Lecture 18: Food Webs (Exam 3) Flashcards
1
Q
autotroph and heterotroph
A
auto: self, produces complex organic nutrients
heterotrophs: acquires complex organic nutrients
2
Q
what a food web is and how to read one
A
- a graphical representation of “what eats what” in a community
- arrows go in direction of energy transfer; each arrow is a “link”
3
Q
classifying organisms on food webs
A
- basal species: species without prey
- intermediate species: herbivores and middle carnivores
- top predators: not prey
4
Q
food web connectedness equation
A
- connectedness: maximum number of links; a fraction of species richness (S)
- L/s^2
5
Q
food web density equation
A
- number of links/species
- L/S
6
Q
two hypotheses on the control of species abundance
A
- bottom-up: autotrophs control abundance of species in a community by controlling the upward flow of energy
- top-down: upper trophic levels control the abundance of organisms at lower ones by eating them
7
Q
what assimilation means, and how to calculate energy lost, assimilated, or used in 2^ary production
A
- assimilation: secondary growth + cellular resipiration; only part of acquired nutrients are assimilated, and even less are used for secondary production
- Energy intake = Eresp + Eassim + Ereproduction + Ewaste
8
Q
trophic interactions and why there are no consumers above the tertiary level
A
- trophic interactions are feeding interactions linked in a “food chain”
- there are no consumers above the tertiary level because only 10% of energy is retained at each level ; energy is used in other facets like respiration, reproduction, waste
9
Q
importance of decomposers and what they do
A
- decomposers break down dead organic substances into simple organic or inorganic molecules
- they can be reincorporated into organic things by other organisms
- cycle organic nutrients
10
Q
interpretation of interspecies competition graphs
A
watch videos
