6.3.2 - Population and Sustainability

Question 1

Stages on population graph

Answer 1

Slow growth
Rapid growth - resources plentiful, reproductive rate > mortality rate
Stable state (no growth) - mortality = reproduction
Cannot support a larger pop. due to carrying capacity, small fluctuations

Question 2

Populations can

Answer 2

Remain stable
Rise or fall suddenly
Oscillate up and down w. the reg. pattern

Question 3

Types of limiting factors

Answer 3

Density dependent

Density independent

Question 4

Density dependent

Answer 4

Factors that affect pop. the more they increase in size e.g resources, predators, intra and inter spp comp.
These limiting factors place the carrying capacity on population size

Question 5

Density independent

Answer 5

Factors that affect the the same proportion of the population regardless of size

Question 6

Types of strategists

Answer 6

k and r

Question 7

K selection

Answer 7

Offspring have a high prob of survival 
Heavy parental care and nurturing
Larger organisms
Much lower reproductive rate
Young are altricial, longer lifespans and have overlapping generations

Question 8

Altricial

Answer 8

Born in an undeveloped state and requiring care and feeding by the parents

Question 9

R selection

Answer 9

Produce many low effort organisms
Species grow rapidly
Found in less competitive and low quality environments
Young are precocial
High of mortality so start reproducing earlier
Non overlapping generations, shorter lifespans
Boom and bust (cyclical)

Question 10

Precocial

Answer 10

Born in an advanced state and able to feed itself almost immediately

Question 11

Predator prey interactions

Answer 11

When predator pop increases, more prey eaten
Prey pop decreases, less food available for predator s
W/ less food, fewer predators survive so their pop. decreases
W/ fewer predators, fewer prey are eaten so their pop. increases
More prey = more food, predator pop. increases
Two populations are in eqm and stable due to -ve feedback

Question 12

When does competition occur

Answer 12

When there are not enough resources to satisfy all of the organisms that depend on them

Question 13

How does intraspp comp affect population

Answer 13

Population drops –> comp. reduces –> pop. increases –> pop. drops (oscillates)

Question 14

Examples of interspp comp. affecting population

Answer 14

Red and grey squirrels - Invasive species
May leads to extinction of one species
Greater specialisation to avoid competition
Change in distribution of the species

Question 15

Where does invasive species have a largest effect

Answer 15

Islands

Question 16

Competitive exclusion principle

Answer 16

2 competitive species cannot coexist at the same population level esp if ones staring population is higher than the other

Question 17

Preservation

Answer 17

Keeping habitats/species as they are now (assuming they are currently undisturbed)
Focuses on eliminating any human effects on ecosystems

Question 18

Conservation

Answer 18

Active management of ecosystems by humans to maintain biodiversity
Involves management of ecosystem so that natural resources can be used sustainably and reclamation

Question 19

Reclamation

Answer 19

Restoring ecosystems that have been damaged/destroyed

Question 20

Threats to biodiversity

Answer 20

Over-exploitation of ecosystems by humans
Habitat disruption and fragmentation
Intro of invasive species by humans that outcompete native species to extinction

Question 21

Potential management strategies

Answer 21

Raise carrying capacity by increasing nutrients 
Move individuals to enlarge pop
Encourage natural dispersion using dispersion corridors  between fragmented habitats 
Fencing 
Controlling predators and poachers
Vaccinate individuals 
Prevent pollution/disruption 
Intervene to restrict succession

Question 22

Ethical reasons to conserve

Answer 22

Moral responsibility
All organisms have a right to live
Every species has value in and of itself

Question 23

Why does interspp competition have diff effects in the wild

Answer 23

Species may migrate
Other biotic and abiotic effects on the organism
Availability of resources vary
Organisms may not have exactly overlapping niches

Question 24

Small scale timber production

Answer 24

Coppicing

Pollarding

Question 25

Sustainable management

Answer 25

Carrying out processes indefinitely w/out damaging the ecosystem

Question 26

Coppicing

Answer 26

Stem of deciduous tree is cut close to ground New shoots grow from the cut surface Mature into narrower stems Happens cyclically

Question 27

What is coppicing used for

Answer 27

Fencing Firewood Furniture

Question 28

Pollarding

Answer 28

Sim technique to coppicing | Only done higher up so that the animals cant eat the new shoots

