6.3.2 populations and sustainability

Question 1

explain the growth curve

Answer 1

• lag phase = slow growth
• log phase = fast growth + reproduction
• stationary - death rate = birth rate
• death rate bcs nutrients run out –> carrying capacity

Question 2

limiting factor definition for population growth

Answer 2

environmental factors that restrict population growth

Question 3

types of limiting factors

Answer 3

• density-dependent factors
• density independent factors

Question 4

examples of density dependent factors

Answer 4

• factors that differ depending on the density of the population size
• competition - inc bcs they compete for limited resources = more deaths less birth rate
• predation - predators can locate prey more easily in a densely packed area inc death rate
• disease - spreads more easily in densely packed pop so death rate inc

Question 5

examples of density independent factors

Answer 5

• factors that affect pop size regardless of size
• natural disasters
• climate change

Question 6

carrying capacity definition

Answer 6

the max population size an environment can have if resources are available

Question 7

how does resource availability impact the population

Answer 7

• if theres lots of resources = population increases
• if theres little = population stabilizes or declines

Question 8

predator-prey relationship

Answer 8

• inc prey pop. = more food for predators –> predator pop inc
• inc in predator pop = more prey gets eaten –> prey pop dec
• dec in prey pop = less food for predator –> predator pop dec
• predator pop dec = less prey eaten –> prey pop inc
• repeats

Question 9

describe effect of intraspecific competition

Answer 9

• resources in excess - enough for all to survive and reproduce
• at a bigger pop size - resources decrease and there is not enough for all to survive and reproduce - natural selection
• more resources become available again so enough for all

Question 10

describe effect of interspecific competition

Answer 10

• between other species
• compete for same resources
• leads to competitive exclusion - one species outcompetes the other because it is better adapted

Question 11

define conservation

Answer 11

• active management using human intervention
• in-situ or ex-situ

Question 12

define preservation

Answer 12

• maintaining habitats in their present state without human intervention
• national parks

Question 13

explain coppicing (small-scale)

Answer 13

• when trees are cut at the base
• new shoots can grow
• continuous and renewable source of timber
• tall trees dont block the sunlight for smaller trees so they can photosyntheis

Question 14

explain pollarding (small-scale)

Answer 14

• tree is cut higher up
• prevents grazing of animals eating new shoots
• common in places with animals around

Question 15

advantages of coppicing and pollarding

Answer 15

• creates habitats
• long-term timber supply

Question 16

large scale methods of timber production

Answer 16

• clear cutting/felling large areas
• selective cutting - remove only large trees
• replant trees at optimal distances- reduces competition for abiotic factors - higher yield of timber
• manage pathogens and pests

Question 17

describe aquaculture

Answer 17

• fish farming
• breeding and harvesting of fish in controlled environments like oceans

Question 18

why is aquaculture sustainable

Answer 18

• fishing quotas: limits on the number of certain species of fish that allowed to be caught in a particular area. –> avoid overfishhing
• use big net mesh so only immature fish can escape and mature fish are caught to continue breeding
• restrict the time of year to fish - protect breeding season
• fish farming - maintain supply of protein food and prevent loss of wild species

Question 19

disadvantages of aquaculture

Answer 19

• disease outbreak
• pollution from uneaten fish food
• farmed fish can escape and compete with native species

Question 20

human impact on ecosystems

Answer 20

• Deforestation
• Overfishing
• Pollution
• Climate Change

Question 21

CBD, CSS, Rio convention

Answer 21

• CBD - promote sustainable use of natural resources
• CSS - provides funding to farmers for conservation
• Rio convention - promoting global environmental protection efforts

Question 22

other factors that affect pop size

Answer 22

• immigration and emigration

Question 23

aim of conservation

Answer 23

• sustainable development - have enough resources for future development
• maintain biodiversity - species, genetic and habitat

Question 24

why is conservation important

Answer 24

• economic - resources for money + tourism
• social - enjoyment
• ethical - right to exist

Question 25

aim of preservation

Answer 25

protect environmentally sensitive ecosystems - galapagos islands and antarctica bcs they have a unique biodiversity - maintain biodiversity

Question 26

describe what is sustainability and its usefulness

Answer 26

- ensure there is enough resources for future generations - enable less economically developed countries to develop - balance consumption of resources between more and less economically developed countries - preservation