EES_YR3_LSN3A

• Biologie
• Middelbare school
• vwo
• Leerjaar 3

EES_Y3_LSN3A

Evolution, Ecology & Sustainability

Population size

immigration

emigration

death

birth

Population growth

Involves:

1. Biotic potential: max reproduction rate given all the resources the population needs
2. Environmental resistance: all factors that may limit growth. (scarcity of resources, predation, climate conditions etc)
3. Carrying capacity: max population size that can be supported by a particular environment

Population curves

• J-curve: often seen in fast reproducing organisms that colonise a new environment. Exponential growth followed by hitting a limiting factor and often the population crashes
• S-curve: Exponential growth until population hits environmental resistance and stabilises around the carrying capacity

Carrying capacity

Environmental resistance

Few reproducing individuals

Exponential growth

What is population density?

Environmental resistance

Can be:

• Density indepent: these factors influence all organism in a population irrespective of population density. Can be biotic of abiotic
• Density dependent: the influence of these factors on population size depend on the density of the population. Usually the higher the density the bigger the impact of these factors. Always biotic

What is a square called that we use to sample populations?

1. grid
2. quadrat
3. cube
4. quarter

These four 1m2 squared quadrats were place in a 8m2 garden. Estimate the total population of flowers in the whole garden.

1. 16
2. 8
3. 40
4. 20

Which one of these is a correct assumption you need to make about a population between samplings?

1. It is a closed population
2. It won't rain between samplings
3. There are lots of deaths
4. There are lots of births

If 50 crabs were captured and marked and then released and then a few days later 25 were caught and of those 5 were marked. What would the estimate of the population be?

1. 500
2. 250
3. 75
4. 200

An area of 5m2 was sampled using a quadrat to find a total of 10 sunflowers. If the area of the field was 200m2 , what is the estimated number of sunflowers in the field?

1. 20
2. 40
3. 400
4. 2000

A factor that would increase the size of the population

1. Emmigration
2. Death Rate higher than Birth Rate
3. Birth Rate Higher than Death Rate
4. Drought

A factor that is more likely to affect crowded population much more than spread out population

1. Density dependent factor
2. Limiting factor
3. Natural disaster
4. Density independent factor

A factor that decreases the population or keeps it from increasing

1. Limiting factor
2. Food surplus
3. High birth rate
4. Carrying capacity

Example of a density independent factor

1. Natural Disaster
2. Disease
3. Resource Availability/Competition
4. Predators

What is the carrying capacity of the following graph?

1. Around 500
2. More than 500
3. Less than 500
4. Around 600

What is incorrect in the tolerance curve below?