6.3.2 - Populations and Sustainability

Question 1

What is carrying capacity?

Answer 1

The maximum population size that can be indefinitely supported by an environment

Question 2

What is a limiting factor (populations)?

Answer 2

An environmental resource or constraint that limits population growth

Question 3

Why can’t population growth be sustained indefinitely?

Answer 3

There are many biotic and abiotic limiting factors that prevent every individual in a population from reaching adulthood and reproducing

This ensures the size of each species os limited at some point (ie carrying capacity is reached)

Question 4

What is a population growth curve?

Answer 4

Shows growth of a new population over time

Most natural populations will show the same characteristics

3 main stages:

1) slow growth (lag phase)
2) rapid growth (log phase)
3) stable state (stationary phase)

Question 5

What is slow growth (lag phase)?

Answer 5

• small population that are reproducing
• not a significant increase due to small population
• birth rate higher than death rate
• population adjusting to new conditions

Question 6

What is raid growth (log phase)?

Answer 6

• as number of breeding individuals increases, total population multiplies exponentially
• no constraints acting to limit the population explosion

Question 7

What is the stationary phase?

Answer 7

• further population growth prevented by external constraints (limiting factors)
• population size fluctuates but remains relatively stable
• birth and death rate approximately equal

Question 8

What are abiotic limiting factors (populations)?

Answer 8

Non-living components of the environment that affect the population size

Eg
• temperature
• light
• pH
• availability of water/oxygen
•humidity

Question 9

What are biotic limiting factors (populations)?

Answer 9

Limiting factors caused by living part of an ecosystem and interactions between organisms

Eg
• predation
• competition
•diseases caused by microorganisms

Question 10

What is immigration?

Answer 10

The movement of individuals into an area

Increases population size

Question 11

What is emigration?

Answer 11

The movement of individuals away from an area

Decreases population size

Question 12

What are density independent factors?

Answer 12

• have an impact on whole population regardless of size
• can dramatically change population sizes
• eg earthquakes, fore’s, volcanic eruptions, storms

Question 13

What are some examples of how ecosystems are managed to balance the conflict between conservation/preservation and human needs?

Answer 13

• Masai Mara region of Kenya
• Terai region of Nepal
• Peat bogs

Question 14

How is the Masai Mara National Reserve (MMNR) of Kenya being managed to reduce the conflict between conservation/preservation and human needs?

Answer 14

Large area of grassland home to huge populations of wildebeest, zebra etc

CONFLICTS:
• Masai ppl traditionally earn living by raising livestock, but overgrazing by livestock can destroy grassland
•poaching allows them to earn living but lowers animal population numbers
• elephants trample on crops

SOLUTIONS:
• Conservation trusts are working with ppl so they can earn from land through conservation + ecotourism and farm in a sustainable way
• legal hunting of overpopulated species allowed at certain times, park rangers employed and provided with equipment
• farmland fenced off to prevent elephants

Economic needs of people are met while allowing area to be conserved

Question 15

How is the Terai region of Nepal being managed to reduce the conflict between conservation/preservation and human needs?

Answer 15

Area of forest and grasslands. Variety of plants/animals there, including endangered bengal tiger. Almost 7 million people live and depend on forests resources to survive

CONFLICTS:
• forest being cut for resources (eg wood for fuel), destroying habitat
• forest being cleared to make space for houses, bringing humans and animals closer and causing conflict (eg tigers can kill livestock, but may be shot and killed themselves)

SOLUTIONS:
• increased retail price of forestry products, so greater economic input
•sustainable fuel sources to prevent overuse of wood
•employment in forest protection and production of non-timber products
• growth of nitrogen-fixing crop and using manure to enhance soil fertility
• promoting production of fruits and veg in hills to avoid further deforestation
• using genetic engineering to grow crops resistant to soil, climatic and biotic challeng

Question 16

How are UK peat bogs being managed to reduce the conflict between conservation/preservation and human needs?

Answer 16

Peat bogs are areas of wet peat that store water and CO2. Take thousands of years to form. They are home to lots of different plants and animals

CONFLICT:
Used to graze sheep and dear, but overgrazing causes:
•loss of moss species
• soil compaction, increasing water runoff and taking sediment with it
• general peat bog erosion

SOLUTION:
• gov funded programs eg Environmental Stewardship Scheme give farmers money to use peat bogs in sustainable way eg reduce livestock grazing
• no large trees planted nearby - they will remove the water

Question 17

What are environmentally sensitive ecosystems?

Answer 17

Ecosystems that are less resistant to change than others

Question 18

What kind of management techniques can be used in environmentally sensitive areaS?

Answer 18

• limiting areas tourists can visit
• controlling the movement of livestock
• introducing anti-poaching measures
• replanting of forests and native plants
• limiting hunting through quotas and seasonal bans

Question 19

What are the effects of human activities on the Galápagos Islands?

Answer 19

Non-native animals and plants have been introduced, which compete with native species

This decreased the native population

Question 20

What methods of control have been introduced in the Galápagos Islands?

Answer 20

• Galapagos national park established in 1959
• introduction of Park rangers across the iPads
• controlling migration to/from islands
• strict controls over movement of introduced animals
• limiting number of tourists

Question 21

What are the effects of human activities on Antarctica?

