Chapter 34 - Populations

Question 1

Name and explain 4 factors which affect population growth

Answer 1

• Food supply
  An increase in population size could cause competition for food
• Predation
  If prey is plentiful, predators will increase
• Diseases
  More diseases reduce population numbers
• Size of ecosystem
  The larger the area, the larger the population can grow

Question 2

Name two population growth forms

Answer 2

• J-shaped no limiting facts

- S-shaped limiting factors present

Question 3

Name the three phases in a sigmoid curve

Answer 3

• Lag
• Log
• Stationary

Question 4

Describe the lag phase

Answer 4

• Slow growing phase
• Individuals adapt and acclimatise to their environment
• Shortage of reproductive individuals
• Breeding partners do not meet
• Seek out new breeding partners

Question 5

Describe the log phase

Answer 5

• Rapid rise in population size
• Plenty of food and no competition
• Conditions are favourable
• Absence of predators
• Birth and immigration rates exceeds mortality and emigration rates

Question 6

Describe the stationary phase

Answer 6

• Growth rate becomes stable and constant
• Diseases spread faster
• Predators can hunt more successfully
• Resources become scarce, increases competition
• Maximum population that the environment can support

Question 7

Name five reasons for which less infections diseases occur

Answer 7

• Sewage treatment (dysentry)
• Hygenic handling of food
• General standards in cleanliness
• Immunisation
• Antibiotics

Question 8

Name two limiting factors which has been reduced in the human population

Answer 8

• Infectious diseases

- Shortage of food

Question 9

Explain why there is an increase in food production

Answer 9

• More land has been brought under cultivation
• Agriculture is more efficient due to modern technology
• Fertilisers increase crop yield
• Pesticides can prevent crops from being destroyed

Question 10

Name six social implications of the current human population growth

Answer 10

• Famine, war and diseases may increase the death rate
• More pollution and overcrowding
• More unemployment
• Less land will be availible for agriculture
• Global warming
• Increase in global demand for water