Ecology
Everything Is Connected To
Everything Else
What is Ecology?
• Ecology is the study of the
relationships and interactions of
living things with one another and
with their environment.
What is the Environment?
• The environment includes all living and
nonliving things that surround an
organism.
Biotic vs Abiotic
• Biotic includes all
living things in the
environment.
– Examples: plants,
animals, insects,
protists, fungi,
bacteria, etc.
• Abiotic includes all
nonliving things in
the environment.
– Examples: light,
temperature, wind,
rocks, soil.
Is Water Biotic or Abiotic?
• Water itself is abiotic.
– Water contains many life forms
– Water is the one thing required by all
living things.
What is an Ecosystem?
• Scientists divide the world into
separate ecosystems.
– Example: a forest ecosystem
• An ecosystem is an area in which
living things and nonliving things
interact, exchanging energy and
materials.
What is a Community?
• A community is the living part of any
ecosystem - all the different
organisms that live together in that
area.
All the
living
things in
an area
form a
community
What is a Population?
• Each kind of living thing makes up a
population in the community.
• A population is a group of organisms
of the same species living together in
the same area.
Sea anemone population
Gopher mounds
What is a Habitat?
• A habitat is the specific place in which an
organism lives.
– A habitat provides food, shelter, and the other
resources an organism needs to survive.
– Different organisms live in different habitats
because they have different needs.
Ant population in its habitat
Egret population in its habitat with its community
Limiting factors
Energy Roles in the
Environment
• Organisms can be producers,
consumers or decomposers.
– These roles indicate how an organism
gets its energy and how it interacts
with other living things in the
community.
Energy Roles in the Environment
What is a Producer?
• A producer is the source of all the
food in an ecosystem.
– Producers are able to take a source of
energy, (such as sunlight), to turn raw
materials, (such as water and carbon
dioxide), into energy.
– Examples are green plants and certain
microorganisms.
What is a
Consumer?
• A consumer is an organism that feeds
directly or indirectly on producers.
– There are many kinds of consumers:
• Herbivores
• Carnivores
• Omnivores
• Scavengers
Herbivores
• Herbivores are consumers that feed
on plants.
– Examples are grasshoppers and rabbits
Herbivores
Herbivores
Carnivores
• Carnivores are consumers that feed
on other animals.
– Examples are spiders, snakes, wolves.
Carnivores
Carnivorous
Plants
Omnivores
• Omnivores are consumers that
feed on both plants and other
animals.
– Examples are humans, crows,
bears.
Omnivores
Scavengers
• Scavengers are animals that feed on
the bodies of dead animals.
• Examples are vultures, jackals,
hyenas.
More
Scavengers
What is a Decomposer?
• Decomposers are
organisms that break
down dead organisms
into simpler substances.
• Examples are mold,
mushrooms, bacteria.
Food Chains and Food Webs
• The food and energy links among
producers and consumers in an
ecosystem are represented by food
chains and food webs.
Food Chain
• A food chain represents a series of events
in which food and energy are transferred
from one organism in an ecosystem to
another.
– The first link in a food chain is always a
producer.
– The second link is a herbivore.
– The third link, and all the links after that, are
almost always carnivores.
– The “end” of a food chain is always connected
to the “beginning” by decomposers.
Food Web
• Since there are many organisms in an
ecosystem, and few that eat only one kind
of food, there must be more than one food
chain in an ecosystem.
• A food web consists of many overlapping
food chains.
– Food webs give the whole picture of the food
and energy relationships in an ecosystem.
What is a Niche?
• Every organism has a niche in life.
• A niche is the role an organism has in
an ecosystem.
– Niche is “what the organism does”
– An organisms niche includes: the place it
lives; the food it eats; the organisms
that feed on it, interact with it; the
amount of light, humidity and other
physical conditions it needs to survive.
Interaction Among Living
Things
• Ecosystems involve many interactions
between organisms.
• Each organism in a community has its
own unique role to play. This role, or
niche, is more than just the organisms
place in the food web.
