Ecology - Lecture 14 - Biodiversity

Front 1

Global Biodiversity:

What is the estimated range of the number of species that exist on earth?

What is estimated to be their actual number?

How many of those have actually been named?

Back 1

Range: 5 - 30 million species

Estimated: ~15 million

Named: 1.5 million (10%) have been named

Front 2

What are 2 variables used to measure Biodiversity?

Back 2

Species richness

Species evenness

Front 3

Define:

Species richness

Back 3

The number of species in a community

Front 4

Define:

Species evenness

Back 4

Relative abundance of each species in a community

Front 5

Rare and Common species:

As a general rule, communities have _____ common species and _____ rare species.

Back 5

...few...

...many...

(There are generally more rare species than common)

Front 6

What species was used as an example of how there are relatively FEW commons species within a community, and relatively MANY rare species?

What type of curve would a graph of this pattern produce?

Back 6

[19.1] Krebs pg. 379

Lepidopterans in England

~35 species that consist of 1 individual
~3 species that consist of 40 individuals.

Graphed, this produces a "hollow curve".

Front 7

Converting the x-axis on a graph of a "hollow curve" to a logarithmic scale produces a...

Back 7

Log-Normal Distribution

...fits many communities for a variety of taxa.

Front 8

Geographic patterns of Biodiversity:

Describe the "Latitudinal Gradient"

Back 8

A general pattern in Biodiversity where:

- The highest diversity occurs in the tropics

- Diversity decreases as you move toward the poles.

Front 9

Geographic patterns of Biodiversity:

What are 2 species examples used for the "Latitudinal Gradient" pattern of biodiversity?

Back 9

1) Copepods in marine communities

2) Breeding land birds [19.7]

Front 10

Geographic patterns of Biodiversity:

What is an organism example that doesn't fall under the "Latitudinal Gradient" pattern?

Back 10

North American Mammals

- 15 species in Canada to over 150 species in Central America

Front 11

Geographic patter

Describe 4 characteristics (in terms of species biodiversity) of figure [19.9] (pg. 384)

Back 11

1) N-S gradient
2) Topographic relief
3) E-W gradient
4) Peninsular "lows"

Front 12

What are the 6 ecological and evolutionary factors that ecologists agree can have an influence on Biodiversity?

(No description of factors)

Back 12

TABLE [19.2] (pg. 387)

1) Evolutionary Speed Hypothesis

2) Geographic Area Hypothesis

3) Interspecific Interactions

4) Ambient Energy Hypothesis

5) Productivity Hypothesis

6) Intermediate Disturbance Hypothesis

Front 13

TABLE [19.2] (pg. 387)

Describe the:

Evolutionary Speed Hypothesis

Back 13

History affects community diversity.

1) Evolutionary rates are faster in tropics.

2) Diversity is the product of evolution

3) Disturbances - glaciation, etc.

*FIG [19.11] (pg. 387)

Front 14

TABLE [19.2] (pg. 387)

Describe the:

Geographic Area Hypothesis

Back 14

Larger areas support more species:

1) Larger areas have more habitats.

2) Larger areas have larger populations (thus a lower risk of extinction)

3) Tropics have greater land area than temperate and polar regions.
- Geographic area is not a good predictor of tropics-to-pole diversity patterns.
- Important to patterns of island biodiversity

Front 15

TABLE [19.2] (pg. 387)

Describe the:

Ambient Energy Hypothesis

Back 15

Energy available determines and maintains biodiversity.

1) Climate determines energy availability.

2) Solar radiation, temperature, and water.

3) Table climates have more energy available to support more species.
- This hypothesis explains tropics-to-pole diversity patterns for many groups

* FIG 19.20 (pg. 394)

Front 16

TABLE [19.2] (pg. 387)

Describe the:

Productivity Hypothesis

Back 16

Greater plant productivity means greater diversity

1) Tropics have greater productivity than poles.

2) Data do not support this hypothesis

3) Diverse communities found on nutrient poor soils...
...low diversity found on nutrient-rich soils.

Front 17

TABLE [19.2] (pg. 387)

Describe the:

Intermediate Disturbance Hypothesis

Back 17

Disturbance determines biodiversity.

1) Important to local, small scale patterns

2) Competitive exclusion in equilibrium communities

3) Disturbances prevent equilibrium

4) Disturbances include:
{predation, herbivory, changes in physical factors, catastrophes (fire)}

5) Frequency of disturbance determines diversity.

FIG [19.23] (pg. 396)

Front 18

Intermediate Disturbance Hypothesis:

What is the main message for:
FIG [19.23] (pg. 396)?

Back 18

That maximum diversity occurs at some *intermediate* of disturbance.

Front 19

Intermediate Disturbance Hypothesis (IDH):

What example was used as a counterargument for the IDH?

Back 19

[19.25] (pg. 397)

Experimental burning of tallgrass prairie in Kansas

- Plots were burned with different frequencies but...

- ...no sign of intermediate disturbance maximizing diversity of plant communities was found.

Front 20

Biodiversity is in _____.

Back 20

☠ CRISIS! ☠

Front 21

Biodivdersity "Hotspots" are based on...

Back 21

...the richness of endemic species.

Front 22

How many Biodiversity "Hotspots" have been found?

What percentages of the world's:
- Plant species
- Vertebrate species
- Land surface used

...are expressed in these Hotspots?

Back 22

34 Hotspots identified.

50% of the world's plant species
77% of the world's vertebrate species

covers only 2.3% of the earth's land surface.

Front 23

True/False:

All Biodiversity "Hotspots" are located in tropical environments?

Back 23

FALSE!

[19.10] (pg. 385)

Hint 23

The answer ends in 'e'.