community ecology

Question 1

What is an ecological community?

Answer 1

• the interaction, not the physical presence of organisms or populatons in a place
• how they interact
• if not interacting, not a community
• interacting creates a populations factor

Question 2

Describe competition.

Answer 2

• you do work in my prsences and ido work in yours
• intraspecifc competition (within) (ex. battle for mates)
• interspecific (competition) (ex. battle for food)
• any interaction between 2 species where an increase in density of either species causes a decrease in the per captia population growith rate of another ( my numbers go up and yours go down, and vice versa)
• struggle for limiting reasources
• mutually negative ineraction

Question 3

What is the competitive exclusion principle?

Answer 3

• two species can not use the same resource in the same way and coexist
• for two species to coexist: intraspecific competion> interspecific competition (compete with own species more than compete with other)
• if inter> intra, one species is competitively excluded
• “the ghost of competition past”
• both are negatively impacted but one is negatively impacted less

Question 4

Define and explain the competition coefficient.

Answer 4

• the species i is proportional effect that species j has on species i
• the effect species j has on species i, in species 1 units
• ect.. Aij= 0.25 , Aij= 1

Question 5

Differentiate consumption and classical predation?***

Answer 5

• predation is compettion between the predator and the prey (ex. bunny and wolves)
• consumption is competition between two spcieces eating the same prey

Question 6

Define functional response. Differentiate between a Type I, II and III functional response.

Answer 6

• per captia consumption rate of a predator given prey density
• based on the time needed for two key predator behaviours: searching for prey and handling prey
• TYPE 1: first order, exponent is one, regardless of prey density, always same result. for example, spiders will always catch prey in their web
• TYPE 2: saturated, as prey density decreases slowly, decreased attack (functional response), MOST COMMON because predators can get prey quickly but theres only so fast you can eat it
• TYPE 3: rate of response increases, low prey density, exponential consumtpion and then saturation, takes them time to find their prey so consumption is low, so they stay in the same spot and then consumtpion is saturated. i found it so im not looking for anything else; dont look for other prey because wasting energy (ex. lady bug)

Question 7

In the context of population regulation, differentiate top-down versus bottom-up control.**

Answer 7

lokta voltera? see notes

Question 8

Differentiate fundamental vs. realized niche.

Answer 8

• fundamental: what can be used to survive (ex. there is food)
• realized: after interactions are taken into consideration (ex. there is competiton for food)
  SEE NOTES
• n-dimensional hypervolume= funamental niche
• n-dimensional hypervolume + interactions= realised niche

Question 9

Define disturbance and the intermediate disturbance hypothesis?

Answer 9

• disturbance: any factor which causes a decrease in the number of individuals in a population. therefore any population regulating factor.
• intermediate disturbance hypothesis: intermediate level of disturbance has the most number of species. low disturbance= low number of species that can sustain conditions or compete the best; high disturbance, only some speices can sustain
  SEE NOTES
• ex. community structure changes in the kickappo river

Question 10

How can disturbance affect competitive interactions? Predation interactions?**

Question 11

types of interactions (inter specific)

Answer 11

• competition
• consumption (predation, parsitism,herbivory)
• mutualism
• commensalism (null affect)

Question 12

interaction table

Answer 12

species 1
sp2 neg pos

neg competition consumption

pos consumtion mutuaism
SEE NOTES

Question 13

mechanisms of comoetition

Answer 13

• ways to categorize based on what competing for
• different categories f competition:
• comsumption
• preemption
• allelopathy
• territoriality

Question 14

consumption competition

Answer 14

• one species inhibits another by ingesting a shared resource
• ex. hynea eating prey so lepord cant have it

Question 15

premptive competition

Answer 15

• mainly among sessile organisms, when the mere presence of one species reduces a shared resource for another species
• competition for space
• sessial organisms stay in one place and cant locomote
• you cant grow because im there, i get bigger butthen you are in my way, so i cant get bigger

Question 16

allelopathy

Answer 16

• one species inhibits anither by changing the chemical composition of a resource
• releases an allelochemical: a pheromone beteen 2 species
• ex. changes ph of environment

Question 17

territorial competition

Answer 17

• one species inhibts access of another species to a resource via behavioural aggression
• mates etc: have their territory. dominatnt male protects their territory an prevents others from getting females

Question 18

what is consumtption

Answer 18

classical def:
- any interaction between 2 species where a density increase in spcies i (consumed) causes an increase in the per capita population growth rae of species j (consumer)
AND
- a density increase in species j causes a decrease in the per capita population growth rate of spcies i

Question 19

examples on consumption

Answer 19

• classical predation
• parasitism
• herbivory
• seed predation

Question 20

two species model

Answer 20

• lotka volterra model
• based on logisitic
• SEE NOTES

Question 21

what is niche

Answer 21

• the place a species occupies in a community/environment
• the environmental requirements of a spcies
• any n-dimensional hypervolume where n equals the number of physcos and biological factors important to the survival and reproduction of a species

Question 22

case study: jellification of norther temperate lakes**

Answer 22

• ## acid rain/sulpher cycle