Living Processes and Biodiversity

Making sense of the living world

There are millions of kinds of living thing, and biology makes sense of this variety in two connected ways: by GROUPING living things so we can name and study them, and by valuing the VARIETY of life itself. ⭐⭐ CLASSIFICATION is sorting living things into groups by their shared features. The smallest group is a SPECIES, a set of similar organisms that can breed together to produce fertile offspring. Similar species are grouped together, up to the largest groups, so that any organism can be named and placed. ⭐ To identify an unknown organism, scientists use an IDENTIFICATION KEY: a series of yes-or-no questions about features that narrows the choices down until only one organism is left. ⭐⭐ BIODIVERSITY is the variety of different species living in a place. High biodiversity helps an ecosystem stay stable, because many species linked in food chains can cope better with change. Human activity, such as habitat loss and pollution, can reduce biodiversity. This module is classification and biodiversity. The cell-level living processes have their own module. ⚠️ Carry one question the whole way through: how is this living thing grouped, and how does variety help keep an ecosystem healthy?

Grouping, identifying, valuing

The three ideas of this topic. Read across each one.

Tap the two classification statements

Tap the TWO statements that are about CLASSIFYING or identifying living things, rather than about biodiversity.

• A species is a group of organisms that can breed to produce fertile offspring.
• A key uses yes-or-no questions about features to name an organism.
• A rainforest has a huge variety of different species living together.
• Clearing a habitat can reduce the variety of life in an area.

Reading an ecosystem

A pond that once had many kinds of plant, insect, fish and bird is polluted, and now only a few tough species survive. What has happened to the ecosystem, and why does it matter?

• Its biodiversity has fallen, which can make the ecosystem less stable and less able to cope with further change
• Its biodiversity has increased, because the tough species are stronger
• Nothing important has changed, as long as some life remains
• It has been reclassified into a new species

The words this topic uses

Six terms this topic turns on. Learn them and the living world reads clearly.

Pair each term with its meaning

Two true things about the living world

Select the TWO statements that are true.

• High biodiversity tends to make an ecosystem more stable
• Classification groups living things by the features they share
• Human activity has no effect on biodiversity
• A key works by breeding two species together

Answering a living-world question

Strong answers use the precise word and link variety to the health of an ecosystem. ⭐⭐ USE THE RIGHT GROUPING WORD. Keep species (the smallest group, able to breed to fertile offspring) apart from the wider groups, and say classification means sorting by shared features. The exact term earns the mark. ⭐ EXPLAIN WHY BIODIVERSITY MATTERS. Do not just say variety is good; say that many linked species make an ecosystem more stable and better able to cope with change. The because is where the marks are. ⭐⭐ DESCRIBE HUMAN IMPACT FAIRLY. State plainly that habitat loss and pollution can reduce biodiversity, and that protecting habitats helps. Keep it factual and about the science, not about blaming a group of people. DO NOT DRIFT INTO CELL PROCESSES OR EQUATIONS. Photosynthesis, respiration and transport at the cell level have their own module; here, keep the focus on classification and biodiversity, and describe any process in words, not as an equation. ⚠️ A note on accuracy. Do not invent figures for how many species live somewhere or how fast biodiversity is changing; describe the direction and the reasons. Keep the one question to hand: how is this living thing grouped, and how does variety help keep an ecosystem healthy?

Order how to use a key

Put the steps of using an identification key to name an unknown small animal into a sensible order.

• Look closely at the features of the unknown animal
• Answer the first yes-or-no question in the key
• Follow the answer to the next question
• Keep answering, narrowing the choices each time
• Arrive at the single name the key leads you to

Build a biodiversity point

Assemble one sentence that explains why biodiversity matters.

The living-world run

Five quick decisions about classification and biodiversity. Three lives.

A well-stocked library

Leave biology aside for a moment. Think about how a large public library both organises its books and benefits from having so many different ones. ⭐ First, the organising. The books are sorted into sections by what they have in common: cookery together, history together, poetry together. Because everything is grouped by shared features, a librarian can find any single book quickly, and a reader can be pointed to exactly the right shelf. The whole point of the grouping is to name and locate things in a huge collection. ⭐⭐ Second, the variety. A library that stocks a wide range, many subjects, many voices, serves far more readers than one with only a few kinds of book, and it copes better when tastes change: if one subject falls out of fashion, plenty of others carry the library on. A narrow collection is fragile; a varied one is resilient. So two ideas sit side by side: sort things into groups by shared features so you can find them, and value a wide variety because it keeps the whole collection strong. ⚠️ Hold that picture. The living world is understood the same way: living things are sorted into groups by shared features, and a wide variety of them keeps an ecosystem strong.

Finish each living-world line

A group of similar organisms that can breed together to produce fertile offspring is a _____. Sorting living things into groups by their shared features is called _____. The variety of different species living in a place is called _____. The place where an organism lives is its _____. A series of yes-or-no questions used to name an organism is an identification _____.

Three living-world puzzles

Three situations are described. For each, choose the best scientific reading.

• A student finds an unfamiliar insect and wants to name it without asking anyone.
• A wildflower meadow with dozens of plant and insect species is replaced by a single crop grown across the whole field.
• A learner says a horse and a donkey are the same species because they can have a foal together.

Explain classification and biodiversity

Explain how biology organises the living world: what a species is, what classification means and how a key is used, what biodiversity is and why high biodiversity matters, and how human activity can affect it. Describe processes in words, not equations, and invent no figures.

• Explain what a species is, including fertile offspring
• Explain what classification means and how a key is used
• Explain what biodiversity is
• Explain why high biodiversity helps an ecosystem stay stable
• Explain one way human activity can reduce biodiversity