Ecological Roles and Relationships / Symbiosis (sec 2.2 and 2.3 pg 25-32) Ecological Roles and Relationships / Symbiosis

The organisms in each ecosystem have different roles....

Producers or autotrophs = are organisms that make their own food (usually through photosynthesis). plants are producers on land (trees, shrubs, grasses, flowers, etc.) algae are producers in aquatic environments (including seaweeds, and also phytoplankton - which are microscopic algae)

Consumers or heterotrophs = organisms that consume other organisms or biotic waste in order to survive. Herbivores or primary consumers = consumers that eat producers.

Consumers or heterotrophs = organisms that consume other organisms or biotic waste in order to survive. Carnivores = consumers that eat other consumers (primary and secondary).

Consumers or heterotrophs = organisms that consume other organisms or biotic waste in order to survive. Omnivores = consumers that eat both producers and other consumers.

Consumers or heterotrophs = organisms that consume other organisms or biotic waste in order to survive. Detrivores = consumer organisms that feeds on the waste material in an ecosystem, including dead organisms, plant debris and animal feces (Fig.5 pg.27)

Consumers or heterotrophs = organisms that consume other organisms or biotic waste in order to survive. Decomposers = consumer that breaks down the complex molecules found in dead organisms into simpler molecules by process of biodegredation. VERY important in ecosystem – lots of invertebrates (e.g. worms and insects), bacteria and fungi. They make the nutrients available to producers by putting it in the soil.

Consumers or heterotrophs = organisms that consume other organisms or biotic waste in order to survive. Predator = an organism that actively hunts another organism and kills it for food. Prey = an organism hunted by another organism.

Predator – Prey cycle = the population cycles that predators and preys go through (constantly fluctuating). Cycle begins when prey population decreases as preds eat prey; then predator population decreases because of reduced food available; then prey population bounces back because of fewer predators. Lynx-snowshoe hare relationship in Northern Canada well-studied.

In natural populations, there can be many other environmental factors that affect abundance of organisms (e.g. drought affects plants affects herbivores affects.....)

There are different types of relationships between organisms There are different types of relationships between organisms. Symbiosis refers to any close relationship between different species (often called a symbiotic relationship), including...

Mutualism = a relationship in which both species obtain some benefit from the interaction (e.g. lichen Fig 1 pg.30).

FUNGUS FARMING ANTS!?! http://www.youtube.com/watch?v=cWtSHJJJGcc

Commensalism = an interaction in which one organism benefits while the other is unaffected. (e.g. whale/barnacle Fig.2 pg. 30; some biologists argue this doesn’t exist...)

Parasitism = when one organism lives and feeds on, or in, the body of another organism called the host. Parasite benefits, host is harmed. Parasites can have a positive role in ecosystem, as they can control species’ population growth and over-abundance (may ensure strongest and healthiest members survive).

NASTY WASP PARASITES http://www.youtube.com/watch?v=rLtUk-W5Gpk

Biologists estimate up to 25% of all animal species may be parasites!!! Plant parasites exist too (Fig 4 pg.31) – they steal nutrients from the host instead of through photosynthesis

PLANT PARASITES.... http://www.youtube.com/watch?v=SwfhYYnmLYM

pg 29 1-6, 9, 11 pg 32 1-4, 7-11