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Flashcards in Trophic positions Deck (21)
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1

sea urchins + starfish

clear away barrens of kelp.
allows starfish to feast on brittle stars and sand dollars

2

Lake Victoria and Nile Perch

-super huge lake in Africa
-500 species of fish, most of which were endemic
-90% were cichlids from haplochromis genus
-Nile perch introduced as sport fish bc British ppl killed a bunch of local fish
-extinction (or near) of a ton of endemic fish including half of the 400 tilapia
-loss of phytoplankton
-algae bloom
-algae die --> anoxia
-killed more fish cuz no oxygen
-tons of snails bc fish weren't eating them
-snail born diseases (Schistomiasis)
-fires needed to dry nile perch
-cut down forests, causing erosion
-pollution and sedimentation of lake killed more fish
-Now nile perch is being overfished

3

Trophic cascade hypothesis

effects of predators can alter multiple trophic levels

4

Autotroph vs heterotroph

autotroph makes own food thru photo- or chemo- synthesis

heterotrophs need to eat other organisms

5

Winemiller's food web

-way too complicated
-had to simplify by only including most common species and leaving out weakest trophic links

6

How to simplify food webs

-group species with similar trophic relations into one group
-isolate one part of community that doesn't interact much with the rest

7

energetic hypothesis

-length of food web is limited by energy transfer
-10% of stored organic matter can be used one trophic level up

8

energetic hypothesis test

limit leaves available to consumers in tree hole communities and then measured levels of trophic cascade

9

Trophic pyramid levels

-primary producers = autotrophs
-primary consumers = herbivores
-secondary consumers = carnivores
-tertiary consumers = carnivores that eat other carnivores

10

Why does energy degradation happen

-limited assimilation
-consumer respiration
-heat production

11

ecological efficiency

percent energy transfer between trophic levels

12

assimilation efficiency

percent of energy stored in food that's not lost through egestion (feces)

13

net production and growth efficiency

-what remains after respiration
-percent of net production energy out of assimilation energy

14

two things that affect assimilation efficiency

-type of organism (heterotherm vs homeotherm)
-type of food

15

who has better assimilation efficiency>?

homeotherms (birds and mammals), not heterotherms

16

Easily assimilated foods vs not

-flesh of arthropods and vertebrates
-plant sap, nectar, seeds

-anything will cellulose, lignin, fiber

17

growth efficiency in different organisms

-low in mammals + birds (1-3%)
-higher in fish (10%)
-much higher in insects (40%)

18

consumption efficiency

percent of plant material eaten by animals vs what is left in environment

low to high: forests --> grasslands --> ocean

-stream doesn't really count

19

photosynthetic efficiency

-how well plants can convert sunlight into growth
- NP/ PAR
-PAR = photosynthetically active radiation

20

top-down control

-trophic cascade
-removal of predator or predators increases population of prey
-e.g. foxes and hares/grouse (not vole?)
-mice + rodents required removal of all predators to stop prey cycling

21

bottom-up control

lemmings controlled by amount of moss available
-slow recovery time