Competition is Interaction
Competition vs Interaction
• Because the resources (food, water,
shelter, light etc.) of an ecosystem
are limited, it can not satisfy the
needs of all the organisms living in it.
• Competition is the interaction, or
struggle, of organisms against each
other to get the things they need to
survive.
Plant Competition
Animal
Competition
Predation is Interaction
• Predators are living things that
catch, kill, and eat other living things.
– Examples: cats, hawks, snakes.
• Prey are the organisms that are
eaten by predators.
– Examples: mice,
• Predation plays an important role in
shaping the structure of a community.
Some
Predators
Symbiosis is Interaction
• Symbiosis is the close relationship
between two organisms in which at
least one organism benefits.
• In symbiosis one organism lives near,
on, or even inside, another organism.
3 Categories of Symbiotic
Relationships
• Symbioses are placed into three
categories:
– Commensalism
– Mutualism
– Parasitism
Commensalism
• In commensalism, one of the
organisms benefits and the other is
not harmed by the relationship.
– Example: Sparrows and wrens set up
their nests below an osprey nest for
protection from enemies.
Examples of Commensalism
Mutualism
• In mutualism, both organisms benefit
from the relationship.
– Example: Ants “herd” aphids. Aphids get
fresh leaves for food and the ants get
the sugary secretion from the aphids.
– Example: Shrimp and gobi fish. Blind
shrimp gets “eyes”, gobi gets a home.
– Example: Microorganisms get a home and
help partner in some way (digestion).
Mutualism
• In mutualism, both organisms benefit
from the relationship.
– Example: Ants “herd” aphids. Aphids get
fresh leaves for food and the ants get
the sugary secretion from the aphids.
Examples of Mutualsim
– Example: Shrimp and gobi fish. Blind
shrimp gets “eyes”, gobi gets a home.
– Example: Microorganisms get a home and
help partner in some way (digestion).
Mutualism at Work
Parasitism
• In parasitism, one organism benefits
and the other organism is harmed.
– Example: ticks, fleas, mosquitos, leeches
all feed on another organism, a host,
that experiences some harm.
– Example: Disease-causing worms,
bacteria and viruses are internal
parasites.
Some Parasites
Parasite and Effects
Parasite vs Host
• In parasitism, a parasite usually lives
on or in a much larger organism and
feeds on it while it is still alive.
• The parasites unlucky partner is
called the host.
• Parasites do not usually kill their
host, but many do weaken it greatly.
Parasite and Host
Cycles in Nature Time
• Cycles in nature often
occur in a regular
rhythm, or time
pattern.
What is Rhythm?
• A rhythm is any pattern that occurs
over and over again.
• Many biological rhythms are often in
harmony with natural cycles.
– Daily rhythms
– Lunar rhythms
– Annual rhythms
Daily Rhythms
• Diurnal organisms
are those that are
active during the
day.
• Nocturnal
organisms are
those that are
active during the
night.
Lunar Rhythms
• Lunar rhythms are rhythms that are
controlled by the moon, such as the
rise and fall of the tides.
What are Biological Clocks?
• Biological clocks are internal timers that
may be responsible for keeping track of
many different cycles of time.
Why Have Biological Clocks?
• Biological clocks help organisms survive.
• Biological clocks help living things stay
in step with rhythmic cycles of change in
their environment.
– When the time is right, biological clocks
tell organisms to change their appearance,
behavior, or body functions in some way.
Cycles in Nature –
Annual Rhythms
• Many natural rhythms are closely
associated with the seasons of the
year.
• Annual rhythms are events that
occur once a year.
– There are many examples of annual
rhythms such as migration, hibernation
and estivation.
Cycles in Nature - Migration
• Migrations are annual rhythms in
which organisms travel from the
place where they breed to the
place where they feed.
Why Migrate?
– Organisms migrate to find more
beneficial environments as seasonal
changes make their old environment less
habitable.