Answer 21

• visitors have caused pollution by dumping sewage in sea and leaving rubbish
• shipping accidents led to oil spills, which severely affect wildlife
• hunting, whaling and fishing have reduced wildlife populations in the area
• global warming has led to ice melting

Question 22

What is the Antarctic treaty?

Answer 22

Established 1961 to protect Antarctica. Provisions include:
• scientific cooperation between nations
• protection of Antarctic environment
• conservation of plants and animals
• designation and management of protected areas
•management of tourism

Question 23

What are the effects of human activities on the Lake District and Snowdonia?

Answer 23

Many visitors go walking, leading to the erosion of foot paths and loss of soil from hillsides

Soil that ends up in waterways/lakes can affect pH, causing knock-on effects for wildlife

As paths become harder to walk on, people can start to trample and destroy sensitive vegetation other side of paths

Question 24

What are the key purposes of the park authority for Snowdonia national Park?

Answer 24

Conserve and enhance the natural beauty, wildlife and cultural heritage of the area

Promote opportunities for the understanding and enjoyment of the special qualities of the park

Enhance the economic and social well-being of communities within the park

Question 25

What does the Lake District National Park Authority do?

Answer 25

Like Snowdonia - conserves the region while enabling access for millions of visitors each year Aactive management of the countryside (eg replanting native tree species)

Question 26

Why do prey/predator numbers fluctuate?

Answer 26

STAGE 1 • increase in prey population provides more food for predators • more predators survive + reproduce, so greater predator population STAGE 2 • increasing predator pop eats more prey, causing decline in prey population • prey death rate > birth rate STAGE 3 • larger predator pop not supported by declining prey numbers • intraspecific competition increases • decrease in predator population STAGE 4 • reduced predator numbers result in less of the prey pop being killed • more prey will survive and reproduce, increasing prey population This cycle repeats

Question 27

What is intraspecific competition?

Answer 27

Between members of the same species • Availability of the resource determines population size

Question 28

What is interspecific competition?

Answer 28

Between different species Results in a reduction of the resource available to both populations

Question 29

Outline the interspecific competition between grey and red squirrels

Answer 29

Red squirrel = native Grey squirrel = invasive Grey outcompeted red • eats wider range of food • larger so can store more fat As grey pop increased, food supply for red decreases more

Question 30

What is a niche?

Answer 30

It’s role in the community

Question 31

What is the competitive exclusion principle?

Answer 31

No two species can occupy the same niche indefinitely when resources are limiting When 2 species are competing for the same food source but one is better adapted, the less well adapted is likely to be outcompeted

Question 32

Why does intraspecific competition result in fluctuations in population size?

Answer 32

1) if the resource is plentiful, all organisms have enough to survive and reproduce. Population increases 2) increased population means resources are now limited. Not enough of the resource is available to support population. Population decreases - intraspecific competition 3) less organisms in the smaller population. More organism can survive and reproduce and reproduce, causing the population to increase

Question 33

What is conservation?

Answer 33

The maintenance of biodiversity though human action or management

Question 34

What is preservation?

Answer 34

Protection of an area by restricting or banning human use (ecosystem is kept exactly as it is)

Question 35

What is the importance of conservation?

Answer 35

ECONOMIC • provides resources humans need to survive and to provide income • medicines, timber, clothes, food • ecotourism SOCIAL • people enjoy the natural beauty of wild ecosystems • used for activities for health (relaxation and exercise) - walking, running, birdwatching etc ETHICAL • all organisms have a right to exist and most play an important role within their ecosystem • have a moral responsibility for future generations to conserve wide variety of ecosystems

Question 36

What is a sustainable resource?

Answer 36

Renewable resource rage s being economically exploited in a way that it wont diminish or run out

Question 37

What are the aims of sustainability?

Answer 37

* preserve the environment * ensure resources are available for the future generations *  allow humans in all societies to live comfortably *  enable less economically developed countries (LEDCs) to develop through exploiting their natural resources * create a more even balance in the consumption of these resources between more economically developed countries (MEDCs) and LEDCs

Question 38

How can timber production be made sustainable on a small scale?

Answer 38

COPPICING • tree trunk cut close to the ground • new shoots form from the cut surface and mature • eventually these shoots are cut again and the cycle repeats • rotational coppicing - divide woodland into sections and coppice on at a time POLLARDING • similar to coppicing • trunk is cut higher up • deer and other animals can’t eat new shoots

Question 39

How can timber production be made sustainable on a large scale?

Answer 39

Large scale based on felling large areas of forest - trees wont regrow Ensure sustainability: • selective cutting (removing the largest trees only) • replace trees through replanting (natural regeneration takes too long) • plant trees at an optimal distance (reduce competition) • manage pests/pathogens (increase yield) • areas o forest remain for indigenous people

Question 40

How can fishing be made sustainable?

Answer 40

INTERNATIONAL AGREEMENTS • common fisheries policy in EU • fishing quotas • aim to maintain natural population of species • fish can reproduce sufficiently to maintain population size NETS AND MESH SIZES • large enough so small, immature fish can escape • allow breeding of populations to continue FISHING AT CERTAIN TIMES OF THE YEAR • protect breeding season, allowing numbers to increase to sustainable level FISH FARMING • maintain supply while preventing loss of wild species