Chapter 4- Ecologies And Ecosystems- Populations Flashcards Preview

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Flashcards in Chapter 4- Ecologies And Ecosystems- Populations Deck (15):
1

How does Natality affect population size?

Increases population size through reproduction

2

How does immigration affect population size?

Increases population size from external population

3

How does molarity affect population size?

Decreases population size as a result of death

4

How does emigration affect population size?

Decreases population size as a result of loss of external population

5

draw and label a graph showing the sigmoid population growth

Do it

6

Sigmoid population growth curve- why initially is population growth slow?

Shortage or reproducing individuals

7

Sigmoid population growth curve- as numbers increase what is the exponential growth phase?

Rapid increases in population size/growth as natality rate exceeds the morality rate

8

Sigmoid population growth curve- exponential growth phase- why does rapid growth why does it happen?

Because there is an abundance of resources (eg good shelter and water) and limited to environmental problems (disease and predation uncommon)

9

Sigmoid population growth curve- what is transitional phase?

Population continues to grow, eventually competition increases as availability of sources reduce

10

Sigmoid population growth curve- transitional phase- competition increases, why?

Natality starts to fail and morality starts to rise, leading to q slower rate of population growth

11

Sigmoid population growth curve- what is the plateau phase?

Eventually the increasing morality rates equals the Natality and population size becomes constant

12

Sigmoid population growth curve- plateau phase- why does population size become constant?

Population has reached the carrying capacity (K) of the environment
Limited resources, predation and disease all contribute to keeping population size balanced

13

Every species has environment limits- what are the factors affected by pop density?

Predation and parasite
Availability of shelter/water
Nutrient supply
Disease
Accumulation of water

14

Every species has environment limits- what are factors unrelated to population density?

Climate and weather conditions
Availability of light, O2, CO2
Natural disasters

15

What is the formula for a population size over a given period ?

Population size = (Natality + immigration) - ( morality + emigration)

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