ECOLOGY & ECOLOGY & FOODWEBSFOODWEBS

S7L4• Students will examine the dependence of organisms

on one another and their environments.– a. Demonstrate in a food web that matter is transferred

from one organism to another and can recycle between organisms and their environments.

– b. Explain in a food web that sunlight is the source of energy and that this energy moves from organism to organism.

– c. Recognize that changes in environmental conditions can affect the survival of both individuals and entire species.

– d. Categorize relationships between organisms that are competitive or mutually beneficial.

EQ’s to be answered in this unit:• How is life like a web?• Why is it necessary for everything in an

ecosystem to work together?• How do YOU fit into the larger world? • How does a change in temperature and/or

precipitation affect the living things in the environment?

• Why can’t there be a lone survivor?• What effect does the environment have on

organisms?• How does the environment affect us?

Chapter 20, Section 1 p.675• We’ve learned about biomes, and about the

characteristics of living things. Now we are gong to tie these things together by looking at…

p. 675 Habitats p. 675 Habitats • An environment that provides the things the

organism needs (food, water, shelter) to live, grow, and reproduce

• One area may contain many habitats

• Organisms live in different habitats because they have different requirements for survival.

p. 675 Factors p. 675 Factors • An organism interacts

with both the living and nonliving parts of its habitat.

• P.675 - Biotic factors: living parts of a habitat. Ex: grass, plants, hawks, ferrets, badgers, worms, fungi, bacteria

P.676 – Abiotic factors – Nonliving parts of an organism’s habitat.

• Water – Organisms require water to carry on life’s processes, and water makes up a large part of organisms’ bodies.

• Sunlight – Needed for photosynthesis; without it, few organisms can survive.

• Oxygen – Can be obtained from the air or from water, and is essential for life.

• Temperature – help determine the types of organisms that can live in an area.

• Soil - contains rock fragments, nutrients, air, water, & decaying remains; type of soil determines plants, and for many organisms, soil is used as a home.

p.677 Levels of Organization p.677 Levels of Organization • 1) Species – a group

of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce.

2) Populations

• all the members of one species in a particular area.

3) Communities

• all the different populations that live together in an area.

p. 678 4) Ecosystems

• The community of organisms that live in a particular area along with their nonliving surroundings.

BRAIN POP

http://www.brainpop.com/science/populationsandecosystems/ecosystems/zoom.weml

p.681 Studying Populations

Sometimes we need to know the size of a population of organism in a particular ecosystem. We use several different ways to determine the population:

p.682 Direct Observationp.682 Direct Observation• Counting all of the members in a

population

• Ex: Counting all the crabs in a tide pool

p.682 Indirect Observationp.682 Indirect Observation• Observing signs of organisms rather than the

organisms themselves

• Ex: Counting entrance holes to swallow nests

p.682 Samplingp.682 Sampling• Making an estimate (an approximation of a

number, based on reasonable assumptions).

• Ex: Counting number of organisms in a small sample area, then multiplying to find the number in a larger area

p.683 Mark-and-Recapture p.683 Mark-and-Recapture StudiesStudies

• Marking an organism, releasing it back into the wild, then returning at a later date to see how many organisms have marks, and how many do not.

• Ex: marking turtles, then coming back in 2 weeks and counting the number of marked turtles.

p. 684 Changes in p. 684 Changes in Population SizePopulation Size

• Populations can change in size when new members join the population or when members leave the population.

p.684 Births and Deathsp.684 Births and Deaths• The birth rate of a

population is the number of births in a population in a certain amount of time (ex: 600 per year)

• The death rate is the number of deaths in a population in a certain amount of time (ex: 400 per year)

p.684 The Population p.684 The Population StatementStatement

• If birth rate > death rate, population size increases.

• If birth rate < death rate, population size decreases

p.684 Immigration and p.684 Immigration and EmigrationEmigration

• The size of a population can also change when individuals move into or out of the population.

• Immigration means moving INTO a population

• Emigration means leaving a population

p.684 Graphing Changes in p.684 Graphing Changes in PopulationPopulation

• X axis shows time

• Y axis shows number of organisms

p.685 Population Densityp.685 Population Density• The number of individuals in an area of a

specific size

• population density = Number of individuals

Unit area

p.685-7 Limiting Factorsp.685-7 Limiting Factors• An environmental factor that causes

a population to decrease– Food and Water – often in limited

supply– Space - if it gets too crowded,

organisms don’t survive because their needs aren’t met.

