1. ECOLOGY & FOODWEBS

2. UNIT 2: 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.

3. 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?

4. Habitats
An environment that provides the things that an organism needs to live, grow, and reproduce.
Organism
A single living thing (plant, animal, fungus, protist, bacteria)
Needs food, water, & shelter

5. Organisms Interact With Both:
Biotic Factors
Any plant or animal; living things
Abiotic Factors
Objects that do not have living characteristics; non- living things
Example: water, sunlight, oxygen, temperature, soil

6. Population vs. Community
Species
A group of organisms that are physically similar and can mate with each other
Example: bear
Population
All members of one species in a particular area
Example: a group of deer in a forest
Community
All different populations that live together in an area and are close enough to interact with each other
Example: birds, bears, snakes, all living in the forest

7. ECOSYSTEM LEVELS of ORGANIZATION: Species: Prairie Dog
The community of organisms that live in a particular area, along with their nonliving surroundings, make up an ecosystem.
Example: Prairie, mountain streams, deep oceans, and forests
LEVELS of ORGANIZATION:
Species: Prairie Dog
Population: Prairie Dog Town
Community: All the living things that interact on the prairie (grass, prairie dogs, skunks)
Ecosystem: All the living & nonliving things that interact on a prairie (grass, owls, prairie dogs, snakes, sun, water, soil)

8. Where Does Energy Comes From?
SUN
Provides energy for life on Earth

9. 2 Ways To Obtain Energy Producers Consumers
Organism that can make its own food using the Sun
Example: Plants
Consumers
Organism that gets energy by feeding on other organisms
Example: Animals

10. How Do They Get Energy?
Here is how energy passes from one organism to another.
PRODUCERS will ALWAYS be first. Producers make their own food.
CONSUMERS will be next:
herbivore
An organism that eats only plants (ex: rabbit, deer)
carnivore
An organism that eats other animals (ex: hawk, wolf)
omnivore
An organism that eats both plants and animals (ex: bear, human)

11. How Do They Get Energy?
Here is how energy passes from one organism to another.
scavenger
A carnivore that feeds on the bodies of dead organisms (ex: vultures)
decomposer
An organism that breaks down chemicals from wastes and dead organisms, and returns important materials to the soil and water. (ex. fungi & bacteria)

12. Interactions of Living Things
There are three major types of interactions among organisms:
Predation
An interaction in which one organism kills another for food
Competition
The struggle between organisms to survive as they attempt to use the same limited resources
Symbiosis
A close relationship between two species that benefits at least one of the species

13. Interactions of Living Things
An interaction in which one organism kills another for food is called predation.
A tiger shark lurks below the surface of the clear blue water, looking for shadows of albatross chicks floating above. The shark spots a chick and silently swims closer. Suddenly, the shark bursts through the water and seizes the albatross with one snap of its powerful jaw. This interaction between two organisms has an unfortunate ending for the albatross.
predator
The organism that does the killing
prey
The organism that is killed

14. Interactions of Living Things
The struggle between organisms to survive as they attempt to use the same limited resources is called competition.
In any ecosystem, there is a limited amount of food, water, and shelter.
Organisms that survive have adaptations that enable them to reduce competition.
Adaptations are behaviors or physical characteristics that allow organisms to be successful in their environment.

15. NICHE-Organism Survival
A Niche is the role of an organism in its habitat, or how it makes its living.
Consists of a variety of adaptations that are suited to the organisms 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)?

16. Interactions of Living Things
A close relationship between two species that benefits at least one of the species is called symbiosis.
There are three types of symbiotic relationships:
Mutualism: A relationship in which BOTH species benefit.
Commensalism: A relationship in which ONE species benefits and the other species is neither helped nor harmed.
Parasitism: A relationship in which one organism lives ON or IN another organism and HARMING it.

