24.1 Popn. Size

Question 1

What are the 3 phases on a population growth curve graph

Answer 1

phase 1 - slow growth
phase 2 - rapid growth
phase 3 - stable state

Question 2

what’s the carrying capacity in a population growth curve

Answer 2

the max. population size of a biological species that can be sustained in an environment, given that food, water and other resources are available

Question 3

What are the phases of a population growth curve in yeast in a flask

Answer 3

1. lag phase - little growth while yeast transcribes genes/synthesises enzymes for the right conditions
2. rapid growth phase - rapid exponential growth; no limiting factors since relatively low density
3. table state - slow growth rate due to accumulation of toxic waste products (e.g. ethanol) or lack of sugars

Question 4

What are the phases of a population growth curve in rabbits in a field

Answer 4

1. lag phase - little growth due to small population; long gestation, individuals rarely meet so less mating.
2. rapid growth rate - rapid growth though not exponential; few limiting factors
3. stable state - slow growth due to intraspecific competition for food/resources/predation etc.

Question 5

what are limiting factors

Answer 5

can be biotic and abiotic; migration, also affects popn. size (immigration, emigration)

Question 6

what are density independent factors

Answer 6

factors that will affect the popn. regardless of its size (fires, storms, volcano eruptions, earthquakes)

Question 7

what are natural limiting factors

Answer 7

when talking about human population growth; economic conditions, cultural backgrounds, religious backgrounds.
factors also affect death rates including age profile, quality medial care, food availability, natural disasters, war etc