Unit 3 - Topic 1 - Biodiversity

Question 1

What is biodiversity?

Answer 1

The variation of organisms living within an ecosystem

Question 2

List the 3 types of diversity (what biodiveristy includes)

Answer 2

1. Genetic diversity
2. Species diversity
3. Ecosystem diversity

Question 3

What is genetic diversity? Why is high genetic diversity good?

Answer 3

Refers to the number of different alleles possessed by a species - ie the diversity within the population of a SINGLE SPECIES

The greater the genetic diversity, the more likely a species will survive environmental changes

Question 4

What is species diversity?

Answer 4

Refers to the number of different species present in an ecosystem

Question 5

What is ecosystem diversity?

Answer 5

Refers to the variety of different ecosystems in the world

Question 6

How can biodiversity be measured? List the 5 different measures

Answer 6

5 different ecological metrics can be used to determine biodiversity within ecosystems:

1. Species richness
2. Species evenness
3. Percentage cover
4. Percentage frequency
5. Simpson’s Diversity Index

Question 7

What is species richness and how may it be deteremined?

Answer 7

A measure of the number of different species in a given area. (Does not measure the number of individuals of a particular species)

May be determined through the use of a species accumulation curve.

Question 8

What is species evenness and how may it be determined?

Answer 8

Describes the relative abundance of the different species in an area. Similar abundances mean greater species evenness

May be determined using percentage cover/counting individuals

Question 9

If a community is dominated by one or two species, does it have low or high species evenness?

Answer 9

Lower species evenness

Question 10

If a community has a similar abundance of diffferent species, does it have low or high species evenness?

Answer 10

Higher species evenness

Question 11

What is percentage cover and what may it be used for?

Answer 11

Measure of the proportion of an area covered by the organism

It is used to estimate the abundance of plant species. For example, measuring ground cover (area of soil covered by plants) or canopy cover (total area covered by treetop)

Question 12

State the formula for percentage cover, and the process

Answer 12

%cover = (number of squares covered/total number of squares) * 100

A quadrat is placed over area suveryed - certain rules should be followed

Question 13

What is percentage frequency?

Answer 13

Measure of the appearance of a plant within sample quadrats. (quadrats within area are sampled randomly and each quadrat containing a plant is scored)

Question 14

State the formula for percentage frequency

Answer 14

= (no. of quadrats containing the species/no. of quadrats sampled) * 100

Question 15

What is Simpson’s Diversity Index? (SDI) Explain what the number means.

Answer 15

A measure of diversity which takes into account both the species richness and species evenness of the area.

Number between 0 &1 - the closer to 1, the greater the biodiversity

Question 16

State the formula for calculating SDI

Answer 16

SDI = 1 - (sum of n(n-1))/N(N-1)

Question 17

Define environmental factors (ecological factors), and limiting factors (are they biotic or abiotic)

Answer 17

Any factor that influences living organisms.

Environmental factors that limit the distribution, growth, or abundance of an organism or population is considered a limiting factor. They can be both biotic and abiotic factors.

Question 18

List examples of abiotic factors

Answer 18

light intensity
water availability
temperature
nutrient availability
pH
oxygen availability
wind (speed & direction)
humidity
precipitation
salinity
turbidity
(non living factors)

Question 19

List examples of biotic factors

Answer 19

partners for mating
prey/predator relationships
competitors (for food/land)
symbiotic relationships
presence of disease
(living factors)

Question 20

Explain the law of tolerance

Answer 20

According to the law of tolerance, populations have optimal survival conditions within critical minimal and maximal thresholds. As a population is exposed to extremes of a particular limiting factor, the rates of survival decrease

Question 21

Name and explain the three regions of tolerance on the bellcurve

Answer 21

1. Optimal zone (preferred niche) - central portion of curve - conditions favour maximal reproductive success and survivability
2. Zones of stress (marginal niche) - regions adjacnt to optimal zone - organisms can survive w/ reduced reproductive success
3. Zones of intolerance (unavailable niche) - outermost regions - organisms cannot survive (extremes of the limiting factor)

Question 22

What impacts the abundance and distribuation of a population within an ecosystem?

Answer 22

The presence and absence of environmental factors - e.g. temperature

Question 23

What are the two main scales used to compare between ecosystems? Define them

Answer 23

1. Temporal scale - measuring ecological change over time
2. Spatial scale - measuring ecological change over space/distance

Question 24

Define abiotic and biotic substrates

Answer 24

A substrate is a surface (ie. rock, soil, etc) on which an organism (plant, fungus, animal) lives. This can include biotic or abiotic materials and animals

Question 25

Explain the climate factors affecting organisms (on land and ocean)

Answer 25

LAND
temperature
humidity
rainfall
water availability

OCEAN
temperature
oxygen availability
light availability
salinity
turbidity

THIS MAY VARY TERMPORALLY OR SPATIALLY ACROSS ECOSYSTEMS