Population Size✅

Question 1

What is carrying capacity

Answer 1

The max size of a population

Question 2

Describe a typical population growth curve

Answer 2

Slow growth (lag phase)
Rapid growth
Stable state (carry capacity) birth and death rate similar

Question 3

What is definition and example of density dependent factors

Answer 3

The impacts of these factors vary with population density
Eg abiotic: temp, water availability, ph, light intensity, BIOTIC: predation, disease, competition, migration

Question 4

Give definition and example of density independent factors

Answer 4

Factors that affect a population regardless of its size
Eg natural events (earthquakes, storms)

Question 5

What is a limiting factor in context of populations

Answer 5

Factor that restricts the final size of a population

Question 6

What is interspecific competition

Answer 6

Different species competing for resources, the competing species overlap in food sources, behavior or habitat they occupy
Better adapted species may outcompete other species if resources are limited

Question 7

What is intraspecific competition

Answer 7

Members of same species competing for limited resources

Question 8

What is conservation and what happens

Answer 8

The sustainable management of an ecosystem to maintain biodiversity.
Active, sustainable management (balancing maintenance of biodiversity with extraction of resources). Can Include reclamation (restoring damaged ecosystems)

Question 9

What is preservation and what happens

Answer 9

Maintenance of ecosystems in their original state (without interference)
Ecosystems monitored, visitors not allowed, interference kept to a minimum

Question 10

What are ethical, economical, social benefits of conserving ecosystems

Answer 10

Ethical: humans have moral responsibility

Social: aesthetically attractive, provide recreation, enable ecotourism, have educational benefit

Economic: organism harvested using sustainable approach, humans gain resources (food,drugs, timber),

Question 11

Define sustainability

Answer 11

Use of natural resource without damaging biodiversity and ensuring that resource is not depleted

Question 12

How is timber production done sustainably

Answer 12

Coppicing (tress getting cut close to ground and produce new shoots), can be rotational (region varies each year), trees are replanted

Question 13

How is fishing done sustainably

Answer 13

Fishing quotas, fish farms

Question 14

Give description of masai Mara and conservation methods

Answer 14

Savannah ecosystem, contains grassland and woodland, large populations of zebra buffalo elephants lion leopards

Promotion of ecotourism, prevention of rhino poaching, legal hunting

Question 15

Give description of Terrai region and conservation methods

Answer 15

High temps+humidity in summer, fertile soils with lush forest, high biodiversity, heavy deforestation+agriculture use

Sustainable forest management, improved irrigation schemes (increase efficiency of agriculture production), encouragement of fruit+veg growing in nearby regions to relieve pressure of intensive farming on region

Question 16

Give description of peat bogs and conservation methods

Answer 16

Ground with high water content+decomposing vegetation, natural stores of CO2,peat can be removed for use as a fuel to improve farm soils, contains rare species

Blocking ditches to prevent flooding, this raises water levels of peat bogs, removal of trees and prevention of afforestation

Question 17

Description of Galápagos Islands and conservation methods

Answer 17

An environmentally sensitive ecosystem, contains unique

Limiting and managing tourism, strict controls over movement of introduced

Question 18

define A: limiting factor, B: a density dependant factor (2 marks)

Answer 18

A: a factor that limits the maximum size of a population

B: a factor that affects population size, but its effects vary with population density

Question 19

state 3 factors for which plant species are likely to compete (3 marks)

Answer 19

light
water (from the soil)
CO2
(named) mineral ions (from soil)

Question 20

Corals, limpets and anemones are all filter feeders ( they strain food particles from water) with habitats on the ocean floor. Barnacles are filter feeders that have evolved the ability to form colonies on skin of whales and side of ships. Explain the benefit of barnacles of this ability (3 marks)

Answer 20

the filter feeders have the same ecological niche

they feed on similar food items

barnacles avoid competition

the competition is interspecific

Question 21

describe the difference between conservation and preservation (2 marks)

Answer 21

conservation is active/manages an ecosystem/ requires interference

Question 22

Tilapia fish are primary consumers. Salmon are tertiary consumers. Explain why the farming of tilapia is more sustainable then farming of salmon (2 marks)

Answer 22

Tilapia are lower down the food chain

Only a single energy transfer occurs (from producer to primary consumer)

Farming salmon requires depletion of wild (primary/secondary) fish populations to act as food for the salmon

Question 23

suggest why reclamation of a habitat is difficult (2 marks)

Answer 23

sometimes it is unclear which species were present in the original community

understanding and restoring the original abiotic conditions may be difficult

succession takes a long time

Question 24

describe what is meant by an environmentally sensitive ecosystem (1 mark)

Answer 24

an ecosystem that is especially vulnerable to environmental change/human interference

Question 25

suggest why both conservation and preservation of peat bogs is difficult to achieve (3 marks)

Answer 25

preservation is usually impossible because so few peat bogs remain in there original state

peat bogs take a long time to form

there is a conflict between reclamation/ conservation and human activity (eg extraction of peat)