Lesson 3.1

Populations
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Slide 1: Diapositive
BiologieMiddelbare schoolvwoLeerjaar 4

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Populations

Slide 1 - Diapositive

What is a population?

Slide 2 - Question ouverte

With reference to the following statements about a woodland ecosystem. Which statement describes a population?
A
All the oak trees
B
All the plants
C
All the plants and animals

Slide 3 - Quiz

Population size
immigration
emigration
death
birth

Slide 4 - Question de remorquage

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

Slide 5 - Diapositive

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

Slide 6 - Diapositive

Carrying capacity
Environmental resistance
Few reproducing individuals
Exponential growth

Slide 7 - Question de remorquage

What is population density?

Slide 8 - Question ouverte

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

Slide 9 - Diapositive

Density independent
Density dependent
Light
parasitism
earthquake
competition
disease

Slide 10 - Question de remorquage

Homework
  • Read pages 440-441
  • Complete this lessonup
  • Complete worksheet human population growth

Slide 11 - Diapositive