Unit 3.5 - Population Growth and Resource Availability

Question 1

What is Size (N)?

Answer 1

• total # of individuals in a given area at a given time
• Larger = safer from pop. decline

Question 2

What is density?

Answer 2

• # of individuals/area
• Ex: (12 panthers/km2)
• High density = higher competition, possibility for disease outbreak, possibility of depleting food source

Question 3

What is distribution?

Answer 3

how individuals in pop. are spaced out compared to each other

Question 4

What are the 3 types of distribution?

Answer 4

1. Uniform (territorial animals)
2. Random (trees)
3. Clumped (herd/group animals)

Question 5

What is sex ratio?

Answer 5

• ratio of males to females. Closer to 50:50, the more ideal for breeding (usually)
  -Die-off or bottleneck effect can lead to skewed sex ratio (not enough females) limiting pop. growth

Question 6

What are density dependent factors for growth factors?

Answer 6

• factors that influence pop. growth based on size:
• Ex: food, competition for habitat, water, light, even disease
• All of these things limit pop. growth based on their size; aka - small pop. don’t experience these, large do

Question 7

What are Density independent factors for growth factors?

Answer 7

• factors that influence pop. growth independent of their size
• Ex: natural disasters (flood, hurricane, tornado, fire)
• It doesn’t matter how big or small a pop. is, natural disasters limit them both

Question 8

Example of density dependent factors

Answer 8

• Food is a density dependent factor. (also a limiting resource)
• When twice as much food was added to the dish, both species increased carrying capacity by about 2x

Question 9

What is biotic potential?

Answer 9

• max. potential growth rate, with no limiting resources
• May occur initially, but limiting resources (competition, food, disease, predators) slow growth, & eventually limit pop. to carrying capacity (k)

Question 10

What type of growth is biotic growth?

Answer 10

exponential growth

Question 11

What is logistical growth?

Answer 11

initial rapid growth, then limiting factors limit pop. to K

Question 12

How to calculate population size

Answer 12

Population Size = (Immigrations + births) - (immigrations + deaths)