– Examples: Geese, turtles, whales, salmon
Migration Patterns
Cycles in Nature - Hibernation
• Some organisms avoid unfavorable
seasonal changes by “sleeping”
through the bad periods of the year.
• During this “sleep” the body functions
of the animal slows down.
• This enables animals to wait out the
bad periods of the year in a sheltered
hiding place.
What is Hibernation?
• Hibernation is the winter resting,
“sleeping”, state for organisms avoiding
the cold, harsh winter months.
– Examples: bears, toads.
Hibernating Boar
What is Estivation
• Estivation is the summer resting,
“sleeping” state for organisms avoiding
the hot, dry, harsh summer months.
– Example: African lungfish buries itself in
the mud at the bottom of the lake before
it dries out. These fish can survive for
years in their shell of dried mud.
Estivation
Cycles of Matter
• Matter can not be created or destroyed.
• Matter, in the form of chemicals, flows
in cycles from the nonliving part of the
environment to living things and back
again.
4 Important Matter Cycles
• Hydrologic
(Water) Cycle
• Carbon Cycle
• Oxygen Cycle
• Nitrogen Cycle
The Water Cycle
Water Cycle Terms
• Radiation is the suns energy (heating water).
• Evaporation is water (liquid) changing to water
vapor (gas). Evaporation requires energy.
• Condensation is water vapor (gas) changing to
water (liquid). Condensation releases energy.
• Precipitation is any form of water falling from
the sky.
• Infiltration/Percolation is water filtering into
the ground.
• Runoff is water that flows on top of the ground.
• Perspiration is water that comes out of animals in
the form of sweat. Respiration is from breathing.
• Transpiration is water that comes out of plants.
The Oxygen and Carbon Cycles
• Carbon dioxide is used by producers
such as green plants.
• Oxygen is released by producers such
as green plants.
• Oxygen is used by air-breathing
organisms.
• Carbon dioxide is released by airbreathing organisms.
Two Carbon Cycles
The Nitrogen Cycle
• All living things need nitrogen but most organisms can not get
enough from the air.
• Nitrogen fixation by bacteria use free nitrogen in the air to make
nitrogen compounds called nitrates.
• Plants use the nitrates to make compounds called proteins.
• Other organisms that can not use nitrates directly use the
proteins containing nitrogen.
• Decomposers, such as bacteria, break down the complex nitrogen
compounds in dead organisms and animal waste, returning simple
nitrogen to the soil.
• Nitrogen can go back and forth between plants and soil many
times.
• Eventually bacteria break down the nitrogen compounds into free
nitrogen which is released into the air.
Nitrogen
Cycle
Cycles of Change
• Ecological succession is the process
in which the community in a particular
location is gradually replaced by
another community.
• Succession usually takes a long time.
Primary and Secondary
Succession
• Primary succession is
the establishment and
development of
communities in newly
formed areas.
– Such as cooled lava,
rocky surfaces, and
sandy areas.
• Secondary succession
is succession that
occurs in disturbed
areas.
– Such as abandoned
farmland, vacant lots,
and cleared areas.
Stages of Ecological Succession
Ecological
Succession
When Does Succession End?
• Left alone, over time, a community may
consist of a group of species that are not
replaced by new species.
• This stable collection of plants, animals and
other organisms is known as a climax
community.
– Examples are redwood trees in Northern
California, black pines in the pine barrens, oak
and hickory trees in the North Eastern U.S.
Climax Communities
Biogeography
• Biogeography is the study of where plants
and animals live throughout the world.
Dispersal is the movement of
living things from one place to
another.
Barriers to Dispersal
• Natural barriers such
as water, deep valleys
or mountains can
prevent dispersal.
• Ecological barriers
such as habitats that
do not meet the
organisms needs also
prevent dispersal.
– Example is the opossums
move north.
• Objects built by
man can also be
barriers to
dispersal.
– Examples are
dams blocking
salmon, highways,
fences.
Natural Barriers
Man-made Barrier
Biomes of the World
• Areas of the world are characterized
by their climate and the organisms
living there.
