Ecology Lecture 23 Exam 3

Front 1

Number of species in a community

Back 1

Species richness

Front 2

Proportion of individuals in a community represented by each species

Back 2

Relative abundance

Front 3

Curve that plots relative abundance of each species in rank order from most abundant to least abundant

Back 3

Rank-abundance curve

Front 4

Measure of the difference in relative abundances of species in a community

Back 4

Species evenness

Front 5

What does the slope represent in a in a relative abundance vs. ranked abundance graph?

Back 5

The slope= eveness

Front 6

What does going from left to right represent in a in a relative abundance vs. ranked abundance graph?

Back 6

The higher species richness going this way ------>

Front 7

In terms of evenness and richness describe this graph?

Back 7

The purple line has more evenness less richness but the green line has less evenness and more richness

Front 8

Which of the following could cause the relative abundance distribution to change as show?

Back 8

Decreasing effort at sampling species

Front 9

If you increase resources and increase biomass, what are the two pathways that diversity can take?

Back 9

It can either increase because there are more niches, or it can decrease because more competition selects for better competitors

Front 10

What are the five pathways that effect of resource on diversity can have?

Back 10

U-shaped, Negative, None, Positive, Hump-shaped

Front 11

Which type of shape seems to have the most positive effect on on diversity?

Back 11

Hump-shap[d

Front 12

What do experiments that manipulate productivity by adding nutrients to an ecosystem commonly cause?

Back 12

A decline in the species richness of producers

Front 13

What is happening in this graph?

Back 13

As more resources are added, it becomes negative, thus there is more competition among the plants

Front 14

Why do species richness decline with increases in habitat fertility?

Back 14

Competition

Front 15

Why could communities with a higher diversity of habitats increase diversity?

Back 15

They should offer more potential niches and higher diversity of species

Front 16

Species whose presence substantially affects the abundance of other species in the community

Back 16

Keystone species

Front 17

What is an example of a keystone species and why?

Back 17

Pisaster starfish, east mussels, barnacles, limpets and it affects the abundance of other species

Front 18

Graph of Keystone species

Back 18

Front 19

Keystone species that affect communities by influencing the structure of a habitat

Back 19

Ecosystem engineers

Front 20

What do ecosystem engineers do?

Back 20

Niche construction

Front 21

Diversity highest when disturbance intermediate

Back 21

Intermediate disturbance hypothesis

Front 22

What are some examples of disturbances?

Back 22

Fires, floods, tornadoes, land use change

Front 23

Graph of intermediate disturbance hypothesis

Back 23

Front 24

One linear part of a web

Back 24

Food chain

Front 25

organisms that eat at the same levels (same level organisms in a food web)

Back 25

Trophic level

Front 26

What are some trophic level examples?

Back 26

Producers, consumers,

Front 27

What level has the most biomass in a food web?

Back 27

Grassese and the bottom (the producers)

Front 28

Levels of a food web

Back 28

Producers at the bottom, then consumers like the red squirrel or snowshoe hare and then the 2 prime consumers like a wolf

Front 29

Food web

Back 29

The interactions and relationships among different species and species levels as it relates to food consumption

Front 30

Within a level, species that feeds on similar items

Back 30

Guild

Front 31

Levels of food web

Back 31

Producers, Primary consumers, secondary consumers, tertiary consumers at the top

Front 32

Chesapeake Bay Food Web Example

Back 32

Front 33

Interaction between two species that does not involve other species

Back 33

Direct effect

Front 34

Interaction between two species that involves one or more intermediate species

Back 34

Indirect effect

Front 35

Indirect effects in a community that are initiated by a predator

Back 35

Trophic cascade

Front 36

Question:

(1) Solid = ?

(II) Dashed= ?

(III) Red =?

(IV) Green = ?

Back 36

(I) Direct (II) Indirect (III) = - (IV)= +

Front 37

Proportion of animals in direct vs. indirect effects

Back 37

Front 38

Indirect effect caused by changes in density of an intermediate species

Back 38

Density- mediated indirect effect

Front 39

Indirect effect caused by changes in traits of an intermediate species

Back 39

Trait mediated indirect effect

Front 40

What happens in some habitats if you increase spiders?

Back 40

Decrease in grasshoppers and an increase in grass

Front 41

Example of how grasshopper behaviors change according to potential predatros

Back 41

Front 42

Abundances of trophic groups determined by the amount of energy available from producers

Back 42

Bottom-up control

Front 43

Abundances of trophic groups determined by the existence of predators at the top of the food web

Back 43

Top-down control

Front 44

Another way to describe bottom up

Back 44

Producers on up

Front 45

Another way to describe top down control

Back 45

From predator down

Front 46

Ability of a community to maintain a particular structure

Back 46

Community stability

Front 47

Amount a community resists changes when acted upon by a distrubance

Back 47

Community resistance

Front 48

Speed of return of a community to its original state after a disturbance

Back 48

Community resilience

Front 49

After disturbance to species composition, new community structure forms and is resistant to further change

Back 49

Alternative stable state

Front 50

When does succession occur in a community?

Back 50

When species replace each other over time

Front 51

T or F: succession always occurs through different mechanisms

Back 51

False, can occur through different ones

Front 52

T or F: Succession always produces a single climax community

Back 52

False, does not always produce a single climax community

Front 53

Species composition of a community changes over time

Back 53

Succesion

Front 54

A seral community is what?

Back 54

is an intermediate stagefound in ecological succession in an ecosystem advancing towards its climax community. In many cases more than one seral stage evolves until climax conditions are attained.

Front 55

Earliest species to arrive at a site

Back 55

Pioneer species

Front 56

Final stage in succession

Back 56

Climax community

Front 57

What is the first seral stage?

Back 57

Bare rock, no soil

Front 58

What is the Final seral stage?

Back 58

Stable community composition

Front 59

What is the clearest way to record succession in a community?

Back 59

Direct observation of changes over time

Front 60

What is a modern example of observing succession?

Back 60

Mt St. Helens from 1980 to now has moved toward its climax plant communities

Front 61

What is an early example of observing succession?

Back 61

Krakatu shrinking island boundary

Front 62

a sequence of communities that exist over time at a given location

Back 62

Chronosequence

Front 63

What has happened at the dunes at Lake Michigan?

Back 63

lakes have lowered, and it has moved closer to climax community