chapter 24- populations and sustainability

Question 1

what are the phases of a population growth curve

Answer 1

1- lag phase
2- exponential growth phase
3- stationary phase

Question 2

describe phase 1/lag phase of a population growth curve

Answer 2

there is a small founder population (species new to an area) the birth rate is higher than the death rate, there is growth but its slow

Question 3

describe phase 2/exponential growth phase of a population growth curve

Answer 3

population reproduces at the max breeding rate, no constraints on pop increase, there is a constant doubling time

eg if it takes 2 yrs for a pop to increase from 15 to 30 individuals then in another 2 years it will increase from 30 to 60

Question 4

describe phase 3/stationary phase of a population growth curve

Answer 4

there is oscillations around a mean population size, br is approx equal to dr, mean pop size is the carrying capacity

Question 5

is there a stage 4 on a population growth curve and why

Answer 5

no, there is unlikely to be a death phase because the species would just emigrate to another habitat, this is possible because it isnt a closed culture

Question 6

what are abiotic factors and give egs

Answer 6

non living factors in an ecosystem

temp, light intensity, light quality, pH, wp of soil, availability of nest sites etc

Question 7

what are biotic factors and give egs

Answer 7

living factors in an organism

predation, disease, competition, migration, (em/imm)

Question 8

what does density dependent mean and give egs

Answer 8

factors that their effect gets stronger as population size decreases

eg if more animals then drought at the water hole???

most are biotic factors

Question 9

what does density independent mean and give egs

Answer 9

mostly abiotic factors

they have catastrophic effects on populations

eg earthquake, forest fire

Question 10

what is competition (b/ab)

Answer 10

it is a biotic factor, competition for the limited/finite resources in an ecosystem

Question 11

what is interspecific competition

Answer 11

between pops of different species, it reduces the level of resources for all species involved, results in smaller pops, better adapted species outcompete > elimination of less well adapted (the competitive exclusion principle

Question 12

what is intraspecific competition

Answer 12

competition between species of the same species

competition for the same resources eg breeding territory

leads to fluctuations in pop size

Question 13

What is ecosystem carrying capacity?

Answer 13

Ecosystem carrying capacity is the maximum population size an ecosystem can support.

Question 14

why would increased light supply cause a pop size to increase

Answer 14

Light is required for photosynthesis. As the rate of photosynthesis increases, plants grow faster and reproduce more quickly.

Question 15

Foxes are predators to rabbits.

How would an increase in the rabbit population affect the fox population?

exp

Answer 15

The fox population would increase and then decrease.

When a prey’s population size increases, there’s more food available to predators. So, the predator’s population size increases.

However, as a result of predation, the prey’s population size decreases. This means there’s less food available to the predators and so their population size decreases.

With fewer predators, the prey population size can increase, and the cycle continues.

on a graph, both oscillate laterally, with one ahead of the other

Question 16

what is conservation

Answer 16

the maintenance of biodiversity in ecosystems through human actions or management

Conservation is the active management of an ecosystem to maintain its species and habitats

it allows the use of natural resources to be used sustainably (sustainable development/take only what you need)

it allows the reclamation of damaged/destroyed ecosystems

it is a dynamic process that adapts to constant change

Question 17

what is preservation

Answer 17

the protection of an ecosystem by restricting or banning human activity so that the ecosystem is kept in its original state

it is often used for ecosystems that are ecologically, archaeologically or palaeontologically sensitive so they are easily damaged or destroyed

Question 18

What are the three reasons for carrying out conservation

Answer 18

Economic
social
ethical

Question 19

what are economic reasons for conservation

Answer 19

provide resources for humans, allows human survival from medicine, clothes, food, timber, paper, prevents soil erosion (if you get rid of roots then soil erodes away), genetic diversity for future products and cross breeding, high biodiversity protects against b+ab stresses

promotes ecotourism
drug development

Question 20

what are social reasons for conservation

Answer 20

beneficial to human health

enjoyment of natural beauty/provides activities with others

Question 21

ethical reasons for conservation

Answer 21

organisms have a right to exist, moral responsibility to future reasons, preservation of KEY STONE SPECIES

prevents extinction of endangered species, conserves biodiversity for future generations

Question 22

what are the aims of sustainable development

Answer 22

to conserve ecosystems, control future resource availability, healthy lives for humans, allow ledcs to develop, create an even balance between resource consumption between m/ledcs

Question 23

what 3 things does the sustainable management of forests and woodland allow

Answer 23

maintenance of biodiversity, timber supply, and the economic viability of timber production

Question 24

what are the 2 methods of small scale timber production

Answer 24

coppicing and pollarding

Question 25

what are the 2 methods of large scale timber production

Answer 25

planting and felling of trees in forests

Question 26

what is coppicing and why is it good for long term....

Answer 26

woodland management, cut tree trunk down to stump close to the ground, stimulating new shoots to grow and so can be felled again years later/harvested Coppicing keeps the tree alive which means the process can be repeated indefinitely

Question 27

3 benefits of coppicing

Answer 27

It increases the lifespan of trees. It creates a variety of light levels (This increases plant biodiversity) It grows new shoots more quickly than saplings (This increases timer production)

Question 28

a disadvantage of coppicing

Answer 28

Coppicing requires skilled workers to carry out the cutting and harvesting. As a result, it can be labour-intensive

Question 29

what is pollarding and why is it done

Answer 29

pruning the upper branches of a tree/cuts the trunk higher up than coppicing, promoting a dense head of foliage and branches new growth is out of reach of animals done for producing fodder to feed livestock (pruned at shorter intervals) and for wood (pruned at longer intervals producing longer poles that can be used for posts, fences etc)

Question 30

One method of timber production is clear felling. Clear felling involves…

Answer 30

removing most or all of the trees in a forest area.

