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How Extinction Happens And Why It Matters – KS3 Biology Lesson Plan

Here today, gone tomorrow – Dr Joanna Rhodes shares a selection of engaging activities to help learners understand the causes of extinction past and present

  • How Extinction Happens And Why It Matters – KS3 Biology Lesson Plan

The recognition that extinction is something that is happening now, along with reinforcement of the need to reduce habitat loss, limit global warming and end the poaching of endangered species, is an important part of KS3 science.

Based on current rates, the earth could be moving towards a mass extinction with species disappearing every day at a rate not measured in the geological record since the end of the dinosaurs.

Not only do we have a moral and cultural responsibility to conserve endangered species, but biodiversity also has an impact on the human population by maintaining the future possibility that plant species might be identified for medicines, keeping damage to food chains and food webs to a minimum and protecting our future food supply.

There are strong cross-curricular links to geography and opportunities to link biodiversity to your SMSC program.

In this lesson, students will learn about biodiversity and how animals are adapted to live in their surroundings. This will support an understanding of the reasons for species becoming extinct and what could be done to reduce the rate of extinctions currently taking place.

Students will also investigate whether science can bring species back from extinction and they will debate the ethical and moral dilemmas surrounding this, using Jurassic Park for inspiration!

Starter Activity

Create a game of habitat snap by laminating playing card images of different habitats (eg the desert, the arctic, plains, forest, rainforest, mountain, ocean, river, pond, fields and city). Now laminate pictures of different animals and plants that could be found in these habitats.

As students play the game they should call snap when the animal matches its habitat. To receive the points they must state why the animal is adapted to survive in that habitat.

As an extension you could ask the students themselves to make the cards to play with each other. After the game, display on the board an animal or plant with a habitat that does not match.

Ask students to explain why the animal or plant would not survive in this habitat, for example a cactus in a rainforest or a snake in the arctic. The aim is to prompt students to think about what habitat loss might mean for a species’ survival.

Main Activities

1. Mrs Gren
The Mrs Gren acronym helps students to remember the necessary features of living organisms: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition. If any of these functions are hampered by a change to the environment then the species will go into decline.

Divide students into teams and ask them to work on case studies for critically endangered species, for example, the orangutan. To create more case studies use the WWF species directory containing critically endangered species with explanations of how why they are endangered.

Orangutan case study
A family group of orangutans live in the rainforest in Borneo. Recently a logging company has cleared an area close to their territory and has planted oil palm trees to produce biofuel.

The orangutans have to cross this area to reach their usual feeding ground and due to the damage they are causing many of them are being shot. Some of the female orangutans have been killed so their infants can be sent away to Taiwan where it is popular to have an orangutan for a pet.

There are very few females left in the group. The river separating the group from a large area of rainforest is too wide to cross and the logging company is closing in on the small territory they have left.

Ask students to consider which of the Mrs Gren processes are affected in each scenario you share with them, and how humans may have contributed to how these animals have become endangered.

For the orangutan, typical responses might include that the logging of rainforest trees restricts movement, growth is prevented as the young are poached to become pets, which also has an effect on reproduction. Nutrition suffers as the habitat is lost and forest removed.

2. A new epoch
Humanity’s impact on the Earth is now so profound that a new geological epoch – the Anthropocene – needs to be declared, according to an official expert group who presented the recommendation to the International Geological Congress in August 2016.

Ask students to be text detectives and to identify the main potential indicators that we are in a new geological epoch using the Guardian article describing the response from the International Geological Congress. Students will discover that the evidence that has been presented that humans have irreversibly changed the geology of the Earth, which includes:

i) Extinction rates of animals and plants pushed far above the long-term average with 75% of species to become extinct in the next 200-500 years

ii) Increased levels of climate-warming CO2 in the atmosphere at the fastest rate for 66m years;

iii) High levels of plastic in our waterways and oceans, with microplastic particles now virtually everywhere, and plastics will likely leave identifiable fossil records for future generations to discover;

iv) Double the nitrogen and phosphorous in our soils in the past century with fertiliser use. This is likely to be the largest impact on the nitrogen cycle in 2.5bn years;

v) A permanent layer of airborne particulates in sediment and glacial ice such as black carbon from fossil fuel burning;

vi) The rise of the domestic chicken leaving fossilised remains throughout the Earth making it one of the most common fossils on the planet.

Summary

If we are indeed in a new geological epoch then it is possible that with future scientific advancements in cloning we could create a Holocene Park for visitors to come and view extinct species from the epoch we are emerging from, including the dodo, Barbary lion, great auk, quagga and even a woolly mammoth, a creature that only just made it into the Holocene epoch before becoming extinct.

Assuming that technology to clone these animals from preserved DNA is possible what would such a park look like? In this activity students complete a web quest to find and research the animals and plants that have become extinct in the Holocene epoch and design a park with the habitats to suit the needs of those animals.

HOME LEARNING

Genetic recovery of extinct species
Ask students to consider the ethical arguments for and against de-extinction. Each of the Jurassic Park films has been a cautionary tale against this technology, but on the other hand it is hard to imagine the dodo posing any sort of threat to zookeepers or the public.

One of the main arguments against de-extinction is the massive financial investment it would require, along with the low chances of success, meaning that it would be better to invest the money into greater attempts to conserve critically endangered species before they become extinct.

Encourage students to form opinions and present their own arguments and those found in their research in a debate, as a newspaper article or presentation. They could use Pleistocene Park in Russia as an example of the recreation of an ecosystem. In an innovative approach to debating, ask students to produce a sequence of hypothetical ‘tweets” with one group arguing in favour and the other group arguing against.

STRETCH THEM FURTHER

Using a highly developed activity from the Crossing Boundaries secondary school biodiversity project students learn the meaning of biodiversity, species richness, endemism, and abundance by analysis of bird populations on a fictional island.

The resource includes an interactive PDF map to explore various ways to represent and compare biodiversity across eco-regions. Rather like a genuine experiment in the field, the activity encourages students to engage with the vocabulary of biodiversity and also gain skills in evaluating and communicating their own findings on bird biodiversity.

Dr. Joanna Rhodes is associate assistant principal at Shelley College, Oxford

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