• Biomes are environments that are
grouped by similarities in climate and
ecological communities.
6 Major Land Biomes
• Scientists have identified 6 major
land biomes of the world:
–
–
–
–
–
–
Tundras
Coniferous forests
Deciduous forests
Tropical rain forests
Grasslands
Deserts
Tundra Biomes
• The climate of a tundra is very cold
and dry. (Like a cold desert)
– Temperatures rarely go above freezing.
– Rainfall is less than 25 cm. per year
• The soil there that is permanently
frozen is called permafrost.
• Life forms are lichens, dwarf willows,
caribou, musk oxen, lemmings.
Tundras
Coniferous Forest Biomes
• The climate here is cold but the soil thaws
completely in spring forming swampy areas.
• Coniferous forests are made up of trees
called conifers that survive well in the
poor soil of these areas.
– Conifers, also known as evergreens, produce
their seeds in cones.
• Animals include moose, birds, beavers, lynx,
weasels, and squirrels.
Coniferous Forests
Deciduous Forest Biomes
• The climate here is warmer and there is at
least 75 cm of rain per year.
• Deciduous trees, such as oaks, maples,
hickories and beeches, shed their leaves in
autumn making the soil richer.
• Animal life includes insects, spiders,
worms, snails, frogs, raccoons, deer, birds,
grouse, snakes, salamanders.
Deciduous Forests
Tropical Rain Forest Biomes
• The climate here is like summer all year
round and it rains almost every day (at least
200 cm. of rain per year).
• Plant life is more varied than any other
biome due to good soil, lots of water, and
year-round growing conditions.
– A canopy, or green roof where tops of trees
meet, keeps the ground cool and dimly lit.
• Animal life is also varied (insects, birds,
snakes, monkeys, wild cats) due to abundant
food supplies.
Tropical Rain Forest Biomes
• Most of the undiscovered species of
plants, animals and insects, exist in
tropical rain forest biomes.
Rain Forests
Grassland Biomes
• The climate here is warm with low rainfall
(between 25 and 75 cm. yearly).
• Africa has the largest grasslands in the
world.
• Grasses are the main group of plants
accompanied by few, thorny trees called
acacias. Wildfires often prevent tree
growth.
• Animal life is largely herbivores such as
zebra, antelope, mice, rats, also snakes,
lions, cheetahs, elephants, hawks, eagles.
Grasslands
Desert Biomes
• A desert biome is very dry (receives less
than 25 cm. of rain per year) but can be
either hot or cold.
– Sahara Desert is hot; Gobi desert is cold.
• Plant life, cactus, aloe, palm trees, survive
on little water.
• Animal life, such as lizards, rodents,
camels, must survive on little water.
Deserts
Water Biomes
• The two major water biomes are:
– Marine biomes
– Freshwater biomes
Marine Biomes
• The marine biome, or ocean biome, covers
about 70% of the earth.
• Oceans are divided into different zones based
on sunlight, temperature, pressure, and
currents with different organisms in each.
• Organisms living here have adapted to be able
to survive in salt water.
• Phytoplankton are microscopic plants that live
near the surface. Almost all animals in the
oceans depend directly or indirectly on these
plants.
Freshwater Biomes
• The freshwater biome includes both still
water (ponds and lakes) and running water
(rivers and streams).
• There are factors that affect the life in
freshwater biomes:
–
–
–
–
–
Temperature
Sunlight
Amount of oxygen
Food available
Speed of movement
Fresh Water Biome
Estuaries
• An estuary is a boundary between a
freshwater biome and a marine biome.
• Estuaries are extremely fertile areas.
– Since estuaries are shallow, sunlight reaches all
levels so marsh grasses, algae and other plants
live there and provide food for a variety of
fishes, crabs, oysters and shrimp.
• Estuaries are important as “nurseries” for
many different types of young fishes.
Wildlife Conservation
Earth’s Natural Resources
Energy Resources
Earth’s Nonliving Resources
Pollution
Conserving Earth’s Resources