– Weather – temperature and rainfall can limit population growth

• Carrying Capacity – the largest population that an area can support

BrainPop

• Population Growth

p.700 Changes in Communitiesp.700 Changes in Communities– Succession– the

series of predictable changes that occur in a community over time.

p.701 – Primary Successionp.701 – Primary Succession• The series of changes that

occur in an area where no soil or organisms exist.– Pioneer species– the first

species to populate the area, carried by wind or water. They help break up rocks, building soil. Ex: mosses, lichens

Primary SuccessionPrimary Succession

p.702 – Secondary Successionp.702 – Secondary Succession• The series of changes that occur in an

area where the ecosystem has been disturbed, but where soil and organisms still exist. Ex: fires, hurricanes, farming, logging, mining

ENERGY FLOW• Energy is transferred from one organism to another.

• Two methods of transfers

–Food Chain

–Energy Pyramid

FOOD CHAIN• Shows how energy passes from one

organism to another.

–A producer will ALWAYS be first. Producers make their own food through photosynthesis. (ex: plants, algae, some bacteria)

– CONSUMERS will be next:• A herbivore will be second.

–An organism that eats only plants (ex: rabbit, deer)

• A carnivore will be next.–An organism that eats other

animals (ex: hawk, wolf)• An omnivore can also be

next.–An organism that eats both

plants and animals (ex: bear, human)

• A scavenger can also be next.

–A carnivore that feeds on the bodies of dead organisms. (ex: catfish, vultures)

• A decomposer can also be next.

–An organism that breaks down wastes and dead organisms and returns the raw materials to the ecosystem (nature’s recyclers!). (ex: worms, mushrooms, bacteria)

EXAMPLE

GRASS RABBIT WOLF

Producer Herbivore Carnivore

Grass Grasshopper Frog Snake Hawk

• GRASS (is eaten by a) GRASSHOPPER (which is eaten by) a FROG (which is eaten by a) SNAKE (which is eaten by a) HAWK

Example of a Food Chain

ENERGY PYRAMID• Shows how much energy is at each level

of food chain• Pyramid Levels

– 1st level is carnivores • Larger animals• least energy

– 2nd level is carnivores– 3rd level is herbivores– 4th level is producers

• Plants• Most energy

ENERGY PYRAMID Carnivores Least Energy (Larger Animals)

Carnivores

Herbivores

Producers (Plants) Most Energy

Where Does Energy Comes From?

•SUN–Provides energy for life on Earth

BRAIN POP

http://www.brainpop.com/science/populationsresourcesandenvironment/foodchains/zoom.weml

p.694p.694How Living Things InteractHow Living Things Interact

• There are three major types of interactions among organisms: competition, predation, and symbiosis.

p.694 - Competitionp.694 - Competition• If two species occupy the

same niche, one of the species will eventually die off.

• Competition is the struggle between organisms to survive as they attempt to use the same limited resource.

p.695 Predationp.695 Predation• An interaction in which one organism

kills another for food

• Predator - The organism that does the killing.

• Prey – the organisms that is killed.

p.696 Adaptationsp.696 Adaptations• Predator Adaptations

– Help them catch and kill their prey. Ex: cheetah can run very fast.

• Prey Adaptations – Helps organisms avoid being killed. Ex: Skunk spray

p.697 Defense Strategiesp.697 Defense Strategies• Mimicry– Having a strong

resemblance to other predators

• Protective Coverings– Shield the organism from predators

• False Coloring– Scare potential predators away

• Warning Coloring– Bright colors warn predators not to eat them

• Camouflage – Hide from predators

SYMBIOSIS• Relationship between species

• Types:–Mutualism: both benefit

–Commensalism: one benefits, the other is not affected

–Parasitism: one benefits, the other is harmed

Mutualism – Bees & Flowers

Commensalism – Fish & anemones

Parasitism – Ticks

BrainPop Time Again!

• http://www.brainpop.com/science/livingsystems/symbiosis/

NICHE-Organism Survival• Every organism has a variety of adaptations

that are suited to its specific living conditions:– How does it find food and shelter?– How does it avoid danger?– How does it care for its young?– Does it have predators?– Can it cooperate with other animals?– Can it find prey (food)?

• A Niche is the role of an organism in its habitat, or how it makes its living.

Your Challenges: Show how you have mastered the

standards:a) Draw a food web containing at least 10 organisms that shows matter being transferred and recycled.

b) Show/Explain how the energy from sunlight moves from organism to organism. Include at least 5 organisms.

c) Explain how a change in an environmental condition would affect the survival of an individual organism, the population, the community, and the ecosystem

d) Describe 3 examples in your own life of relationships between organisms that are competitive and 3 that are mutually beneficial.

Let’s see if you can answer the EQ’s:• How is life like a web?• Why is it necessary for everything in an

ecosystem to work together?• How do YOU fit into the larger world? • How does a change in temperature and/or

precipitation affect the living things in the environment?

• Why can’t there be a lone survivor?• What effect does the environment have on

organisms?• How does the environment affect us?