Transcript What is Ecology?

What is Ecology?
Mrs. Griffin
Greek origin
 OIKOS = household
 LOGOS = study of…
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Study of the
“house/environment”
in which we live.
Origin of the word…”ecology”
Ecology is study of interactions
between
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non-living components in the
environment…
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light
water
wind
nutrients in soil
heat
solar radiation
atmosphere, etc.
AND…
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Living organisms…
◦ Plants
◦ Animals
◦ microorganisms in soil, etc.
ECOLOGY:
Levels of Organization
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A hierarchy of
organization in
the environment
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Biosphere
◦ Contains the combined portions of the planet in
which all life exists, including land water, and
air or atmosphere.
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Ecosystem
◦ Is a collection of all the organisms that live in a
particular place, together w/ their non-living,
or physical environment.
Levels of organization - Terms
Levels of organization - Terms
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Community – All populations (diff. species) that live in a particular
area.
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Population – groups of individuals that belong to the same species
and live in the same area.
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Species- A group of similar organisms that breed and produce
fertile offspring.
What is the ULTIMATE source of
energy?
Energy Flow
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What is an autotroph?
◦ What are plants, some algae, and certain
bacteria also called?
 Producers- are essential to the flow of energy
through the biosphere.
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What is a heterotroph?
◦ What are heterotrophs also known as?
 Consumers
Heterotrophs Include
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Herbivores
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Carnivores
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Omnivores
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Detritivores
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Decomposers
Feeding Relationships
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Energy flows through an ecosystem
in one direction.
◦ What is that direction?
 From sun or inorganic compounds -> autotrophs
(producers)-> various heterotrophs (consumers).
 Who eats whom?
Food Chains- the energy stored by producers can
be passed through an ecosystem along a food
chain. Organisms transfer energy by eating and
being eaten.
Food Webs- are formed when feeding
relationships in an ecosystem form a network of
complex interactions. Links all food chains in an
ecosystem together.
Each step in a food chain or food web
is called a trophic level. Producers
make up the first…..
Ecological Pyramids
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Used to represent energy
in an ecosystem; shows
relative amt. of energy
w/in each trophic level.
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Only 10% of the energy
available w/in one
trophic level is
transferred to organisms
at the next trophic level.
◦ Why is this so?
 Respiration, movement,
reproduction, & other life
processes.
What Shapes an Ecosystem?
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Includes both biotic and abiotic factors.
◦?
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Together biotic and abiotic factors
determine the survival and growth of
an organism and the productivity of
the ecosystem in which the organism
lives.
◦ What is the area that an organism lives called?
 Habitat, includes both biotic and abiotic factors.
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No two species can share the same niche in the
same habitat: Competitive exclusion
principle- no two species can occupy the
same niche
The Niche (NITCH)- the full range of physical and
biological conditions in which an organism lives and
the way in which the organism uses those
conditions.
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Symbiosis: living together
Community interactions such as
competition, predation, and
various forms of symbiosis can
affect an ecosystem.
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Interspecific: competition amongst two or
more species for limiting resources
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Intraspecific: competition amongst
members of a population.
Intra/Interspecific Competition
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Primary succession: begins with bare
rock exposed by geologic activity
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Secondary succession: begins on soil
from which a previous community
has been removed
Ecological Succession- a series of
predictable changes in a
community over time.
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Limiting nutrients- when an ecosystem
is limited by a single nutrient that is
scarce or cycles very slowly
◦ Fertilizers are used for this reason, usually
contain nitrogen, phosphorus, and potassium
◦ Aquatic systems nutrient rich or poor?
Algal blooms
 Problem?
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Nutrient Limitation
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Three important characteristics of a
population are its geographic
distribution, density, & growth rate
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How big can geographic distribution
(the area inhabited by a population)be?
Populations
The number of
individuals per
unit area
◦ Varies
greatly
◦ Ex. Saguaro
cactus
Population Density
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Three factors can affect population size:
the number of births, deaths, & the
number of individuals that enter or leave
a population
◦ Immigration
◦ Emigration
Population Growth
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Occurs when individuals in a population
reproduce at a constant rate (under ideal
conditions w/unlimited resources)
Exponential Growth, J-curve
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Occurs when a population’s growth stops
slows or stops following a period of
exponential growth
◦ Population growth may
slow down when the
birthrate decreases or
death rate increases, or
both
◦ Carrying capacity- the largest
number of individuals that a
given environment can support
Logistic Growth, S-curve
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Tends to increase over time
Human Population Growth
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Limiting factor- a factor that causes
population growth to decrease :
competition, predation, parasitism, human
disturbances, etc…
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Density-Dependent Factors- a limiting
factor that depends on population size,
include competition, predation,
parasitism, and disease.
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Density-Independent Factors
Limits to Growth
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Competition
Parasitism &
disease
Predation ->
predator-prey
relationships, one
of the best-known
mechanisms of
population control
Limits to Growth