Yr 13- Chapter 24 - Population and Sustainability

Question 1

There was some management activities which were planned in a peat bog
planting of small conifer trees
construction of ditch
managed burning
suggest improvements that could be made to these plans to help conserve peat bog ecosystem

Answer 1

Plant less conifer trees as planting of more trees removes water from the bog
There should not be a construction of a ditch as a ditch drains water from the bog
There should be less burning as this can cause potential death of species; rare species. This increases rate of extinction

Question 2

Explain why the preservation of peat bog ecosystem is not a strategy that can be used in most cases

Answer 2

Many peat bogs have already been damaged and preserving or restoring peat bogs can cost a large sum of money
Preservation means leaving the ecosystem untouched, but this is not the case in many situations

Question 3

Suggest two measures that a treaty might impose, to prevent fishing from causing permanent damage to the ocean.
identify practical difficulties to these measures

Answer 3

1. Put fishing quotas in place
   D - false reporting of fish caughtt and surveillance of fishing can be difficult
2. Use a larger mesh (different size)
   D- Expensive to produce new mesh nets, and area of ocean is too large to put this in place

Question 4

What are the arguments for and against harvesting kill instead of larger fish as a human food source

Answer 4

For - 100x more energy is given from krill than larger fish
Against - Harvesting krill could impact the ecosystem and could also require a change to the fishing industry

Question 5

Explain why the introduction of wolves to Yellowstone Park in 1995 is an example of conservation

Answer 5

Introduction of wolves is conservation because one is maintaining biodiversity and helps the global wolf population so does not become extinct

Question 6

Describe the differences between the following biological terms:
Conservation and preservation

Answer 6

Conservation is maintaining the ecosystem, it involves active management of the habitat.
Preservation is leaving the habitats undisturbed and no human interference

Question 7

Beavers are considered to be keystone species
Explain why they are keystone species in their native Canada

Answer 7

They have a significant effect in the ecosystem
Lots of other species rely on beavers

Question 8

Explain how the following activities could have contributed to increased habitat diversity
1. Constructed dams
2. Felled trees
3. Built lodges

Answer 8

1. Constructed dams - reduces flooding downstream and flow of water decreased so more aquatic species are present
2. Felled trees - more light reaches ground level plants
3. Built lodges - creates shelter/habitat for species

Question 9

Suggest one other benefit of the reintroduction of beavers

Answer 9

Scientific study can be conducted
More education can be given to the population

Question 10

Conservationatists have been working with local people to promote sustainable use of resources
Explain why the Madidi National Park is an example of conservation rather than preservation

Answer 10

Madidi National Park is an example of conservation because there are local people in the area who are trying to conserve biodiversity by promoting sustainable use of resources. It is not preservation because then the park would be left untouched.

Question 11

Timber can be produced economically by a technique called clear felling. Clear felling can damage biodiversity.
Explain how it is possible to produce timber sustainability using clear felling

Answer 11

Replant trees that have been felled
Limit the size of area that is felled

Question 12

Suggest why data of elk being shot is accurate but the method used to obtain the data is not a valid way

Answer 12

Data of elk being shot is accurate because the number is recorded.
The method is not valid because elk being shot depends on population size (independent factor).

Question 13

Suggest how an ancestral species might have evolved into the two different species. E.g. B pratorum and B terrestris

Answer 13

Both might have evolved into 2 different species due to isolation.

In addition there is a seasonal difference in breeding, for example the peak number of workers in B pratorum is June whereas the peak for B terrestris is July.

Species may end up feeding on different types of flowers.

Question 14

Describe the pattern of growth of the yeast population

Answer 14

Initially (day 0 to 1) it was lag phase as the percentage was increasing slowly.
From day 1 to 3 there is a log phase as the percentage of final population rapidly increases (steep gradient)
At day 3 and 4 the rate of increase becomes less steep and by day 4 to 6 the growth has become stationary and population levels off.
The initial population was 24 and final was 100, so there is a 76% increase.

Question 15

Explain why ethanol is considered to be a primary metabolite of yeast

Answer 15

Ethanol is produced in all yeast growth phases

Question 16

Outline how two factors may limit the maximum size of the yeast population

Answer 16

If sugar concentration is too low
If pH falls too low than it limits

Question 17

A traditional timber production process that is still used in parts of the Lake District is coppicing
Describe the process of coppicing and explain the potential benefits of coppicing to the biodiversity of a woodland (6)

Answer 17

Coppicing is when the tree is cut until the trunk is very close to the ground.
Then several new shoots grow from the cut surface
The young shoots are protected from grazers. This process is repeated after a given time and can be repeated forever.

The benefits of coppicing is that new stems grow more rapidly.
The lifespan is extended
As trees are cut down more frequently, more light is given for smaller plants aswell.
This provides a variety of habitats and the longer lifespan of trees may mean animals are surviving for longer.

Question 18

Increasing habitat diversity may lead to an increase in species and genetic diversity .
Explain why

Answer 18

Species diversity will rise as more species live in the new habitats
Genetic diversity will increase as species have a wider range of conditions in which to live

Question 19

With reference discuss the factors that may have affected the size of elk population
before 1995
after 1995
(6)

Answer 19

Population size is affected by limiting factores
Before 1995, the elk population steadily increases as there is not many limiting factors such as competition of food. During this time, there was enough food for the elk to survive on, as well as less frequent hunting for elks so population was higher.

Before 1995, the population eventually levels off as it reaches it carrying capacity, however it is noticeable that before 1995 (during 1994) there starts to be a decrease in population this can be due to intraspecfic or interspecific competition.

In addition throughout the graph there are several dips (e.g. 1990-1992) this may be due to environmental factors such as natural disaster.

After 1995, grey wolves have been reintroduced and this has caused a decline in elk population therefore could possibly indicate that wolves introduction lowers elk population however the data is somewhat unreliable as 1996 and 1997 does not have data so difficult to form conclusions

Question 20

Explain why population of penguins might increase from 1976 to 2010

Answer 20

Increase in food availability
less competition