Transcript Ecology - Choteau Schools

Ecology
The study of interactions that take
place between organisms and
their environment.
Chapter 2
Principles of Ecology
Sections 1 and 2
Organisms and Their Environment
Nutrition and Energy Flow
What is the biosphere?
• Portion of Earth which supports living things.
• Includes both abiotic and biotic factors.
What are abiotic factors?
• The nonliving parts of an organism’s environment.
– Air currents, temperature, moisture, light, soil
What are biotic factors?
• All living organisms which inhabit an
environment.
Levels of Organization
•
•
•
•
•
Organism
Population
Biological Community
Ecosystem
Biosphere
Interactions within Populations
• Population
– Group of organisms of the same species which
interbreed and live in the same area at the same time.
– Some organisms form adaptations to decrease the
amount of competition within the population.
Interactions Within Communities
• Biological Community
– Made up of interacting populations in a certain
area at a certain time.
– A change in one population in a community may
cause changes in the other populations.
Ecosystem
• Made up of interacting populations in a biological
community and the community’s abiotic factors.
• Two major types of ecosystems
– Terrestrial – located on land
– Aquatic – locate in both fresh- and saltwater
What is a habitat?
• The place where an
organism lives out its life.
• Niche
– the role or position a
species has in its
environment
– How an organisms meets its
needs for food and shelter,
how and where it
reproduces and survives.
– May change over the life of
the organism.
Symbiosis
• A close and permanent association
between organisms of different species.
• 3 Types
– Mutualism
– Commensalism
– Parasitism
Mutualism
• Both species benefit from the relationship
Commensalism
• One species benefits
and the other species
is neither harmed nor
benefited.
Parasitism
• Harmful to one
species yet benefits
the other.
How do organisms obtain energy?
• Producers – Autotrophs
– Organism that use light
energy or energy stored in
chemical compounds to
make energy-rich
compounds.
– Example: Plants use
sunlight to make energy
during the process of
photosynthesis.
How do organisms obtain energy?
• Consumers – Heterotrophs
– Organisms which cannot make
their own food and so have to
feed on other organisms.
– Five main types of consumers.
Herbivores
– Heterotrophs that eat
only on plants.
Carnivores
– Heterotrophs which
eat heterotrophs.
Omnivores
– Heterotrophs that eat
both plants and
animals.
Scavengers
– Heterotrophs which eat animals which have already died.
Decomposers
• Break down the
complex compounds
of dead and decaying
plants and animals
into simpler
molecules which can
be more easily
absorbed.
How Do We Chart the Flow of Matter
and Energy in an Ecosystem?
• Food Chain – A model
which shows one way in
which matter and energy
move through an
ecosystem.
– Arrows indicate the
direction of energy transfer.
– Each time energy is
transferred, part of the
energy is given off as heat.
• Each organism in a food
chain represents a
feeding step, or trophic
level, in the passage of
energy and materials.
• First order heterotroph –
Feeds on plants
• Second order heterotroph
– feeds on a first order
heterotroph
Food Web
• Shows all possible feeding relationships at
each trophic level in a community.
Ecological Pyramid
• Another way to show the flow of matter and
energy in an ecosystem.
Pyramid of Numbers
Pyramid of Energy
(Energy decreases at each trophic
level in the pyramid through uneaten
organisms and heat given off to the
environment.)
Pyramid of Biomass
(Biomass is the total weight of living
matter at each trophic level.)
Matter
• The biosphere contains a fixed amount of
water, carbon, nitrogen, oxygen, and other
materials required for life.
• These materials are cycled through the
biosphere and used by many different
organisms.
Water Cycle
• A model that describes how water moves
from the surface of the earth to the
atmosphere and back to the surface again.
Water Cycle
• Components of the water cycle:
– Evaporation
• Occurs when liquid water turns into water vapor (gas).
– Transpiration
• Occurs when plants release water into the air.
– Respiration
• Releases water vapor to the air.
– Animal Wastes
• Returns water to the environment.
– Condensation
• Occurs when water vapor changes to a liquid.
– Clouds
• When water vapor cools, it condenses on tiny particles of matter (like dust) in the air
and forms tiny droplets.
– Precipitation
• Eventually the “cloud” droplets become so heavy that they fall to the earth as
precipitation.
Carbon Cycle
• During photosynthesis, autotrophs use energy
from the sun to convert carbon dioxide into
energy rich carbon molecules.
• The carbon is transferred to heterotrophs
through the food chain.
• Carbon is returned to the
atmosphere as a waste in the
form of carbon dioxide.
• Very slow process.
Nitrogen Cycle
• Plants cannot use nitrogen directly from the
air...so, bacteria in the soil convert the
nitrogen from the air into compounds that
plants can use.
• Animals get the nitrogen they need by eating
plants.
• Nitrogen is returned to the
environment through animal
wastes and dead and
decaying organisms.
Phosphorous Cycle
• Short-term Cycle:
– Plants obtain phosphorous from the soil.
– Animals get the phosphorous by eating the plants.
– Phosphorous is returned to the soil through decomposing
dead organisms.
• Long-term Cycle
– Phosphates that are washed into
water become trapped in rocks as
insoluble compounds.
– As the rock erodes over millions of
years, the phosphorous is released
back into the environment.