Population+succession

Question 1

Advantage of organisms or species occupying different niches

Answer 1

Reduces competition for food sources

Question 2

Difference between interspecific and intraspecific competition

Answer 2

Interspecific is competition between organism from different species
Whereas
Intraspecific is competition between organism of the same species
E.g food sources

Question 3

Ecosystem

Answer 3

Community made up of living organisms and their interactions with non-living components such as air water

Question 4

Describe random sampling

Answer 4

Use a grid
Use a random number generator to obtain random coordinates
Count number/frequency of plants in quadrat
Large sample (20+) and calculate average

Question 5

Systematic sampling (SPECIES ABUNDANCE CHANGE ACROSS an area)

Answer 5

Transect
Place Quadrats at regular intervals along the line
Count plants
*position of Quadrats shud be random and enough transects so data reliable

Question 6

Percentage cover (AREA)
What is this method only used for

Answer 6

Use a random number generator to determine position of quadrats
Large number (20+)
Divide total percentage by number of quadrats
Stationary populations

Question 7

Describe the mark,release recapture technique

Answer 7

Capture sample mark and release
Use paint dots to mark so it does not harm them and make them susceptible to predation
Take second sample and count marked organisms
No in no population=
No in sample1X no in sample2
——————————————
No marked in sample 2

Question 8

Describe how you would determine how many Quadrats to use when investigating habitat

Answer 8

Calculate running mean
When enough Quadrats this shows little change
Enough to carry out statistical test
Large enough so results reliable
Need to make sure work can be done in time available

Question 9

Measuring species with density

Answer 9

Actual count of all individuals present
time consuming
Some species difficult to count (grass grows in clumps)
Most accurate

Question 10

Measuring species w % cover

Answer 10

Used when too many individuals to count
Stratification can occur

Question 11

Using frequency to measure species

Answer 11

Proportion of Quadrats that contain species
Least accurate

Question 12

What is the mark release capture used for

Answer 12

Moving organisms

Question 13

How is humidity measured

Answer 13

Data logged w humidity probe

Question 14

Pioneer species

Answer 14

Species that first colonise an area

Question 15

Climax community

Answer 15

Final stage in succession
Stable

Question 16

High diversity

Answer 16

Stable ecosystem complex food web high variety of food sources
Lots of habitats niches

Question 17

Describe and explain how succession occurs

Answer 17

Colonisation by named pioneer species
Change in environment
Enabled other NAMED SPECIES TO SURVIVE
Change in biodiversity
Stabillity increases
Climax community represented by name species

Question 18

Explain how the presence of fish in a lake could cause an increase in the number of water beetle species

Answer 18

Fish feed on predators
Or
Beetles feed on faeces

Question 19

Method to ensure sample chosen w out bias

Answer 19

Use coordinates
Random number generator

Question 20

Percentage cover used rather than abundance
Why

Answer 20

Too many to count

Question 21

What does + more temperature lead to

Answer 21

Faster Respiration/enzyme activity more KE /photosynthesis

Question 22

What is + light linked with

Answer 22

Faster Photosynthesis

Question 23

What is ph linked w

Answer 23

Proteins
*change in pH breaks ionic bonds between R groups changes 3•
Changes shape of binding/active site
If enzyme then no longer complementary to substrate so substrate cannot bind

Question 24

Why may diversity in one area be greates

Answer 24

Greater variety of food sources
More habitats/niches

Question 25

Each Species of fish had adaptations to shape of its mouth
Suggest how shape of mouth is adaptation to its niche

Answer 25

Diff mouth eats diff food
Competition between species reduced/interspecific competition reduced

Question 26

Features of climax community

Answer 26

Stable community
Stable populations
Abiotic factors constand

Question 27

Species that are present change during succession
How

Answer 27

Microorganism change abiotic conditions
Making conditions less hostile

Question 28

Give 2 types of factors that cause PHENOTYPIC variation

Answer 28

Environment
Mutation/meiosis/alleles

Question 29

What is allopatric speciation

Answer 29

New species form from different populations
In different areas/isolated populations

Question 30

Sympatric speciation

Answer 30

Formation of new species/reproductive isolation
From a population in the same area/ without geographical isolation

Question 31

Explain how sympatric speciation may have occurred
In relation to question

Answer 31

Mutation occurs

Correct e.g. of isolating mechanism
e.g.
temporal − different breeding seasons / feeding times /
ecological / behavioural − different courtship displays / different niches / habitats / feeding areas /
mechanical − mismatch of reproductive parts /
gamete incompatibility − sperm killed in female’s reproductive tract /
hybrid inviability / hybrid infertility;
Ignore references to “genetic isolation” or “reproductive isolation”
Different selection pressures operate / changes in allele frequency / divergence of gene

Question 32

Evoluion

Answer 32

Change in allelic frequencies in a population

Question 33

Speciation

Answer 33

Evolution of a new species from existing species

Question 34

Genetic drift

Answer 34

Bottleneck
RANDOM increase/decrease in alelic frequency
Has a big impact on small populations
As leads to a significant change in allelic frequency

Question 35

Founder effect

Answer 35

Change in allelic frequency due to migration of fertile individuals

Question 36

Describe what is meant by sympatric speciation

Answer 36

· NOT Geographical isolation;

· Leads to reproductive isolation

· Separate gene pools / no interbreeding (between populations);

· Selection for different/advantageous, features/characteristics/mutation/ /allele;

· Differential reproductive success / (selected) organisms survive and reproduce;

· Leads to change in allelic frequencies;

Cannot breed/mate to produce fertile offspring.