. Ecosystems & Organisms
Less organisms at higher trophic levels.
 Think of bugs vs. people
 Carrying Capacity: Maximum number of
organisms an ecosystem can support.
 3. Communities
 Community: All the different
populations living in a particular area
 DOES NOT include the abiotic factors
3. Communities &
Ecological Succession
Ecological
succession: the change of
a community over time.
3. Communities &
Ecological Succession
 Steps of Succession:
1. Pioneer species: First species = Lichens
2. Secondary species = grass, small plants
3. Tertiary species = weeds, shrubs
4. Quaternary species = shallow trees (pine)
5. Quinternary species = deciduous trees
 Climax Community: stable community with
diversity (organisms at all levels).
3. Communities &
Ecological Succession
 Primarysuccession: communities form in
essentially lifeless areas.
Fresh lava flow or rocks from a glacier
3. Communities &
Ecological Succession
 Secondary succession: communities form in
areas that have been disturbed.
Forest fire or logging

No pioneer species. Succession begins

with grasses and small plants.
4. Populations
 Population:
All the members of the
same species that live in one place at
a time.
4. Populations- Changes
Changes: Used to make predictions.
Also used to describe & understand
what happens in a natural system
4. Populations - Predictable
Changes  Climate patterns
 Global Warming
 Seasonal reproductive cycles
 Fall- trees lose leaves
becoming dormant
 Population cycles
 Birth rate, death rate
 Immigration, Emigration
 Migrations
 Birds, butterflies
4. Populations- Unpredictable
Changes
Human intervention
Introduction
of Invasive species
Human destruction of ecosystems
5. Organisms
Organism: An individual living thing.
 Simplest level of organization
 5 Organisms

4 Populations

3 Communities

2 Ecosystems
1 Biome
Flow of
Energy
Food Chains & Energy Flow
 Energy is lost between trophic levels.
 Growth, movement, maintenance/repair
 Ruleof 10: Only 10%
of the energy is
transferred to the
next trophic level.
1 hawk
10 snakes
100 mice feed
1000 plants feed
Food chains & Energy Flow
Primary source of energy for
ecosystem is the SUN
All organisms need energy to carry out
daily functions.
Energy flows from: Sun Producers 
Herbivores  Omnivores  Carnivores
Food Chains
Food Chain: sequence that links
species by their feeding
relationships.
 Food webs contain several food chains.
 Arrows show the flow of energy.
 Point to who is doing the eating.
Food Chains
Producers: Get their energy from
the sun & make their own food.
Also called autotrophs
Plants, algae, some kinds of bacteria
Food Chains
Decomposers: Break down
organic matter into simpler,
reusable compounds.
Return vital nutrients to the
environment.
Bacteria & fungi
Food Chains
Consumers: Get their energy from
eating other living or once-living
resources.
Also
called heterotrophs
Humans, animals, insects, etc
Food Chains-
Types of Consumers
Primary Consumer: eat producers
Classified as Herbivores: eat plants
or “producers”
Food Chains-
Types of Consumers
Secondary Consumer: eat primary
consumers & producers
Classified as Omnivores: eat
both plants and animals
Food Chains-
Types of Consumers
Tertiary Consumer: eat primary
and secondary consumers
Classified as Carnivores: eat meat
Food Chains-
Types of Consumers
Quaternary Consumer: eat tertiary
consumers
Also called top predators,
scavengers, or detrivores who eat
dead stuff.
Millipede, ants, vultures
Food Chains-
Biological Magnification
 BiologicalMagnification: Build-up of toxins in
living organisms.
 Moves up the trophic levels
 Toxins collect at the top because those
organisms eat so much.
 Ex: DDT. Methyl Mercury
Food Chains vs Food Webs
 Very few animals
feed on only one
food source.
 Food webs are a
more accurate
picture of how
animals feed.
Food Webs
Food Web: model that shows the
complex network of feeding
relationships and the flow of energy
within an ecosystem.
Food webs
contain several
food chains.
Food Chain/Food Web
Ecological
Relationships
Ecological Relationships
 Competition—when two or more
organisms rely on the same
environmental resource.
Ecological Relationships
 Predation—behavior of one animal
feeding on another
Ecological Relationships
 Symbiosis—the close relationship of
two dissimilar organisms
 3 Types:
1. Commensalism
2. Parasitism
3. Mutualism
Ecological Relationships
1. Commensalism—a symbiotic
relationship where one organism
benefits and one does not benefit but
is unharmed
 Barnacles, birds riding on animals
Ecological Relationships
2. Parasitism—a symbiotic
relationship where one organism
benefits and one is harmed
 Fleas,
mosquitos, liver flukes,
roundworms
Ecological Relationships
3. Mutualism—a symbiotic
relationship where both organisms
benefit
 Wildbirds eating bugs off of zebras
 Bees pollinating flowers
 Clownfish & Sea anemone