Download Ecosystems and Their Interactions

Ecosystems and Their
Interactions
Environmental & Ecology PA
State Standard
4.6.12.ABC
Ecosystems are a fine balance.

An introduction of
one species can
interrupt an entire
ecosystem.
 In 1988, human
actions accidentally
intervened in the
Great Lakes with the
introduction of the
zebra mussel, an
aquatic shelled
animal smaller than
an adult thumb.
Zebra mussel

They came in
or on a boat
from Europe.
(Most likely in
the ballast
water of a
cargo ship)
Zebra mussel waterway invasion
•Zebra
mussels have
spread
largely due to
boaters
Pros & Cons of zebra mussels


Pros

Cleanse water of some
pollutants
 Lakes are clearer
allowing light to
penetrate deeper for
more aquatic plant
growth.
Cons
 Grow in clumps and
clog intake pipes for
power plants and
municipal water plants.
 Interfere with feeding,
growth, and
reproduction of native
mussels
 Eat all the
phytoplankton &
zooplankton that are
the foundation of
aquatic food chains


Ecologists learned that a
small change (one
organisms) can have a
large impact on the entire
ecosystem, even if it is
accidental.
THINK ABOUT THAT
THE NEXT TIME YOU
WANT TO RELEASE
YOUR UNWANTED PET
INTO THE
ENVIRONMENT.
Biosphere

A layer of
soil, water,
and air that
sustains life.
Ecosystem

Consist of a group
of living
organisms that
interact with one
another and the
nonliving physical
environment as
one unit
Terrestrial (land) ecosystems

Forest

Desert

Grasslands

These vary depending climate and soil in the
area, as well as the type of organisms in it.
Forest Ecosystems


Common in PA- more than half the state
Oak-hickory most common in PA 47%


Largest & most important plants in this
ecosystem
Northern hardwoods

38% of state
 Birch, sugar, maple, beech, & black cherry
Aquatic Ecosystems

Freshwater ecosystems


Ponds, lakes, rivers, streams, & wetlands
Marine ecosystems

Estuaries, coastal marshes, coral reefs, and
the open ocean
Hierarchy of ecosystems
1.
2.
3.
4.
5.
Organism: any form of life
Species: a group of organisms alike in several
ways that can breed
Population: a group of individuals of the same
species in a given area
Community: populations of living organisms
that interact with one another in an ecosystem
Ecosystem: living & nonliving interacting
Examples
Habitat

The place where a particular species lives
and from which it obtains what it needs for
survival

Can be as large as the Atlantic Ocean or
as small as a rotting log in a hardwood
forest in northwestern PA
Biotic Factors in an ecosystem

All living things

Ex: plants, animals, fungi, & microorganisms
 Can you list some in a PA forest???

These biotic factors interact with one
another (predator-prey relationships)
Abiotic factors in an ecosystem

Nonliving physical and chemical parts of an
ecosystem
 Although they are nonliving they still greatly
influence the biotic factors
 Can you think of some abiotic factors on
land???? How about water?????

How are they interdependent on one another?
Each species survives best in a
specific range of environmental
conditions

Remember the macroinvertebrate study
 What types of water did trout prefer?
Caddisflies? leeches?

In PA beech trees survive best in shade whereas
black cherry prefer open sunny locations
 In closed canopies, young black cherries cannot
survive
Human interaction can disrupt
ecosystems

Constructing a dam can change the conditions of
the stream downstream




They block nutrient rich sediment from going
downstream because they back up behind the dam
wall.
Many plants & animals downstream suffer
Can block fish from heading upstream to
reproduce(salmon)
Alter the temperatures by raising and lowering the
water level
Human interaction can disrupt
ecosystems

Concentration of toxic substances in air,
water, and soil

Electric Power plants

Acid rain
Matter & Energy in an ecosystem

Food chain: the transfer of energy from
one organism to another

As one organism eats another organism, that
energy is transferred
Forest Food Chain
Food Web: A network that shows
many connected food chains
Food chain vs Food web

A food chain is a linear depiction while a food
web shows the interconnectedness between all
the organisms in the food chains

Regardless, all of the energy begins with the sun

Plants  photosynthesis  glucose
Producers

Uses elements from
the environment to
make its own food

Convert solar energy
to chemical energy
and store it in their
cells
Consumer

An organism gets its
energy and nutrients
by feeding on other
organisms
Different consumers: Herbivore,
carnivore, omnivore

Primary consumer: feed on plants(herbivores)
 Secondary consumer: feeds on primary
consumers (carnivore/omnivore)
 Tertiary consumer: feeds on primary & secondary
consumers
 List some examples of each
Scavengers & Decomposers

Scavenger: feeds on dead organisms

Decomposers: usually a type of bacteria or
fungus that breaks down dead organisms and
wastes

These are both important because they
breakdown wastes in the environment
Trophic levels

Contains all organisms in a feeding level
that are the same number of steps away
from the sun

As you move up from one trophic level to
another in an ecosystem, there is a 90%
loss of energy(as heat)
Trophic levels & energy



That means only 10% of energy is passed
from one trophic level to the next.
Food webs usually have no more than 4-5
trophic levels
There is too little energy left to support
many higher organism (energy pyramid)
Soil- a major part of an ecosystem

Soil is a precious renewable resource because it
takes so many years to produce.

