Review: adaptation, genes and soil
Living things are adapted to their climate. Structural adaptations are body features and behavioural adaptations are actions, such as migration. The living parts of an ecosystem are biotic and the nonliving parts, such as water, light and temperature, are abiotic. Genes pass traits like eye colour and leaf shape from parents to offspring, while the environment can also change growth, as with a seedling grown in the dark. Soil is a mixture of rock pieces, humus, air and water. Weathering and erosion start it forming and decomposers return nutrients to it. Sand has the biggest particles and drains fastest, clay the smallest and drains slowest. Soil lies in layers: topsoil, subsoil and bedrock. Erosion and overgrazing can lead to desertification, which plants and trenches help slow.
| Topic | Key idea |
|---|---|
| adaptation | structural (body) or behavioural (action) |
| genes | pass traits to offspring |
| light | strength and length affect growth |
| soil | rock pieces, humus, air and water |
| erosion | slowed by roots, trees and trenches |
| Feature | Kind |
|---|---|
| large ears | structural |
| sleeping in a burrow by day | behavioural |
Memory map. With a grown-up, draw a mind map with “Life and soil” in the middle and branches for adaptation, genes, light, soil layers, soil types and erosion. Add one example to each branch. Look for one thing you would like to find out more about.