Community structure

Question 1

How does the form of growth influence community structure? (Type of growth)

Answer 1

Determines the spatial structure of the community
- spatial & temporal availability of resources
- microclimate
- spatial complexity
- potential for disturbance

Question 2

Species abundance

Answer 2

The number of species in a given area/environment

• A species is considered abundant when it has a high population relative to the size of the area it inhabits

Question 3

What does it mean to be diverse?

Answer 3

Species are not equally abundant

Question 4

How do dominant species effect other species?

Answer 4

It affects the distribution and survival of other species

Question 5

Species Richness

Answer 5

A measure of the number of different types of species in an ecosystem

• A large number of different species in a habitat represents a higher species richness, and an overall more diverse ecosystem

Question 6

Species Evenness

Answer 6

The relative abundance/amount of each species

Question 7

alpha (a symbol)

Answer 7

Diversity of species within a small area (community)

Question 8

beta (b symbol)

Answer 8

Species diversity between two communities or ecosystems.

Question 9

gamma diversity (y symbol)

Answer 9

Species diversity across communities within a larger geographic area

Question 10

Environmental complexity and species diversity

Answer 10

Positive relationship between complexity and species diversity

• Changes in soil type causes differences in vegetation (Tree height) over a short distance (Trees) - can be caused by fertilization

Question 11

Where are hot spots of species diversity located?

Answer 11

1. Tropics
2. Mediterranean-type systems
3. Mountainous areas

Question 12

Character displacement

Answer 12

• Occurs when similar species that live in the same geographical region and occupy similar niches differentiate in order to minimize niche overlap and avoid competitive exclusion
• The height of a tree height allows different species of birds to locate in different areas of the trees = species diversity (Character displacement)

Question 13

Niche breadth

Answer 13

• The diversity of resources used or environments tolerated by an individual, population, species, or clade
• The range of conditions under which an organism can live

Question 14

Niche separation

Answer 14

• The process by which competing species use the environment differently in a way that helps them to coexist.

Question 15

Why is predation / scavenging important?

Answer 15

Leads to an increase in plant species diversity because the dispersal of seeds occurs when animals eat seeds from plants

Question 16

Keystone predator

Answer 16

Species in which an ecosystem largely depends on that species, so much that if it were to be removed, the ecosystem would change drastically

Question 17

Intermediate disturbance hypothesis

Answer 17

Species diversity is maximized when environment disturbance is neither too rare nor too frequent (Peak represented in the graph)

Closer to 0, low levels of disturbance

Question 18

Diverse communities display?

Answer 18

More productivity, higher resource efficiency (most stable)

Question 19

Diverse communities are less susceptible to what?

Answer 19

The invasion of non-native species and less susceptible to a variety of disease outbreaks

Question 20

What are the effects of invasive species on community structure?

Answer 20

They cause a decline or extinction of native species

Question 21

How do invasive species cause local extinction of native species?

Answer 21

1. Competition
2. Predation, pathogenicity, parasitism
3. Habitat alteration

Question 22

Parasitism

Answer 22

A relationship between the two living species in which one organism is benefitted at the expense of the other (Parasite and host)

Question 23

Pathogenicity

Answer 23

The capacity of a microbe to cause damage in a host

Question 24

What do invasive species do to ensure they succeed in new environments?

Answer 24

They have to escape from predators in the environment with the ability to modify new environment are keys to invasion success