uh oh predator alert

Question 1

herbivory is divided into consumption of two thingys (types of organisms)

Answer 1

macrophages and microscopic algae

Question 2

what organisms eat phytoplankton

Answer 2

invertebrates and fish

Question 3

what eats periphyton

Answer 3

micro organisms

Question 4

how does grazing affect algae structure (in terms of biomass, diversity and types of species)

Answer 4

• algae being eaten = less biomass
• changes which types of algae are present (small algae too short to be grazed)
• grazers eat small pockets of algae on a rock at a time, so that can affect which species are left over in each pocket

Question 5

how does grazing affect algae function (in terms of primary production, biomass, nutrient cycling)

Answer 5

• less algae = less photosynthesis = less primary production
• increase production per unit biomass because algae never gets old enough to have slow/weak photosynthesis production because it’s being grazed - lots of young algae with fast photosynthesis
• young algae are fast growing so they need lots of food = faster nutrient cycling

Question 6

why are many tropical fish grazers?

Answer 6

because lots of primary production all year round in tropical areas so lots of food

Question 7

some types of macrophages and algae are not appetizing to eat - says some organisms. why?

Answer 7

low nutrient content, toxins, too tough to digest

Question 8

what is detritus

Answer 8

dead stuff

Question 9

detrivory (eating detritus) is dominant food source when:

Answer 9

not a lot of light = low primary production
and lots of detritus around

Question 10

examples of places with hella detrivores

Answer 10

benthic areas of lake, small forest streams, wetlands

Question 11

detritus is NOT nutritious because ________. what are some solutions that some organisms do to get around this issue

Answer 11

• because have lignins and cellulose which are difficult to digest

solutions
- simultaneously eat bacteria to help break detritus down
- selectively pick high nutritious parts

Question 12

examples of mechanical defenses that prey have adapted

Answer 12

size
claw
spine
shell

Question 13

examples of chemical defenses that prey have adapted

Answer 13

toxins
low nutrient value

Question 14

examples of life history changes
that prey have adapted

Answer 14

reproducing earlier so more likely to make babies but downside is that they’ll probably make fewer babies

Question 15

examples of behavioural defenses that prey have adapted

Answer 15

avoidance

Question 16

prey defense adaptations can be _____ if the predatory shows up

Answer 16

induced

Question 17

adaptions of predators to catch their prey (behaviour, sensory example)

Answer 17

behaviour: sit and wait for prey to show up
sensory: eyes, chemosensory, electrical sensory organs

Question 18

non lethal effects of predation on a population of prey

Answer 18

• non captured prey can still be injured
• changes in life history (reproduce earlier and less)
• restriction of habitat use

Question 19

what is bottom up trophic cascade

Answer 19

primary production controlled by light/nutrients

Question 20

what is top down trophic cascade

Answer 20

primary production controlled by predators in uppper trophic levels

Question 21

which trophic cascade can mimic eutrophication n a lake and explain

Answer 21

top down (production controlled by higher up predators)
- less predators = more primary producers = algae bloom = mimics eutrophication