Download 13.1 Ecologists Study Relationships

13.1 Ecologists Study Relationships
KEY CONCEPT
Ecology is the study of the relationships among
organisms and their environment.
13.1 Ecologists Study Relationships
Ecologists study environments at different levels of
organization.
• Ecology is the study of the interactions among living
things, and between living things and their surroundings.
Fig. Salmon are a
primary food source
for many species,
including grizzly
bears. If salmon
disappeared, species
dependent on them
would also suffer.
13.1 Ecologists Study Relationships
• An organism is an individual living
thing, such as an alligator.
Organism
Organism
13.1 Ecologists Study Relationships
• A population is a group of the same
species that lives in one area.
Population
Population
Organism
Organism
13.1 Ecologists Study Relationships
• 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
• 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
• A biome is a major regional or global
community of organisms characterized
by the climate conditions and plant
communities that thrive there.
Biome
Ecosystem
Ecosystem
Community
Community
Population
Population
Organism
Organism
13.1 Ecologists Study Relationships
Ecological research methods include observation,
experimentation, and modeling.
• Observation is the act of carefully watching something over time.
• Observations of populations can be done by visual surveys.
– Direct surveys for easy to spot
species employ binoculars or scopes.
– Indirect surveys are used for
species that are difficult to track and
include looking for other signs of
their presence.
Fig. Much of the data gathered by ecologists results
from long hours of observation in the field. This
ecologist is using radio telemetry to track coyotes.
13.1 Ecologists Study Relationships
• Experiments are performed in the lab or in the field.
– Lab experiments give researchers more control.
– Lab experiments are not reflective of the complex
interactions in nature.
– Field experiments give a
more accurate picture of
natural interactions.
– Field experiments may
not help determine
actual cause and effect.
13.1 Ecologists Study Relationships
KEY CONCEPT
Every ecosystem includes both living and nonliving
factors.
13.1 Ecologists Study Relationships
A Brief Review from August:
• Biodiversity is the assortment, or variety, of living things in
an ecosystem.
• Biodiversity increases as you travel from the poles to the
equator.
13.1 Ecologists Study Relationships
Biotic factors are living things.
– plants
– animals
– fungi
– bacteria
13.1 Ecologists Study Relationships
• Abiotic factors are nonliving things.
– moisture
– temperature
– wind
– sunlight
– soil
13.1 Ecologists Study Relationships
• A keystone species is a species that has an
unusually large effect on its ecosystem.
keystone
13.1 Ecologists Study Relationships
• Keystone species form and maintain a complex web of
life.
creation of
wetland
ecosystem
increased waterfowl
Population
keystone species
increased
fish
population
nesting
sites for
birds
13.1 Ecologists Study Relationships
Every organism has a habitat and a niche.
13.1 Ecologists Study Relationships
A habitat differs from a niche.
• A habitat is all
aspects of the
area in which an
organism lives.
• This includes all
biotic and
abiotic factors
13.1 Ecologists Study Relationships
A habitat differs from a niche.
• An ecological niche is
– The role and position a
species has in its
environment
– How it meets its needs for
food and shelter
– How it reproduces
– Its behavior
– All its interactions with the
biotic and abiotic factors
of its environment
13.1 Ecologists Study Relationships
Example: The niche of black bears
• Ecological role: Helps carry
seeds of berries (in their
digestive systems) and
expels them, allowing the
berries to grow
• Finds shelter in the forest
• Feeds on nuts, berries,
insects, and small animals
• Fed on by blood-sucking
insects and parasites
13.1 Ecologists Study Relationships
Resource availability gives structure to a community.
• Species can share habitats and resources.
– This leads to competition
13.1 Ecologists Study Relationships
• Two species can NOT share the same niche
– This is known as competitive exclusion
• Competitive exclusion has
different outcomes.
–One species is better
suited to the niche and the
other will either be pushed
out or become extinct.
–The niche will be divided.
–The two species will
further diverge
13.1 Ecologists Study Relationships
• Ecological equivalents are species that occupy similar
niches but live in different geographical regions.
Madagascar
South America