17. Interactions of Living Things
A close relationship between two species that benefits at least one of the species is called symbiosis.
Mutualism: A relationship in which BOTH species benefit.
Example:
+ birds that ride on a rhino’s back
they eat bugs & ticks on the rhino’s back
they get food and the rhino gets clean

18. Interactions of Living Things
A close relationship between two species that benefits at least one of the species is called symbiosis.
Commensalism: A relationship in which ONE species benefits and the other species is neither helped nor harmed.
Example:
+ birds that build nests in tress
the bird now has shelter but the tree is not helped or harmed by this interaction.

19. Interactions of Living Things
A close relationship between two species that benefits at least one of the species is called symbiosis.
Parasitism: A relationship in which one organism lives ON or IN another organism and HARMING it.
A parasite is the organism that lives on or in another organism and is benefitting.
A host is the organism that the parasite is living on or in.
Example: a tick living on a dog

20. Mutualism – Bees & Flowers
Parasitism – Ticks
Mutualism – Bees & Flowers
Commensalism – Fish & anemones

21. ENERGY FLOW Energy is transferred from one organism to another.
The movement of energy through an ecosystem can be shown in diagrams.
Two diagrams of energy transfers
Food Chain/Food Web
Energy Pyramid

22. Tree  Carpenter Ant  Woodpecker
Food Chains
A food chain is a series of events in which one organism eats another and obtains energy.
The first organism in a food chain is ALWAYS a producer!
The second organism feeds on the producer and is called a first-level consumer.
Next, a second-level consumer eats the first-level consumer.
Finally, a third-level consumer may eat a second-level consumer.
TREE (a PRODUCER is eaten by a) CARPENTER ANT (a FIRST-LEVEL CONSUMER which is eaten by) a WOODPECKER (a SECOND-LEVEL CONSUMER)
Tree  Carpenter Ant  Woodpecker

23. EXAMPLE
GRASS RABBIT WOLF Producer Herbivore Carnivore

24. Food Webs
A food chain shows only ONE possible path along which energy can move through an ecosystem.
A food web consists of many overlapping food chains in an ecosystem.
The arrows show the direction the energy is traveling.

25. ENERGY PYRAMID When an organism eats, it obtains energy.
The organism uses some of this energy to move, grow, reproduce, and carry out other life activities.
Only some of the energy obtained is available to the next organism in the food web.
An energy pyramid is a diagram that shows the amount of energy that moves from one feeding level to another in a food web.

26. ENERGY PYRAMID:
Carnivores Least Energy Third-level Consumers Carnivores Second-level Consumers Herbivores First-level Consumers Producers Most Energy

27. ENERGY PYRAMID
Only about 10% of the energy at one level of a food web is transferred to the next higher level
The other 90% is used for the organism’s life processes
Since 90% of the energy is lost at each step, there is not enough energy to support many feeding levels in an ecosystem.
This is why there are few organisms at the highest level in a food web.

29. Limiting Factors
A limiting factor is an environmental factor that causes a population to decrease.
Limiting factors include:
Food & Water: If it runs out… populations will get smaller.
Space: Plants need room to grow or… populations will get smaller.
Weather: temperature & rainfall can kill off populations or make them breed more. Hurricanes & floods can wash away nests…populations will get smaller.

30. Means of Dispersal
The movement of organisms from one place to another is called dispersal.
Dispersal can be caused by:
Wind & Water:
Wind can disperse seeds, spores of fungi, tiny spiders, and other small, light organisms.
Water transports objects that float such as coconuts and leaves which could be harboring small animals.
Other Living Things:
A bird may eat berries and deposit seeds as wastes. Animals may carry sticky plant burs. Humans can also disperse organisms.

31. Limits to Dispersal Three factors that limit dispersal of a species:
Physical barriers – water, mountains, and deserts are hard to cross and can limit movement.
Competition – Find a unique niche or compete for resources.
Climate – the typical weather pattern in an area. Organisms stick to the area they are adapted to.

32. 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?