12: population ecology

Question 1

Biotic potential

Answer 1

How quickly a species can reproduce solely based on physiological limits

Question 2

Density-dependent factors

Answer 2

Disease transmission
Food shortage
Higher predation rates
Environmental degradation

Question 3

Types of competition between species & result

Answer 3

Interference - fighting for shared resources
Exploitative - consuming shared resources

Results in:
Competitive exclusion - elimination of 1 species
Resource partitioning - species adapt to use niches differently

Question 4

Batesian mimicry

Answer 4

Deters predators by mimicking actually dangerous predators (while being harmless)

Question 5

Mullerian mimicry

Answer 5

2+ toxic animals/animals with protective mechanisms develop similar appearances so that if a predator consumes one, they will avoid the other in the future

Question 6

Water cycle elements

Answer 6

• Evaporation: bodies of water -> atmosphere
• Precipitation: atmosphere -> bodies of water (-> runoff)
• Percolation: bodies of water -> ground -> plants
• Transpiration: plant somata -> atmosphere
• Evaporation: bodies of water -> atmosphere

Question 7

Carbon cycle elements

Answer 7

• Atmospheric Co2 -> fixed by photosynthesizers
• Eaten by heterotrophs -> respiration -> back to atmosphere
• Heterotrophs die and decay -> carbonates in soil -> dissolve in water and evaporate back into atmosphere
• Combustion (fossil fuels) -> carbon returns to atmosphere

Question 8

Nitrogen cycle

Answer 8

• Atmospheric nitrogen (N2) -> fixed by nitrifying bacteria into ammonia
• Plants use ammonia to build ATP / amino acids
• Heterotrophs eat plants
• Heterotrophs decay -> denitrifying bacteria convert ammonia in the soil back to atmospheric N2 (gas)

Question 9

Phosphorous cycle

Answer 9

• Phosphorous from rocks/minerals in the crust dissolve in fluids like water
• Plants take up water
• Animals eat plants
• Animals die
• Decompose & phosphate returns to earth