Soils vary from place to place depending on the
parent material from which it is derived.

Each layer is called a soil horizon
Soil erosion



Depends on climate-precipitation
Human impact-logging, farming
These factors increase the rate of erosion,
supporting fewer producers and ultimately
fewer consumers
Sediment

Sedimentation- areas
where large deposit of
sediment accumulate


These are fertile area
because they carry a
lot of nutrients.
These can form deltas
Carrying capacity of an Ecosystem

The number of
individuals of a
species that it can
support
Carrying capacity

Populations cannot grow indefinitely,
individuals are born, migrate and or die

There are many factors which affect these
processes.
Example

Adequate rainfall, good weather, leads to
high production of acorns, which leads to
more turkeys surviving winter, therefore
increased reproduction of turkeys.

Therefore, weather, habitat quality, species
survival, and reproduction all affect
population growth.
Limiting factors

Factors that limit the growth of a population

This is the most important factor because it
gives an ecosystem a finite capacity for
growth
Exponential growth

A line graph that
shows exponential
growth forms a Jshaped curve

This cannot sustain
itself indefinitely
Carrying capacity

Population reaches its
carrying capacity
forming a S-shaped
curve
 Grows slowly at first
then increases more
& more quickly
depending on limiting
factors
Overshooting the carrying capacity

Deer population explodes
 Eats tons of young shrubs and trees which
deprives many other forest organisms that rely
on it

Some pops will die back, some will migrate to
another area.
 Many other species will die back before the deer
would
Habitat & niches

Habitat is an area where an organism lives


A forest ecosystem may include tree branches, rotting
logs, soil, holes in the tree trunks, or spaces under a
rock
Niche is the role an organism plays within an
ecosystem


Includes the food an organism eats and how it obtains
its food
Ex predator/prey diurnal/nocturnal
Niche

No two species can occupy the same niche in
one ecosystem.

If they did for a short time, competition for food,
water, and space would cause one species to
eliminate the other.
Darwin’s Finches
 Modify environment-plant send out toxins to keep
other plants away
 Beavers build dams and restrict the flow of water

Eastern wood rat

Knowing an organisms
niche helps protect it

Eastern wood rat is
threatened in PA

Ecologists are studying its
niche to try to help
preserve the species
Exotic species

Exotic species often
occupy the same
niche as native
species but are better
able to compete with
them because the
exotic species have
no natural enemies in
the new ecosystem
Homeostasis

The natural stability in an ecosystem

It helps an ecosystem resist transformation and
helps it recover when stresses are so great that
they cause serious problems

Organisms in the ecosystem have the ability to
resist change, but it is a delicate balance
Ecosystems can bounce back

Hurricanes and fires occur in areas and
devastate them
 However, organisms have a way of bouncing
back but it may change that particular
ecosystem.

But some changes are too drastic and it may not
be able to repair itself.
Biomes

A geographical region of Earth that is
inhabited by a community of distinct types
of plant and associated animal species

Defined by climate (annual temps and
precipitation), soils, latitude & altitude
Types of biomes





Land
Grassland
Desert
Highland
Ice cap
Land biomes/forests:
Tropical rain forest

Central SA, Africa, Southeast Asia & N.Australia
 Largest in South America- Amazon
 Heavy rainfall, lush vegetation growing in distinct
layers

Lowest layer must adapt to limited sun
Poor soil-trees’ roots grow laterally to absorb
nutrients from leaf litter
 Greatest species diversity on Earth-80% of
species but it covers only 2% of land surface

Land biomes/forests:
Tropical Deciduous/Scrub forest



A deciduous tree is a tree that survives
during a cold or dry season by dropping its
leaves.
TD is similar to TR but less rain and less
intensity, trees are less lush and dense
than TR
Scrub forests have small deciduous and
evergreen trees.
Land biomes/forests:
Temperate Deciduous


Moist areas with long, warm summers and cold
winters (precipitation all year)
PA is in this biome
 Dominate trees: oaks, hickories, maples,
beeches, and sycamores
 Animals: bear, deer, squirrels, rabbits, raccoons
Land Biomes/Forests:
Temperate



Mid-latitude coastal areas with mild
winters/ heavy rainfall
Coniferous forest(cone bearing trees)
dominate (pines, firs, spruces)
Oregon, Washington, Canada
Land Biomes/Forests:
Boreal

