Community assembly

Question 1

Trophic cascade
direct and indirect

Answer 1

indirect interaction in which predator of a predator
(or herbivore) benefits the producer indirectly
-Direct interactions in trophic cascade are the negative
predator-prey interactions\
-indirect is positive impact of carnivore on producer
enemy of my enemy is my friend

Question 2

Trophic facilitation

Answer 2

indirect effect in which one species benefits
another via a positive interaction (mutualism)

Question 3

level >3

Answer 3

1° / 2° predators

Question 4

Level 2

Answer 4

Herbivores

Question 5

Level 1

Answer 5

Primary producers

Question 6

guilds

Answer 6

Groups of species that exploit
the same resources in related ways

Question 7

why is the food pyramid upside down in aquati environments

Answer 7

primary producers in aquatic environments are short lived and consumed quickly, more abundancy

Question 8

change in ecosystem if removed:
Rare Species
Moderate abundance
Foundational Species
Keystone Species

Answer 8

rare:
-Not a vital role in the ecosystem
Moderate:
-moderate role
foundational species:
-Dominant/Abundant species, Play a vital vital role
Keystone Species
-Rare species, but vital to the ecosystem

Question 9

Keystone species concept

Answer 9

-An organism that defines the entire ecosystem
-These species have low functional redundancy–> no other species can fill their role
-species that, despite its low biomass, exert strong effects on the structure of communities they inhabit.

Question 10

keystone predators keep prey pops
what does this do

Answer 10

below K,
decrease competition,
* create ecological niches
* increase diversity within communities
keystone species not always predators

Question 11

Dominant species vs keystone species

Answer 11

-Both dominant and keystone species have a high impact on
ecosystems
-keystone species have a high impact despite a low abundance

Question 12

what is a Trophic Cascade

Answer 12

When something happens at one trophic level, it has
repercussions on the rest of the food chain – not just on the
levels that are directly involved

Question 13

he only requirements for keystone status is

Answer 13

• have relatively low biomass in the community
• high impact on community structure.

Question 14

Keystone are not to be confused with:

Answer 14

Umbrella species, or ecosystem engineers

Question 15

umbrella species

Answer 15

-Species that are selected as
representatives of their ecosystem when
conservation plans are being made.
-Protection of Umbrella species will protect a
large amount of co-occurring species

Question 16

ecosystem engineers

Answer 16

Species whose activity creates, or fundamentally alters, habitat

Question 17

differences and similarities between ecosystem engineers and keystones

Answer 17

-The impact of ecosystem engineers may as large as keystones, but they differ in type of impact
* Keystone species are essential due to their trophic effect;
ecosystem engineers are not.
-Like keystones, their abundance does not need to be
high to have an impact on the ecosystem
* But they still can be highly abundant

Question 18

2 types of Ecosystem engineers

Answer 18

Allogenic and Autogenic

Question 19

Allogenic Ecosystem engineers

Answer 19

modify the environment by mechanically changing
the living / non living material from one form to another

Question 20

Autogenic Ecosystem engineers

Answer 20

modify the environment by modifying themselves

Question 21

Indirect interactions:

Answer 21

The relationship
between two species is mediated by a third
(or more) species

Question 22

Direct interactions:

Answer 22

Between two species (e.g., competition, predation, facilitation)