Planktonic food webs

Question 1

Zooplankton

Rotifers

Answer 1

clear - soft-bodied - with rota (a row of cilia used for filter-feeding - feed on protozoa and bacteria
reproduce asexually in favourable conditions (eggs are diploid in favourable conditions so cannot be fertilised)

Question 2

Zooplankton

Cladocerans

Answer 2

soft-bodied
use legs to move food to mouth for filter-feeding
reproduce asexually in favourable conditions (eggs are diploid in favourable conditions so cannot be fertilised)

Question 3

Zooplankton

Copepods

Answer 3

soft-bodied
legs physically grab food
always produce sexually - save sperm in body for when they need to reproduce

Question 4

what is diurnal migration?

Answer 4

when planktivorous fish are present, zooplankton stay between 40-50m to avoid predation and move to 20-40m at night to feed

Question 5

what is cyclomorphosis

Answer 5

zooplankton make themselves appear smaller so they are less attractive to fish - compress organs

Question 6

how is isotope analysis used to determine food web structure?

Answer 6

determine the ratio of Carbon and Nitrogen isotopes
you are what you eat
carbon related to predation - predatory signature is one more than it’s prey
Nitrogen relates to trophic level - increases 3.4% every trophic level