Natural selection and evolution
At Key Stage Two, students will now be learning about "how animals and plants are adapted to suit their environment in different ways and that adaptation may lead to evolution." However, it is worth assessing students' prior knowledge and misconceptions here as adaptation arises via natural selection, which is not taught until Key Stage Three. For example, a common misconception is that organisms can adapt to new conditions in their lifetimes and pass these adaptations on to their offspring. Although students will have looked at fossils as evidence of evolution at Key Stage Two, they will not have looked at the mechanism for evolution.
Natural selection has moved from Key Stage Four to Key Stage Three and so it may be necessary to take the time to adapt resources previously aimed at Key Stage Four students so that they are more age appropriate. At Key Stage Three, students should learn that "the variation between species and between individuals of the same species means some organisms compete more successfully, which can drive natural selection."
The list provides a range of activities, lesson ideas, film clips, background information, practical tips and suggested teaching strategies.
Visit the secondary science webpage to access all lists: www.nationalstemcentre.org.uk/secondaryscience
Links and Resources
You could show this film directly to your class, or you could watch it through and see which of Ceri's teaching strategies and ideas you can adapt and incorporate into your own teaching of this topic.
Ceri demonstrates a variety of hands-on activities which enable students to visualise the mechanism of natural selection and how it leads to evolution. He looks at mutation, variation, environmental change, competition and adaptation.
This resource has a detailed PowerPoint presentation with accompanying notes and activities which look at the challenges of surviving in an arid environment and how adaptations (such as reduction of water loss through transpiration, surface area and temperature regulation) can help organisms to compete.
This can be linked to how environmental change can lead some organisms becoming less well adapted and less able to survive, leading to extinction.
Here is an example of a hands-on activity that is similar to the one used by Ceri in the resource above to illustrate how variation can affect survival.
This is a good resource for aspects of working scientifically, and the PowerPoint presentations are particulary useful for illustrating predator-prey relationships and how scientists investigated natural selection in the peppered moth.
In order to avoid predators, the caterpillars of some species of moths rest during the day by masquerading as twigs, well-camouflaged and keeping their bodies rigid and still. The aim of this investigation is to determine if caterpillars of the peppered moth show a preferred angle of rest.
It can either be carried out as a field trip, or students can look at images of larvae and measure the angle of rest of each one. Students use calculations and graphs, and perhaps a statistical test, to determine whether larvae do show a preferred angle of rest.
Charles Darwin developed his theory of evolution by natural selection using four important observations:
1. All organisms produce more offspring than survive to adulthood
2. Populations remain more or less constant in numbers
3. Members of the same species show variation in characteristics
4. Some characteristics are inherited and so are passed on to the next generation
This customisable PowerPoint presentation illustrates these observations and starts to explore natural selection.
The presentation in this resource defines the concept of sexual selection and how it relates to natural selection and evolution.
In the Dating Game, students use cue cards to work through two case studies; the first looks at mate choice in the greater bird of paradise and the second looks at competition for mates using reindeer as an example.
These unusual investigations can be combined with background research to create a great project which links together an extensive part of the biology curriculum, including food webs, insect pollination, food security, variation, natural selection, evolution and biodiversity.
Through careful observation and data analysis, students explore which flowers attract different species of bees.
How might bees drive the evolution of flowering plants? Challenge more able students to apply their knowledge and understanding of light, vision, adpatation and natural selection to explain why the bees selected a particular flower.
This is an extensive resource which allows students to explore the evolutionary links between living organisms by selecting species, finding out information about them and seeing their evolutionary relationships.
You can download the interactive Tree of Life and install it on your network for use in class. The activities are designed give students a focus as they search through the interactive animation, but teachers will want to take some time to work through this themselves first to become familiar with it.
The film clip is narrated by Sir David Attenborough and was part of the BBC's Darwin season. It charts the process of evolution, from simple organic molecules in the primordial soup to the variety of species that is seen today.