LEC19

Question 1

Define

Life history

Answer 1

The traits of a population that affect an organism’s schedule of reproduction and survival
ex: Max size, lifespan, age of first reproduction, survivorship curves

Also tradeoffs: size of offspring vs multiple offspring, for example

Question 2

What are the two models of population growth?

Answer 2

Exponential (density-independent) and logistic (density dependent)

Question 3

Describe

A case of exponential growth

Answer 3

Rebound of a drastically reduced population or a population brought into a new environment

Often followed by negative feedback: + density = + deaths

Question 4

Define

Metapopulation

Answer 4

Group of populations that are connected by immigration and emigration

Question 5

What makes a population within a metacommunity important?

Answer 5

• Very large (represents a large percentage of metacommunity)
• Connected to a lot of other populations by dispersal (movement is a type of dispersal, only done by organisms that can move)

Question 6

Define

Ecological interactions

Answer 6

Interactions between species occur when the actions of individuals of one species directly/indirectly affect the vital rates (death, birth, growth) of other species

Question 7

Define

Interspecific interactions

Answer 7

Defined by whether they help, harm or have no effect on the survival and/or reproduction of species involved

Question 8

What are the two types of mutualism

Answer 8

• Obligate, where one species cannot live without the other (ex: lichen)
• Facultative: both species can survive alone

Question 9

Define

Facilitation

Answer 9

(+/+ or +/0) is an interaction in which one species positively affects another species without direct contact

Question 10

Define

Exploitation

Answer 10

One species benefits at the expense of the other
(predation, herbivory, parasitism)

Question 11

Define

Aposematic coloration

Answer 11

Colors displayed by animals with effective chemical defenses; bright colors

Question 12

Define

Parasitism

Answer 12

• +/-, the parasite derives nourishment from its host, which is harmed in the process
• Endoparasite: lives within host body
• Ectoparasites: live on external surface

Question 13

What is the difference between predation and parasitism?

Answer 13

A predator kills its prey before consuming it, a parasite consumes but does not kill the host immediately

Parasitoids, on the other hand…

Question 14

Define

Competition

Answer 14

(-/-), occurs when species compete for a resource in short supply, or when both species directly negatively affect each other’s ability to survive

Question 15

Define

Fundamental niche

Answer 15

• Niche potentially occupied by that
  species.
• Range of potential abiotic and biotic
  conditions and resources that would
  allow the persistence and growth of
  that species

Question 16

Define

Realized niche

Answer 16

Niche actually occupied by a species when coexisting with other species in nature

Question 17

Define

Species richness

Answer 17

• Way to measure how diverse a community is
• Total number of species in the community

Question 18

Define

Evenness

Answer 18

• Relative abundance of species
• Community perfectly even if all species share the same % of total abundance
• Total abundance is the total number of individuals in the community

Question 19

Why care about diversity?

Answer 19

• Can be more productive
• Can be more stable (less variable biomass)
• Can be harder to invade
  *Could also be a bigger source of new pests

Question 20

Define

Trophic cascade

Answer 20

When the changing abundance of a predator leads to its prey increasing, and that species’ prey decreasing, and so on