Question 29

Negative of small scale timber production

Answer 29

Labour intensive

Question 30

Rotational coppcing

Answer 30

Divide wood into sections | Cut one each year

Question 31

Why is rotational copppicing good for diversity

Answer 31

Light is still able to reach forest floor as tress never grow tall enough --> increasing diversity of species Can control succession (deflection - plagioclimax)

Question 32

Large scale timber production

Answer 32

Clear felling | Selective cutting

Question 33

Clear felling

Answer 33

Felling all the trees in one area destroying habitats on a large scale

Question 34

Drawbacks of clear felling

Answer 34

Decreases soil mineral level Leaves soil susceptible to erosion Takes 50-100 years of succession Trees bind soil Trees remove water from soil and stops it from being washed away Trees maintain nutrient levels through their roles in the carbon and nitrogen cycle (decomposition)

Question 35

Selective cutting

Answer 35

Only cutting down the largest, most valuable trees

Question 36

How is tree growth encouraged for selective cutting

Answer 36

Controlling pests and pathogens Only planting species where they will grow well Position tress at optimum distance to decrease comp

Question 37

Aims of sustainability

Answer 37

Preserve the environment Ensure resources are available for future generations Allow all humans to live comfortably Enable LEDCs to develop

Question 38

Modern sustainable forestry

Answer 38

Any tree harvested is replaced by another (naturally or planted) Forest must maintain its ecological function Local people must benefit from the forest

Question 39

Main principles of fisheries

Answer 39

Take place at a level that allows it to continue indefinitely (ideally carrying capacity and excess are harvested) Must maintain structure, productivity, function and diversity of the ecosystem Must adapt to changes in circumstances and comply w. local, national and international regulation

Question 40

Strategies put in place for fisheries

Answer 40

Large mesh sizes so only mature fish are caught Limiting recreational/ commercial fishing to certain times of the year EU common fisheries policy - Fishing quotas limiting no. of certain fish and where they can be caught

Question 41

Aquaculture

Answer 41

Farming fish Restricts impacts on oceanic fish value Allows susceptible fish species numbers to recover But decreases genetic biodiversity

Question 42

Why do fish numbers fall

Answer 42

Too few adult fish left to breed and maintain fish numbers

Question 43

Scramble competition

Answer 43

Relies on all individuals finding food and nest sites by chance this allows natural selection as some may be better adapted than others

Question 44

Dominance hierarchy

Answer 44

Strongest, most dominant individuals breed and pass on their alleles - if there's only 1 dominant individual there is likely to be less variation in the next gen.

Question 45

Why is preservation not enough to maintain biodiversity

Answer 45

Preservation only keeps the environment as it is If the ecosystem has already decreased preservation doesn't prevent further loss Takes active intervention

Question 46

Masai Mara region

Answer 46

National reserve in Kenya Combined needs for locals to run farms w/ larger land owner who use land to encourage conservation and generate income (ecotourism)

Question 47

Terai region

Answer 47

Home to Bengal Tiger (endangered) Forest is under pressure due to increased agriculture and grazing Comm forestry initiatives allow locals to exploit but also adopt responsibility Marketing products made for forests also generates income

Question 48

Peat bogs

Answer 48

Peat takes 1000's of years to accumulate Ideal for Sphagum moss - feeding and stopping off points for migrating birds Local level schemes aim to restore certain peat bogs and end commercial use

Question 49

Human activities affecting the Galapagos

Answer 49

Fishing and whaling have upset the marine ecosystem Intro of new species e.g. goats (eat vegetation), rodents (damage eggs of natives), dogs and cats (chase and eat native) Tourism Scientific research Increasing pop.

Question 50

Strategies to maintain the Galapagos

Answer 50

``` Searching boats for foreign species Using natural predators Culling feral goats Educating Captive breeding for tortoises Galapagos Marine Reserve ```

Question 51

Antartica

Answer 51

Overfishing of krill (keystone species) Moinitor catch size Whales protected by marine reseves Sea birds protected by night fishing and during the non-breeding seasons

Question 52

Measuring distribution

Answer 52

Line or belt transects (systematic sampling)

Question 53

Measuring plant abundance

Answer 53

Randomly placed quadrats | No. of individuals in sample / Area of sample

Question 54

Measuring animal abundance

Answer 54

Capture, mark, release, recapture (all occurs in orig. sample area) (no. in first sample * no in 2nd sample) / no. of recaptured marked individuals