POPULATIONS LESSON 1

Specification point 3.4.1: - A population is all the organisms of one species in a habitat.

- Populations of different species form a community.- Within a habitat a species occupies a niche governed by adaptation to both biotic and abiotic conditions. - Population size may vary as a result of

• the effect of abiotic factors• interactions between organisms: interspecific

and intraspecific competition and predation.

Lets get started: Ecosystems

Look at the key terms. Match up the words to the definitions.

Outcomes: Define the terms

population, habitat, community, niche.

Give examples of different abiotic and biotic conditions.

Explain the link between the terms adaptation, abiotic conditions, biotic conditions and niche.

Suggest ways in which ecosystems are affected by both abiotic and biotic conditions and identify these on population growth curves.

Abiotic and Biotic Conditions

Sort these environmental conditions into biotic and abiotic conditions:

Air and water temperatureCompetitionPredation rainfall soil fertilitydisease light intensity shelter

water availability food availabilityHumidity pH

Outcomes: Define the terms

population, habitat, community, niche.

Give examples of different abiotic and biotic conditions.

Explain the link between the terms adaptation, abiotic conditions, biotic conditions and niche.

Suggest ways in which ecosystems are affected by both abiotic and biotic conditions and identify these on population growth curves.

Niches, Adaptation, Biotic factors and Abiotic factors

How do these words link? 1. no two species have the same niche2. Some species appear similar but have different

niches3. Adaptations help organisms avoid competition

and aid them in harsh physical conditions4. Competition is an example of a biotic factor5. Physical conditions are abiotic factors.

https://www.youtube.com/watch?v=xIVixvcR4Jc

Write a paragraph explaining how the relationship between the terms niche, adaptation, biotic and abiotic factors.

Outcomes: Define the terms

population, habitat, community, niche.

Give examples of different abiotic and biotic conditions.

Explain the link between the terms adaptation, abiotic conditions, biotic conditions and niche.

Suggest ways in which ecosystems are affected by both abiotic and biotic conditions and identify these on population growth curves.

Population Growth Curves

Most populations will follow this growth curve pattern.

TASK: Can you identify and explain the different stages here in this growth curve

Outcomes: Define the terms

population, habitat, community, niche.

Give examples of different abiotic and biotic conditions.

Explain the link between the terms adaptation, abiotic conditions, biotic conditions and niche.

Suggest ways in which ecosystems are affected by both abiotic and biotic conditions and identify these on population growth curves.

Population Growth Curves

1. Population numbers are low. It takes time for small numbers to reproduce and increase population. Resources needed are plenty, no competition.

2. Period of rapid growth in population. Resources still plenty and population size doubles with each interval.

3. Rate of growth slows down and population becomes stable. Limiting factors have limited any net growth in population. Resources used up and competition increases. Abiotic conditions may have changed.

4. What eventually could happen?

Outcomes: Define the terms

population, habitat, community, niche.

Give examples of different abiotic and biotic conditions.

Explain the link between the terms adaptation, abiotic conditions, biotic conditions and niche.

Suggest ways in which ecosystems are affected by both abiotic and biotic conditions and identify these on population growth curves.

HW: Due next week

Research and report in detail on how each of these biotic and abiotic factors influence population sizes.1. Temperature2. Competition 3. Light4. Predation5. pH6. Water availabilityI have seen far too often internet copied work. I have software that detects Plagiarism. Don’t do it!

Outcomes: Define the terms

population, habitat, community, niche.

Give examples of different abiotic and biotic conditions.

Explain the link between the terms adaptation, abiotic conditions, biotic conditions and niche.

Suggest ways in which ecosystems are affected by both abiotic and biotic conditions and identify these on population growth curves.