Ecosystems, interdependence and human impact
Ecology studies how organisms depend on each other and their environment, and what happens when humans change the balance.
Lesson overview
What you'll learn in this lesson
Explain inheritance, variation, evolution and ecological relationships at GCSE standard.
Key learning points
- • Interdependence and adaptation
- • Sampling and quadrats
- • Cycles and human impact
This lesson at a glance
- 30 minutes
- 15 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 15
Watch first
Ecosystems, interdependence and human impact
An English teaching video on this topic from LearnScienceWithB. Watch it, then scroll down for the lesson.
In a nutshell
Explain inheritance, variation, evolution and ecological relationships at GCSE standard.
Learning cycle
Part 2 of 15
Learning cycle 1 of 2
Part 1 · Interdependence and adaptation
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 15
Learn
Interdependence and adaptation
Organisms compete for resources: animals for food, mates and territory; plants for light, water, space and mineral ions. Adaptations may be structural, behavioural or functional, and extremophiles survive conditions such as high temperature or salinity that would kill most organisms.
Explore the idea
Part 4 of 15
Learn
Sampling and quadrats
A quadrat placed using random coordinates estimates population size in a uniform area, and mean per quadrat multiplied by total area estimates the population. A transect measures how distribution changes along an environmental gradient, such as from a path into woodland. More samples improve reliability.
Quick check
Part 5 of 15
Quick check
Quadrats must be placed randomly to
Quick check
Part 6 of 15
Quick check
A transect is used to measure
Reset break
Part 7 of 15
Pause
That's sitting 1 of 2 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 8 of 15
Learning cycle 2 of 2
Part 2 · Cycles and human impact
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 9 of 15
Learn
Cycles and human impact
Carbon and water cycle continuously, with decomposers returning nutrients to the soil. Human activity reduces biodiversity through deforestation, peat destruction, pollution and land use for building and farming. Greenhouse gas emissions drive global warming, and conservation programmes, breeding schemes and habitat protection aim to reverse the losses.
Quick check
Part 10 of 15
Quick check
Decomposers are important because they
Quick check
Part 11 of 15
Quick check
Deforestation reduces biodiversity mainly by
Explore the idea
Part 12 of 15
Worked example
Worked answer: describe how to estimate the number of daisies in a field using quadrats (4 marks)
Use random number pairs as coordinates to place a 1 m² quadrat, avoiding bias in where it lands (1). Count the daisies inside each quadrat and repeat for at least ten quadrats (1). Calculate the mean number per quadrat (1). Multiply the mean by the total area of the field in square metres to estimate the population; more quadrats make the estimate more reliable (1).
Challenge round
Part 13 of 15
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Mastery quiz
Part 14 of 15
Marked quiz
End of lesson quiz: Ecosystems, interdependence and human impact
4 questions, marked with the reasoning shown. No timer.
1. Quadrats must be placed randomly to
2. A transect is used to measure
3. Decomposers are important because they
4. Deforestation reduces biodiversity mainly by
Lesson round-up
Part 15 of 15
Lesson round-up
Ready when you are
Quiz score
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Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?
Ask LunaDo the work
Your written work for this lesson
This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.
Why the school greenhouse failed
A science club grew tomato plants in the school greenhouse. In June the plants grew well: leaves were dark green and the fruit set quickly. In July the club went away for two weeks and left the greenhouse door shut. When they came back, the leaves were curled and pale and most of the fruit had dropped.
The club had a data logger inside. It showed the temperature reached 46 °C on several afternoons and the soil moisture fell close to zero. The club knew photosynthesis needs light, water and carbon dioxide, and that enzymes in a plant work best in a narrow range of temperature. Above that range the enzymes stop working properly.
The club repeated the summer with the door propped open and a water bottle drip on each pot. Temperature peaked at 31 °C and the plants survived.
Written for Good Learning Co.
Reading questions
- Name the variable the club changed the second time, and one variable they kept the same.
- Explain, using the words photosynthesis and enzymes, why the plants were damaged in July.
- Write a conclusion for the club's report, saying how far the evidence supports it.
Method and results
WritingWrite the aim, what you changed, what you measured and what you kept the same, then record your results in a table.
1 page + results table
Conclusion
WritingExplain what your results show and why, using the scientific words from the lesson. Say how you know you can trust them.
6–8 sentences
Labelled diagram
DiagramDraw the apparatus or the process in pencil, label it fully, and photograph it.
1 labelled diagram
Reading and notes
ReadingRead the lesson text again and write the key ideas in your own words.
Half a page of notes
Saved as you type.
Part 1 of 15 · Watch & discover