Physical Abiotic Factors in Ecosystems Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Explore how physical environmental factors including light intensity, temperature, moisture levels, wind intensity and direction affect communities of o...

• Explain how light intensity affects the distribution and behaviour of organisms in ecosystems
• Describe the impact of temperature on community structure and organism survival
• Analyse how moisture levels influence where different species can live and thrive
• Evaluate the effects of wind intensity and direction on ecosystem dynamics

Key ideas to keep in view

Use this lesson to stay inside B4.1 Ecosystems while connecting the detail back to the wider B4: Community level systems topic.

• B4: Community level systems
• B4.1 Ecosystems
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from Physical Abiotic Factors in Ecosystems before testing yourself from memory.

• Walk into a forest and you'll notice something obvious: different plants grow in different places. Ferns thrive in the shady undergrowth while oak trees dominate the sunny canopy. This isn't random — it's controlled by physical factors in the environment.
• These non-living factors are called abiotic factors. They act like invisible filters, determining which organisms can survive where. Get the conditions wrong, and species can't establish themselves.
• Non-living environmental conditions that affect the distribution and abundance of organisms in an ecosystem. Include physical factors like temperature, light, moisture, and wind.
• Trap: Many students think abiotic means 'dead things like fallen logs'. Actually, abiotic factors are environmental conditions — they were never alive in the first place. A rotting log is biotic because it was once living.
• Light intensity determines how much energy is available for photosynthesis. Think of it as the power supply for the entire ecosystem — without enough light, plants can't make glucose, and the whole food web collapses.
• Different plants have evolved different light requirements. Shade-tolerant species like moss can photosynthesise in low light conditions, while sun-loving plants like sunflowers need intense, direct sunlight to thrive.
• The amount of light energy reaching a particular area per unit time, measured in lux. Directly affects the rate of photosynthesis in plants.
• This creates distinct zones in ecosystems. Forest floors receive only 2-5% of the light that hits the canopy. That's why you find completely different plant communities at different heights — each adapted to their light environment.
• Temperature controls the speed of life itself. Every chemical reaction in living organisms — from photosynthesis to respiration — depends on temperature. Too cold, and reactions slow to a crawl. Too hot, and enzymes denature.
• Most organisms have an optimal temperature range where they function best. Outside this range, they struggle to survive. This is why you find polar bears in the Arctic and camels in deserts — each is adapted to their temperature environment.

Continue through the topic

Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.