Question 31

How do farmers ensure that clear felling is sustainable? (2 reasons)

Answer 31

Farmers limit the size of the felled area and they make sure that the felled trees are replanted. This limits soil erosion. They also keep a minimum distance between the replanted trees and allow them to fully regrow before the next cycle of clear felling.

Question 32

What is ecosystem management?

Answer 32

Ecosystem management is when humans manage an ecosystem’s natural resources.

Question 33

what is sustainability

Answer 33

When we make some natural resources available for use while protecting others

Question 34

benefit of sustainability

Answer 34

Sustainability allows us to use natural resources without them running out.

Question 35

State two examples of sustainable management.

Answer 35

timber production commercial fishing

Question 36

Fishing is sustainably managed through five measures, they are...

Answer 36

fishing quotas (limiting no of fish caught) regulating mesh sizes (catches are limited to adult fish) species restrictions (to help protect endangered fish) trawler sizes (is restricted to limit no of fish caught) catch inspections (by officials at ports to enforce protection measures) also local public awareness campaigns

Question 37

Why is it difficult to sustainably manage the fishing industry? 3

Answer 37

The areas open to fishing are very large (This makes it very hard to monitor catches) Catch inspections are very expensive (This can lead to a lack of enforcement of protection measures) Fishing companies falsely report the number of fish caught to avoid quotas.

Question 38

what are 2 environmental issues with commercial fishing

Answer 38

Large marine mammals get caught in nets and are killed. Fishing nets are often lost at sea.

Question 39

what are the concerns with fishing

Answer 39

overfishing > loss of signif potential yield, changes will occur in the trophic balance or in the food webs "fishing down the food web"

Question 40

what are the 2 ecosystem management examples i need to know

Answer 40

the masai mara region in kenya terai region in nepal peat bogs

Question 41

describe the ecosystem management for farming in the masai mara

Answer 41

grazing is limited to the edges of the reserve and the masai arent allowed in, larger masai populations are now established at the edges of the reserve > more grazing and removal of trees > soil erosion increased cultivation of the soil for crops > removal of native vegetation > reliance on artificial fertilisers

Question 42

describe the ecosystem management for ecotourism in the masai mara

Answer 42

main source of income for the reserve, sustainable tourism with 3 principles: no exploitation of reserve or locals, engagement with locals about development, infrastructure development benefits both tourists and locals.

Question 43

describe the ecosystem management for conservation and research in the masai mara

Answer 43

conservation of endangered species, big animals have declined, the higher the pop density > incr livestock grazing and incr in poaching. black rhinos are guarded 24/7, they are poached for their keratin horn 75% loss for giraffes, 80% warthogs } study done by WWF

Question 44

what is in the terai region of nepals and what is the overall problem

Answer 44

rich agriculture, well watered flood plains, tall grasslands, scrub, sal native tree forests, clay rich swamps agricultural and industrial economic activity, high pop density > over use of natural resources

Question 45

describe the ecosystem management for the ecosystem/what has happened in terms of, in the terai region of nepal

Answer 45

there are species eg bengal tiger, sloth bear, indian rhino, high biodiversity, tourism for local econ, deforestation to grow crops/timber mainly due to poverty and local gov corruption deforestation > greater effects from monsoon flooding

Question 46

describe the ecosystem management for sustainable forest management in the terai region of nepal

Answer 46

national legislation, harvesting rules, fixed prices, surplus income spent at local level >>>> better soil and water management incr in prices for forest products > greater income/employment secured biodiversity sustainable wood fuel sources

Question 47

what are the ecosystem of peat bogs

Answer 47

wet spongy ground that contains decomposing vegetation, a carbon sink peat forms when decomposing vegetation is prevented from full decomposition, the conditions are anaerobic and acidic so no bacteria, non aerobic decay there are mosses, cotton, heathers high biodiveristy with distinctive animals, fungal and plant species, often undisturbed by humans

Question 48

describe the ecosystem management for the loss of the ecosystem in peat bogs

Answer 48

now rare and threatened, decline due to reforestation, peat extraction, land drainage, increased agriculture, conservation needs to happen to allow flood management, reduce soil erosion and greater carbon sink use water conservation is centred around: not disturbing bog surface > trapping water in bog, removing tree seedlings, controlled grazing to promote biodiversity board walks!!

Question 49

what is the ecosystem of the galapagos islands

Answer 49

an archipelago of volcanic islands, special intrest because they have never been connected to the mainland, all species have adapted and are unique

Question 50

what are the plant and animals species of the galapagos islands

Answer 50

giant tortoise, marine iguana, mangrove, mosses, cacti

Question 51

what is the control of human species on the galapagos

Answer 51

national park, park rangers, limited acess, control of migrations, strict control of introduced species

Question 52

antarctica

Answer 52

all endotherms have blubber, plants only grow in ice free regions lichen and mosses, too cold for human settlement, waste and sewage into sea, been affected by global warming

Question 53

what are the environmentally sensitive ecosystems

Answer 53

galapogas islands antartica lake district snowdonia national park