21-WEEK ASSESSMENT REVIEW

What is commensalism?

One species benefits with no harm or affect on the other.

What is mutualism?

Both species benefit from the relationship.

Ex: an orchid being pollinated by a nectar collecting wasp

What is parasitism?

One species benefits at the expense of or harm to the

other species.Ex: tick feeding on a dog;

mistletoe absorbing nutrients from an ash tree

Why is overfishing bad?

The fish can’t adapt or reproduce fast enough

What is the difference between these 2 pyramids?

The top pyramid, each level supports a lesser amount of biomass.

Bottom pyramid, less phytoplankton can support a larger amount of zooplankton.

Put the following on the pyramid in order of greatest biomass, or energy, or total number.

GrassWolfRaccoon Grasshopper

Grass

Grasshopper

Raccoon

Wolf

Producers

1st Consumer

2nd Consumer

3rd Consumer

How much energy is passed to the next level?

10%

What happens to the other 90%?

Used by the organisms at that level & given off as heat

If there are 50,000 kilocalories of energy at the producer level in a

habitat, how many kilocalories would be at the tertiary consumer level?

50 tertiary500 secondary

5,000 primary50,000 producer

What trophic level contains the most energy?

Producer SecondaryConsumer

Primary Consumer

Tertiary Consumer

Producers

Fox

Cat

Mouse Rabbit

Grass

Rabbits and mice are herbivores that feed on grass. Cats are carnivores & prey on mice. Rabbits are prey to both cats & foxes. What would the food web look like for these feeding relationships?

Fox

Cat

Mouse Rabbit

Grass

Explain which animals would be affected if a disease killed out all the grass.

All would be affected because of lack of food.

In a habitat, horned toads eat ants and ants eat grass. What would happen if the number of horned

toads increased?

The number of ants will decrease & the amount of grass will increase

Where do herbivores get their energy?

Producers

Which organisms are herbivores?

Snails, grasshopper, snow geese

Which organisms are carnivores?Rat, salmon, bald eagle, marsh hawk,

harbour seal, killer whale

Which organisms are omnivores?Vole, Herring, mosquito

What trophic level of a food web would be the most damaging if it

died out?

producers

Can you explain why?

All the energy in the system starts with the producers. All other levels would

run out of food eventually.

The removal of which organisms would have the greatest affect on

the ecosystem?Marsh vegetation (grasses)

What happens to dead animal tissue in an ecosystem?

Becomes nutrients for other organisms

In the nitrogen cycle, what organisms that live in soil and on roots fix or make usable by plants the greatest amount of nitrogen?

Bacteria fix the most nitrogen.

What would happen if decomposers like earthworms were removed from an ecosystem?

The cycle will be disrupted and slowed

What is primary succession?

Regrowth of a community on barren land where no life has inhabited

before

Pseudomonas aeruginosa, a common bacteria, fights off competitors by injecting them with toxic

proteins using a needle like puncturing device…

Good competitor

What are examples of primary succession?

Oceanic volcano eruptions & glacier retreats

What species would appear first during primary succession?

Lichens & mosses

What is secondary succession?

Regrowth of a community after a natural disaster

Ex: forest fire, hurricane, volcano eruption

What type of organisms would grow after soil had formed?

grasses