Lecture # 1 Intro to
Ecology & the Biosphere
Breakdown
Unit 7: Ecology
1. We are part of
the environment
along with all of
Earth’s other
organisms.
2. All of Earth’s
inhabitants are
interwoven in a
complex web of
relationships.
3. Interactions
of the parts
affect the
whole system.
4. Removing,
altering, or
damaging one
part of the whole
will affect the
whole.
Many consequences
of doing so are
unpredictable, so
understanding how
the “whole” operates
is critical for
humankind if we are
to survive as a species
on this planet.
Take 2 minutes to summarize why it is
important for humans to pay attention
to the state of our environment
What is ecology?
Ecology- the scientific study of
interactions between organisms
and their environments,
focusing on energy transfer
• It is a science of relationships.
What exactly is ‘the environment’?
Everything that surrounds us!
The environment is made up of two
factors:
Biotic factors- all living organisms
inhabiting the Earth (ex: grass, trees,
rabbits, bacteria, etc)
Abiotic factors- nonliving (physical) parts
of the environment (ex: temperature,
soil, light, moisture, air currents)
Abiotic or Biotic?
Biotic
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Abiotic or Biotic?
Abiotic
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Abiotic or Biotic?
Abiotic
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Organization levels of biology
Biosphere
Ecosystem
Community
Population
Organism
Organism- any unicellular or multicellular
form exhibiting all of the characteristics
of life; an individual.
•The lowest level of organization
Population-a group of organisms of
one species living in the same place
at the same time that interbreed
and compete with each other for
resources (ex. food, mates,
shelter)
Remember from last unit….
Species- Members
of a population
that look alike
and have the
ability to
produce fertile
offspring
Canis lupus
Community- several interacting
populations that inhabit a common
environment and are
interdependent.
Ecosystem- populations in a
community and the abiotic factors
with which they interact
Marine
Terrestrial
Ecosystem= biotic + abiotic factors
• Ecosystem boundaries are not
always obvious. They depend on
how the ecosystem is being studied.
Example - a single rotting log on the
forest floor vs. the entire forest itself.
Biomes- groups of
related terrestrial
ecosystems
Example: rainforest,
grassland, desert
Biosphere- the region on earth
where life exists. This includes air,
land, fresh water, and salt water.
•The highest level of organization
Biodiversity The variety of
species living
within an
ecosystem, biome
or planet.
Some parts of the world have greater
biodiversity than others
Do you think that desert or the rainforest has greater
biodiversity?
Habitat vs. Niche
Habitat- the place in which an
organism lives out its life (address)
Niche - the role a species plays in a
community (job)
Habitat vs. Niche
A niche is determined by the
tolerance limitations of an
organism, or limiting factors.
Limiting factor- any biotic or
abiotic factor that restricts the
existence of organisms in a
specific environment.
Examples of limiting factors
•Amount of water
•Amount of food
•Temperature
Take 2 minutes to summarize how life is
organized according to the ecological
hierarchal system outlined in this
section in notes.