13.1 Ecologists Study Relationships
KEY CONCEPT
Ecology is the study of the relationships
among organisms and their environment.
New Vocab:
• Ecology
• Community
• Ecosystem
• Biome
Review Vocab:
• Organism
• Population
13.1 Ecologists Study Relationships
Main Idea 1:
Ecologists study environments at different levels of
organization.
• Ecology is the study of the interactions
(relationships) among living things, and between
living things and their surroundings.
– Studying how life interacts within the biosphere.
• Scientists used to study each organism separately
as if they existed in isolation.
13.1 Ecologists Study Relationships
Levels of Organization
(There are 5 levels)
However, now scientists study nature on
different levels, from local to a global
scale. This organization reveals the
complex relationships found in nature.
13.1 Ecologists Study Relationships
First level:
• An organism is an individual living
thing, such as an alligator.
Organism
Organism
13.1 Ecologists Study Relationships
Second level:
• A population is a group of the same
species that lives in one area.
• What can cause populations to
change?
Population
Population
Organism
Organism
13.1 Ecologists Study Relationships
Limiting Factors of
Populations
– Birth & death rates
eventually balance
Factors: Disease, food, predators,
climate, space, mates
• Carrying Capacity:
Greatest number of
individuals that a population
can sustain
– What stage is the human
population in?
13.1 Ecologists Study Relationships
Human Population: Fast Growth
• How have
Stage
humans
extended
our
carrying
capacity?
• Farming
• Medical
innovations
• Clean
water
• Public
assistance
13.1 Ecologists Study Relationships
Third level:
• A community is a group of different
species that live together in one area.
Community
Community
Population
Population
Organism
Organism
13.1 Ecologists Study Relationships
Fourth level:
• An ecosystem includes all of the
organisms as well as the climate, soil,
water, rocks and other nonliving things
in a given area.
Ecosystem
Ecosystem
Community
Community
Population
Population
Organism
Organism
13.1 Ecologists Study Relationships
Fifth level:
Biome
• A biome is a major regional or global
community of organisms characterized
by the climate conditions and plant
communities that
Ecosystem
thrive there.
Ecosystem
Community
Community
Population
Population
Organism
Organism
13.1 Ecologists Study Relationships
Basically, a biome is a large area with distinct climate,
plant, and animal life.
• Climate factors
that affect
biomes: sun,
rain,
topography
• Climate
determines
life.
13.1 Ecologists Study Relationships
KEY CONCEPT
Every ecosystem includes both living and
nonliving factors.
New Vocab:
• Biotic
• Abiotic
• Biodiversity
• Keystone
Species
13.1 Ecologists Study Relationships
Main Idea 1:
An ecosystem includes both biotic and abiotic factors.
• Biotic factors are
living things, like:
– plants
– animals
– fungi
– Bacteria
• Bio = Life
•
If something has life,
then it is living.
plants
13.1 Ecologists Study Relationships
• Abiotic factors are nonliving things, like:
– moisture
– temperature
– wind
– sunlight
– soil
– rocks
•
A = Without Bio = Life
• If something does not
have life, then it is not
living.
• The balance of these
factors determines what
can live in a particular
environment.
sunlight
moisture
13.1 Ecologists Study Relationships
Main Idea 2:
Changing one factor in an ecosystem can affect many
other factors.
An ecosystem is a complex web of connected biotic and abiotic
factors.
• Biodiversity is the assortment, or variety, of living things
in an ecosystem.
– The amount of biodiversity in an ecosystem depends on
many factors.
– Rain forests have more biodiversity than other locations
in the world, but are threatened by human activities.
– Why is this?
13.1 Ecologists Study Relationships
• A keystone species is a species that has an
unusually large effect on its ecosystem.
– Because there are complex relationships within
an ecosystem, a single change (a few broken
strings in a web) in biotic or abiotic factors
could have a variety of effects.
What would happen if the keystone in the arc was missing?
keystone
13.1 Ecologists Study Relationships
• Here is an example of a Keystone species and how they
form and maintain a complex web of life.
creation of
wetland
ecosystem
increased waterfowl
Population
keystone species
increased
fish
population
nesting
sites for
birds