Taiga- northern most forest
 Evergreen conifers dominate


Thin needles of evergreens help tree to survive in the
cold weather
Long, cold, dry winters
 Little diversity, poor soil
Grassland Biomes

Less rain than forests but more than desert
biomes

Periodic drought & seasonal fires help
maintain natural grasslands from shrubs
taking over
Grassland biome:
Savanna




Grasslands of the tropic/subtropic
Warm all year, short wet season, long dry
season
Largest in southern Africa, central South
America, Australia
Giraffes have specific niche to eat tops of
trees, zebras grass on ground
Grassland Biome:
Temperate Grassland

Most interior of North America
 Tall-grass prairie of the Midwest & short-grass
areas of western Plains

Winters very cold, summers hot and dry
 Fertile soil due to the upper portion of the grass
dies off each year
 Corn Belt/ wheat
 Prairie dogs, jackrabbits, squirrels, coyotes,
wolves, bobcats
Grassland Biome:
Tundra





AKA: Polar grasslands
Treeless plains, cold all year, little
precipitation(snow)
Plants are well adapted to the cold, waxy
Mosses, lichens, short shrubs
Hares, squirrels, and lemmings(thick fur)
Desert

An area that typically gets less than 10 inches of
rain each year ( can be hot or cold)
 Tropical: high temps all year low precipitation ex
southern Sahara


Sand dunes rock formations
Temperate:hot summers/cool winters, more
annual rain ex:Mohave
 Cold:cold winters/hot summers ex: Gobi desert of
China & Antarctica
Desert Plants

Special adaptations to extreme
environment

Store water
 Succulents have thick, wax coated leaves that
cut down on moisture loss
 Extensive root systems

Animals burrow underground to escape the
heat
Chaparral

Mild, rainy winters and hot, dry summers

Southern California, around the Mediterranean
Sea

Evergreens with hard leathery leaves
 Prone to wildfires in late summer and fall

Many seeds need fires to open & sprout seeds
Highland: Mountains

Temperature drops with elevation
Depending on windward, precipitation
changes

Eastern side drier

Ice caps

Polar areas that are always cold & where
snow builds up from year to year into
enormous ice sheets that cover the land
surface

Antarctica and the interior of Greenland
Aquatic Biomes:
Freshwater

Streams, rivers, lakes, ponds, and
wetlands that occur inland


Less conc. of salt
Pa has all of these

41% of the world’s fish species live in them
Aquatic biome:
Marine



Saltwater, the oceans, cover most of the
Earth
Estuaries & coastal salt marshes- breeding
ground for many aquatic animals &
waterfowl
Pa does not have an ocean coastline, but
the southeastern corner borders Delaware
near the Delaware Bay
Ecosystem Review
Hierarchy of ecosystems
1.
2.
3.
4.
5.
Organism: any form of life
Species: a group of organisms alike in several
ways that can breed
Population: a group of individuals of the same
species in a given area
Community: populations of living organisms
that interact with one another in an ecosystem
Ecosystem: living & nonliving interacting
Habitat

The place where a particular species lives
and from which it obtains what it needs for
survival
Biotic Factors in an ecosystem

All living things


Ex: plants, animals, fungi, & microorganisms
These biotic factors interact with one
another (predator-prey relationships)
Abiotic factors in an ecosystem


Nonliving physical and chemical parts of
an ecosystem
Although they are nonliving they still
greatly influence the biotic factors
Producers

Uses elements from
the environment to
make its own food

Convert solar energy
to chemical energy
and store it in their
cells
Consumer

An organism gets its
energy and nutrients
by feeding on other
organisms
Different consumers: Herbivore,
carnivore, omnivore



Primary consumer: feed on
plants(herbivores)
Secondary consumer: feeds on primary
consumers (carnivore/omnivore)
Tertiary consumer: feeds on primary &
secondary consumers
Scavengers & Decomposers

Scavenger: feeds on dead organisms

Decomposers: usually a type of bacteria or
fungus that breaks down dead organisms and
wastes

These are both important because they
breakdown wastes in the environment
Trophic levels

Contains all organisms in a feeding level
that are the same number of steps away
from the sun

As you move up from one trophic level to
another in an ecosystem, there is a 90%
loss of energy(as heat)
Exponential growth

A line graph that
shows exponential
growth forms a Jshaped curve

This cannot sustain
itself indefinitely
Carrying capacity

Population reaches its
carrying capacity
forming a S-shaped
curve
 Grows slowly at first
then increases more
& more quickly
depending on limiting
factors
Habitat & niches

Habitat is an area where an organism lives


A forest ecosystem may include tree branches, rotting
logs, soil, holes in the tree trunks, or spaces under a
rock
Niche is the role an organism plays within an
ecosystem


Includes the food an organism eats and how it obtains
its food
Ex predator/prey diurnal/nocturnal