Chapter 2: Interactions in Ecosystems pg. 32

2.1 Types of Interactions p. 34Symbiosis:

- is a biological relationship in which two species live closely together over time.

- Helps each species survive by providing food, shelter and protection.

- 3 types of relationships exist:a. Parasitism

b. Mutualism

c. Commensalism

a. Parasitism

• One partner is called the “host” and the other a “parasite”.

• Host is usually bigger and is harmed

• Host does not usually die but their lifespan may be shortened.

• Parasite obtains food and shelter from host and benefits.

• Parasites can be internal or external.

Internal Parasites

• Live inside bodies of hosts

• May stay a long time.• Ex. Tapeworms,

roundworms

External Parasites

• Live on the surface of hosts

• May stay a short time to feed and reproduce

b. Mutualism

• Both partners benefit

• Ex. Lichens, bees and flowers, termites

lichens

• Grow on solid surfaces like rocks and trees

• Consist of an algae and a fungus living together

Lichens

• Algae makes sugar just like plants which is food for both

• Fungus anchors both organisms to a surface and absorbs water needed by both

Insects and flowers

• Insects carry pollen away and help reproduction

• Flower provides food (nectar) to the insects

mutualism

• Bacteria living inside humans

• Birds living on zebras and rhinos

• Algae living on backs of spider crabs

• Microorganisms living in the gut of termites

• Sea anemones and hermit crabs

c. Commensalism

• One partner benefits and the other does not gain or lose anything.

Ex. Barnacles on the back of a whale

Ex. Birds follow army ants

Birds riding on water buffalo

Food and Populations pg. 37

• Symbiosis helps an organism survive because it provides: ______________

• Predators – are organisms that hunt and kill their food– Are carnivores or meat eaters– Ex. ______________________________

Cont’d…

• Prey

- are organisms that are hunted and killed for prey.

- ex._____________________________

Predator-Prey Relationships

• often show changes in the size of each population that repeats in a cycle.

• size of predator population is affected by the number of prey that are available

• size of predator population is affected by the number of prey hunting them

Lynx- Hare Populations

2.2 Roles of Organisms in Ecosystems (Niche) Producer

• Organisms that make their own food through a process called photosynthesis.

• Ex. Plants, algae, some bacteria

Consumer• Organisms that get

their food by eating other organisms

a. Herbivores

b. Carnivores

c. Omnivores

d. Scavengers

e. Decomposers

Photosynthesis – Producers/Autotrophs

Bacteria – algae that live ina pond

Plants – over 300 000 species on Earth

Diatoms – plankton live in the ocean

Types of Consumers

a. Herbivores

- eat only plants

ex.

b. carnivores

• Hunt and eat other animals

• Ex.

c. omnivores

• Eat both plants and animals

d. scavengers

• Eat remains of dead plants and animals

• Ex. Seagulls, crows, blackbears, raven, hawk, eagle

e. decomposers

• Do not ingest food

• Release digestive juices to the environment which break down remains of dead organisms and waste

• Absorb the digested from back in

• Ex. Bacteria, fungus, insects

Decomposers and Food pg. 43• Food can be protected from decomposers

by:1. Keeping microorganisms out of it. (bacteria,

fungus, )

a. Vacuum packed products

b. Caning

c. Sealed plastic bags and containers

d. Freezing

e. Freeze Drying

f. Salting and pickling

Micro-organisms

• Need a source of food

• Need water

• Have a range of tolerance for temperature and ph

a. Vacuum Packed Products

b. Canning

c. Containers and bags

d. Freezing food

e. Freeze Drying

f. Salting food

Pickling food

2. Killing or slowing growth of microorganisms already on it.

a. Washing hands, utensils and countertops before handling food

b. Washing food

c. Cooking food well

d. Radiation

Microbes Make Food –Fermentation (to bubble)

• Is a process carried out by microorganisms where they break down sugar and produce different kinds of waste products:1. Lactic acid – stops growth of harmful

bacteria, used to make dill pickles, sauerkraut,

pickled cabbage, some sausages, cheese

2. Alcohol – used to make beer, wine

Cont’d

3. Carbon dioxide – used to make bread rise

Fermentation in beer

Fermentation in cheese

Fermentation in bread.

Food Webs

Energy Pyramid

2.4: Cycles of Matter in EcosystemsNutrients:

- Are substances contained in food that are needed in small amounts by all living organisms

- Are taken in from the environment by producers

- Are transferred to consumers through a food chain/web

- Are reused when living organisms die and are broken down by decomposers.

Cont’d…

Ex. Minerals come from the soil

Ex. Water

Ex. Carbon comes from carbohydrates and carbon dioxide,

Ex. nitrogen comes from protein

Nutrient Cycles

• Are processes that move nutrients back and forth between the biotic and abiotic parts of the ecosystem.

• Ex. Carbon – Oxygen Cycle

• Ex. Nitrogen Cycle

• Ex. Phosphorous Cycle