Description
A. Plants and animals, including humans, interact with
and depend upon each other and their environment to
satisfy their basic needs.
B. Both human activities and natural events can have
major impacts on the environment.
C. Energy flows from the sun through producers to
consumers.
 SC.7.L.17.1
 Explain and illustrate the roles of and relationships among
producers, consumers, and decomposers in the process of
energy transfer in a food web.
 SC.7.L.17.2
 Compare and contrast the relationships among organisms
such as mutualism, predation, parasitism, competition,
and commensalism.
 SC.7.L.17.3
 Describe and investigate various limiting factors in the local
ecosystem and their impact on native populations,
including food, shelter, water, space, disease, parasitism,
predation, and nesting sites.
Ecosystems include…
 Organisms that live in a particular area
 physical surroundings
 Organisms interacting with each other
 by sharing and competing for resources
 Organisms interacting with their physical environment
Bottom Line: Ecosystems can be found
wherever organisms are living
and interacting!
ECOLOGICAL
RELATIONSHIPS
 Habitat – An organism’s
habitat is where it lives in an
ecosystem.
 Niche – a certain role that
each population has in its
environment (ex. Both
eagles and owls feed on
mice, but owls hunt at night
while eagles hunt during the
day.)
 In a healthy ecosystem,
populations are
interdependent – they
depend on each other for
survival!
The environment
determines the type of
ecosystem that will
develop in an area.
Factors include:
 Soil conditions
 Temperature
 Rainfall
 Plant Life
 Amount of Food
KNOWLEDGE CHECK
1.
A single organism in an environment is called an _______.
2.
In a healthy ecosystem, each population contributes to the
______ of the other populations.
3.
The amount of food is a ________ that affects population
density.
4.
A ______ is a place where a population lives in an ecosystem.
5.
A population has a role or _______ in its environment.
6.
The sizes of animal populations are determined by the kinds
and numbers of __________ in an ecosystem.
Word Bank:
niche
plants
individual
habitat
limiting factor
survival
KNOWLEDGE CHECK
1.
A single organism in an environment is called an
individual.
2.
In a healthy ecosystem, each population contributes
to the survival of the other populations.
3.
The amount of food is a limiting factor that affects
population density.
4.
A habitat is a place where a population lives in an
ecosystem.
5.
A population has a role or niche in its environment.
6.
The sizes of animal populations are determined by
the kinds and numbers of plants in an ecosystem.
How Energy Is Transferred in
an Ecosystem
 The sun provides the
energy for almost
every ecosystem on
Earth. Producers
use the sunlight to
make food they need
from carbon dioxide
and water (ex.
plants).
 Consumers – all the
animals in a
community (ex. all
the animals that are
eating)
Food Chains
 Food chains show how consumers,
 The chain continues with more
producers, and decomposers are related
levels of carnivores that eat one
for survival.
another.
 Begins with producers (usually plants)
 Next level contains herbivores – animals
that eat only plants.
 They are eaten by the next level of
 The chain ends with decomposers
such as bacteria which breaks
down the tissues of dead
organisms. Whatever is left over
returns to the soil and helps start
animals on the food chain – the carnivores
the cycle over again by giving
(meat eaters).
nutrients to the producers!
EXAMPLES of
PRODUCERS
AND
CONSUMERS
Both land
and marine
Lions
Predator
Insects, Birds, Hyenas, Worms
Secondary and Tertiary consumers
Carnivores, Omnivores
Zebras and Gazelles
Primary Consumers
Herbivores
GRASSES
(producers)
Energy from the grass is both used and
stored by the animals who eat the grass
directly and by those who eat those
animals.
1. Where are ecosystems found?
2. What are the three links in the
food chain?
3. Give an example of each link in
the food chain.
1. Where are ecosystems found?
Ecosystems can be found wherever organisms are
living and interacting!
2. What are the three links in the food
chain?
Producer, Consumer, Decomposer
3. Give an example of each link in the
food chain.
Producer = Plants
Consumer = Bear
Decomposer = Bacterial
ECOLOGICAL
RELATIONSHIPS
COMPETITION
 Resources in ecosystems
may be limiting; therefore,
competition for these
resources may occur.
 Resources under competition
may include food, water,
sunlight, or shelter
 The more needs that are in
common, the more intense
the competition.
 If an organism
competes successfully
for resources, it is more
likely to survive and
reproduce!
 This is why there are
PREDATORS and
PREY!
ECOLOGICAL
RELATIONSHIPS
Symbiosis: A close relationship
between organisms of different species
4 types of symbiosis:
Commensalism
Mutualism
Parasitism
Mimicry
ECOLOGICAL
RELATIONSHIPS
Parasitic Isopod on fish
 Commensalism- A
relationship in
which one organism
benefits and the
other is not affected Imperial shrimp
hitching a ride on
a sea-cucumber
 Mutualism – A
relationship in
which both
organisms benefit
from each other
Clownfish in
host sea
anemone
 Parasitism – A
relationship in which
one organism benefits
and the other is harmed
 Mimicry – When species
mimic colors, patterns,
or behavior of another
species in order to get
closer to unsuspecting
prey or to gain
protection by imitating
a predator
Two of these are
Bumblebees(with stingers) and
two are Robber Flies (which
also make a sound similar to a
bee).
Living on the Serengeti Plain are
herds of lions, zebras, hyenas,
birds, ticks, and fleas. Using this
information, list the ecological
relationships in terms of
competition and symbiosis.
 Living on the Serengeti Plain are herds of lions,
zebras, hyenas, birds, ticks, and fleas. Using
this information, list the ecological relationships
in terms of competition and symbiosis.
SYMBIOSIS
COMPETITION
Mutualism: Zebra and Bird
Zebra and Hyena
Commensalism: Lion and Hyena
(Both eat grass).
Parasitism: Flea and Lion
LIMITING FACTORS
 Limiting factors are
things that prevent a
population from
growing any larger.
 If any of the limiting
factors change, animal
and plant populations
change, too.
 Limiting factors
include:
 Water
 Food
 Shelter
 Space
 Predation
 Disease
Limiting Factors
FOOD/WATER
 If there is limited food for
a population, the species
will not survive.
 Lack of food or water can
create competition among
populations and species.
 Without proper nutrition,
species cannot thrive and
survive.
SHELTER/SPACE
 SHELTER: is a prime
factor. Without proper
shelter, predators can
diminish a population
quickly.
 SPACE: Humans can
impact animal and plant
populations. When
humans develop land for
houses and buildings,
they cut down trees and
change animal and plant
habitats.
Limiting Factors
 Limiting factors are very closely tied to carrying
capacity. Many kinds of animals can increase in
numbers very quickly and may temporarily exceed the
carrying capacity of their habitat.
 This results in stress, starvation, disease, predation,
and parasites, poor reproductive success and damage to
the habitat.
 For example, multiplying muskrats can very quickly eat
all the vegetation in a marsh. With the vegetation gone,
food becomes the limiting factor, and the muskrats may
starve or move to another area. The marsh now has a
reduced carrying capacity for muskrats until the
vegetation grows back again.
http://homestudy.ihea.com/wildlife
/09limits.htm
Living on the Serengeti Plain are
herds of lions, zebras, hyenas,
birds, ticks, and fleas. Using this
information, what is/are the
limiting factor(s) of this
ecosystem?
Living on the Serengeti Plain are
herds of lions, zebras, hyenas,
birds, ticks, and fleas. Using this
information, what is/are the
limiting factor(s) of this ecosystem?
Grass and water. Without these,
the bottom of the food pyramid
would disappear, creating a chain
reaction to the top.