Do now: Write in your notebook the answer to the 2 following questions.

1. Distinguish (similarities and differences) between scavengers

and decomposers.2. Distinguish between predation

(what predators do) and scavenging (what scavengers do).

Scavengers and decomposers

• Scavengers (water snails, hyenas and vultures) consume dead animals.

• Decomposers (fungi, some bacteria) are organisms of decay and break down the remains of both dead plants and animals. Their waste products release substances that can be reused by other members of the ecosystem.

Predation and scavenging

• Both are done by carnivores• Obtain prey in different ways• Predators (lion) hunt and kill prey• Scavengers (hyena) feed off dead carcasses

that they find

LichenHow would you describe this organism?

Lichen• Lichen grows on the bark of trees, on rocks

and on soil. They are usually the first organisms to grow on bare rock.

• They are also abundant in the Arctic where they are eaten by reindeer and other animals.

Lichen

• Lichens are made of green algae (or blue-green bacteria) and a fungus that live together.

• Neither one could survive on their own.• What problem or question does this bring to

mind?

Aim

• Why do the algae and the fungus in the lichen need each other to survive?

Describe green algae and its role in food chain?

• Green algae are autotrophs• Like other autotrophs they convert sunlight

energy into nutrients via photosynthesis• (Cyanobacteria, or blue-green bacteria can

also carry out photosynthesis. They are simpler than algae and have 2 photosynthetic pigments, chlorophyll and phycocyanin)

Describe fungus and the role it plays in food chain

• Fungi are decomposers

Describe the structure of lichen under a microscope

White filaments-fungi

Green cells algae

Why do they live together?

• Based on your observations of the structure of a lichen, what can you hypothesize about the function of the algae and the fungus in the lichen?

• Algae provides nutrients to the fungus.• Fungus provides protection, moisture

and needed elements to the algae

Why is the close association in the lichen beneficial to both the algae and

fungus?

• Each get something from the other that they need.

• This relationship is a type of symbiosis, where both organisms benefit from the relationship, called mutualism

Symbiosis

• Symbiosis is where organisms live in close association

• Mutualism-type of symbiosis that benefits both organisms (example lichen-algae and fungus)

What is THIS?

Parasitism

• Parasitism is a symbiotic relationship where the parasite benefits, but the host is harmed

• Example: Tapeworm lives inside host’s (human) intestine to absorb nutrients directly without their own digestive system

Another type of symbiosis

• http://www.youtube.com/watch?v=Wj5iqTW8GnE

Clownfish live among anemones

Commensalism

• Commensalism is when one organism benefits but the other is not affected

• Example Clownfish and anemone. Anemone provide shelter and protection to fish, but anemone get no benefits and are not harmed

Niche in an ecosystem

• Each organism in an ecosystem occupy a particular place, called its habitat

• Each organism also has a particular role or job within the ecosystem, called a niche.

• In a balanced ecosystem, each species occupies its own niche

• Predict what would happen if 2 different organisms occupied the same niche in an ecosystem.

What would happen if 2 different organisms occupied the same niche?• They would compete with each other• The stronger or better one at competing or

doing its job would survive and the other one would be eliminated from its niche.

• It would either die out, move somewhere else or try to take on a new, closely related niche

Competition

• Competition among living things• Habitat= place• Niche = role or job

Interspecific competition

• Between different species competing for a niche

• Better adapted species survives• Less successful species eliminated

Intraspecies competition

• Competition within individual members of a population (same species)

• Darwin’s survival of the fittest• Only the strongest and fittest individuals

survive

Work with your partner to classify each of these relationships

• Heartworm in dogs• Orchids and trees• Flowers and bees

Homework

• Miller and Levine: read pages 90-93, answer page 97 questions # 2, 4, 5 and page 117, questions #25-29

• Materials and methods for Bottle ecosystem lab is now due Monday