6.6 populations and sustainability

Question 1

what is the carrying capacity

Answer 1

the maximum population size that can be maintained over a period in a particular habitat

Question 2

define limiting factor

Answer 2

the factor whose magnitude slows down the rate of reproduction

Question 3

explain the shape of the population size graph

Answer 3

lag phase - only a few individuals, acclimatising to their habitiat, rate of reproducution is slow
log phase - reproduction is quicker, population size increases rapidly
stationary phase - population size has levelled out at the carrying capacity

Question 4

name the types of strategists

Answer 4

r - strategies
k - strategies

Question 5

explain what K strategists are

Answer 5

species whose population size is determined by the carrying capacity
limiting factors exert a more significant effect
- low reproduction rate, development, late reproductive age, long lifespan, large body mass

Question 6

explain r - strategists

Answer 6

population size increases so quickly it exceeds the carrying capacity of the habitat before the limiting factors have an effect
- high reproductive rate, quick development, young reproductive age, short life span, small body mass

Question 7

what abiotic factors affect population size

Answer 7

light availability
water supply
water mineral content
temperature
space availability
soil pH

Question 8

what biotic factorsaffect population size

Answer 8

interspecific competition
intraspecific competition
predation

Question 9

what is interspecific competition

Answer 9

competition for the same resources from different species

Question 10

what is intraspecific competition

Answer 10

competition for the same resources between different members of the same species

Question 11

explain the relationship between predators and prey

Answer 11

predator population increases more prey is eaten
prey population reduces and leaves less food for the predators
fewer predators survive = population reduces

Question 12

describe the effects of competition

Answer 12

competitive exclusion - occupy similar niches, better adapted species out compete the others
resource partitioning - resource is divided up to satisfy all their needs
character displacement - species with similar niches differentiate to avoid competitive exclusion

Question 13

what is conservation

Answer 13

maintainance of biodiversity, involves active management from humans, human intervention

Question 14

what is preservation

Answer 14

Leaving ecosystems/ habitats I disturbed

Question 15

explain different threats to biodiversity

Answer 15

increasing human population
over exploitation of wild populations for food
habitat disruption and fragmentation
invasive species introduced

Question 16

reasons for conserving biological resources

Answer 16

moral obligation
important natural resources
supply of food
economic benefits
responsibility

Question 17

ecological/environmental reasons for maintaining biodiversity

Answer 17

better ability to adapt to environmental changes or threats
keystone species
essential environmental services they provide plants absorb C02
microorganisms break down organic waste
water cycle
nutrient cycle
direct and indirect energy source

Question 18

aesthetic reasons for maintaining biodiversity

Answer 18

joy and pleasure in the beauty of nature
inspiration

Question 19

ethical reasons for maintaining biodiversity

Answer 19

moral obligation
no right to cause the extinction of other species
environments may be lost if they are not conserved

Question 20

social reasons for maintaining biodiversity

Answer 20

enjoyment
activities people can do together

Question 21

what is sustainability

Answer 21

the ability of an ecosystem to maintain its biodiversity whilst providing humans with the resources

Question 22

examples of managed ecosystems

Answer 22

commercial fishing
timber production

Question 23

explain how commercial fishing is being managed

Answer 23

fishing quotas - not overfishing
regulating mesh size of nets
area where fishing is banned
limit the size of the fish fleet
inspecting the catch
banning certain practices

Question 24

explain how timber production is being managed

Answer 24

coppicing
Clear felling

Question 25

why does conflict exist between conservation and human needs

Answer 25

use resources such as land, water, wood and fossil fuels as the human population increases = need for resources increases harmful effect on the environment

Question 26

explain how change in food demand is causing conflict

Answer 26

need to produce higher yields in crops = modern farming practices took over - monoculture - cereal crops - hedgerows removed - land drained, ponds filled - use of pesticides and fertilisers increased

Question 27

how is farming being made more sustainable

Answer 27

areas have been rewilded organic farming re-establishing hedgerows planting wildflower field margins

Question 28

impacts of humans on the environment

Answer 28

climate change/ burning fossil fuels introduction of species hunting degradation/ loss of habitats

Question 29

explain how burning of fossil fuels can affect plant and animal populations

Answer 29

large increase in carbon dioxide levels higher average global temperatures, changes in weather, melting ice caps, flooding, rising ocean acidity etc habitats have changed

Question 30

explain how the introduction of species is impacting the plant and animal populations

Answer 30

invasive species may have no natural competitors, predators or pathogens populations can grow rapidly negatively affect native species outcompete local species

Question 31

explain how hunting is impacting animal and plant populations

Answer 31

extinction may result must be carried out sustainably to prevent extinction

Question 32

explain how habitat loss can impact animal and plant populations

Answer 32

habitats removed puts species at risk species have to search for other habitats and compete for the rest

Question 33

how can the effects of humans be controlled

Answer 33

preventing import and export of species restrictions put in place - certain areas restricted, policies reducing sources of greenhouse gases increasing the capacity of sinks