Biology for Kids
Biology is the study of living things. The word says so: bio means life, and logy
means the study of. This course runs from Kindergarten to Grade 12 in twelve steps, each one
building on the one before, with a labelled diagram, a hands-on activity, a note written for the
grown-up, and worksheets that reshuffle so they never run out.
Open the course free →
How the course is built
- It climbs. Unit 1 asks what a living thing even is. Unit 12 is ecosystems and
conservation. Each rung assumes the one below it.
- Answers are included. Every worksheet question has an answer, and the printable
sheet has an optional answer key for the parent.
- Every unit has a note for the grown-up, usually naming the misconception to listen
out for. The commonest ones in biology are surprisingly predictable.
- Accuracy is checked. Every scientific name is verified against the GBIF database,
and where the science is genuinely unsettled, such as how many kingdoms there are, the
lesson says so instead of picking one and calling it fact.
🔎 1 · What Is Biology?
Kindergarten to Grade 1
Biology is the study of living things. The word says so: bio means life, and logy means the study of. A biologist is somebody whose job is to find out how living things work, from the tiniest bacteria to the biggest whale.
What it teaches
- Biology is one of the sciences. It is the one about life.
- Biologists study plants, animals, fungi, and things too small to see without a microscope.
- They study you too. You are a living thing, so you are part of biology.
- Biologists ask questions, look carefully, write down what they see, and try to explain it.
- Looking carefully is the most important skill. Most of biology started with somebody noticing something.
For the grown-up: Start here even with an older child. Knowing that biology is one branch of science, alongside chemistry and physics, gives every later lesson somewhere to sit. If your child asks whether something counts as biology, the useful reply is another question: is it alive, or was it ever?
Try it at home: 🔎 Ten Minutes in the Garden: sit outside, or at a window, and write or draw every living thing you can see in ten minutes. Then count them. Most people are surprised how high the number goes once they include the small things.
Sample worksheet questions and answers
1. What does biology mean?
Answer: The study of living things
2. What does the word part 'bio' mean?
Answer: Life
3. What does the word part 'logy' mean?
Answer: The study of
4. What do we call somebody who studies living things?
Answer: A biologist
5. Is a tree part of biology?
Answer: Yes
6. Is a rock part of biology?
Answer: No
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🌱 2 · Living or Not Living?
Kindergarten to Grade 2
A rabbit is living. A rock is not. That sounds easy, but how do you actually tell? Scientists use a checklist, and anything that does all of the things on it is alive.
What it teaches
- Living things need energy. Animals get it from food and plants make their own from sunlight.
- Living things grow and change. A puppy becomes a dog, an acorn becomes an oak tree.
- Living things react to what is around them. A plant leans towards the light and you jump at a loud noise.
- Living things make more of themselves. Animals have young and plants make seeds.
- Living things get rid of waste, and they are all made of cells.
- One clue is not enough. A river moves and a fire grows, but neither is alive, because they do not do everything on the list.
For the grown-up: The classic trap here is movement. Children decide a car is alive because it moves and a tree is not because it does not. Keep coming back to the whole list rather than a single test, and use the awkward examples on purpose: fire, a river, a seed in a packet, an egg.
Try it at home: 🧺 The Sorting Tray: collect ten things from around the house and garden, including some tricky ones like a seed, a feather and a wooden spoon. Sort them into living, never alive, and once alive. That third pile is the interesting one.
Sample worksheet questions and answers
1. Name one thing all living things need.
Answer: Energy, or food
2. Where do plants get their energy?
Answer: From sunlight
3. What do we call it when a living thing gets bigger?
Answer: Growing
4. Give an example of a living thing reacting to something.
Answer: A plant leaning towards the light
5. How do plants make more of themselves?
Answer: They make seeds
6. Is a rock alive?
Answer: No
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🌻 3 · Plants and How They Grow
Grades 1 to 3
Plants are the only living things that make their own food. Everything else on Earth depends on them for it, which makes them the most important living things there are.
What it teaches
- A plant has roots, a stem, leaves, and usually flowers. Every part has a job.
- Roots hold the plant in the ground and drink up water. The stem carries that water upwards and holds the plant up.
- Leaves make food. They use sunlight, water, and a gas from the air called carbon dioxide.
- That food-making is called photosynthesis. It makes sugar for the plant, and it lets out oxygen, which is the gas you breathe.
- Flowers make seeds. Pollen has to move from one flower to another first, usually carried by insects or by the wind.
- A seed holds a tiny plant and a packed lunch. Give it water and warmth and it starts to grow, which is called germination.
For the grown-up: Two ideas do most of the work here. First, plants make food rather than take it in, which is genuinely strange and worth saying slowly. Second, the oxygen you breathe was let out by a plant. If a child takes only those two away, this unit has done its job.
Try it at home: 🫘 The Bean in a Jar: line a clear jar with damp kitchen paper and tuck a dried bean between the paper and the glass. Keep the paper damp. Over a week the root comes first and grows down, then the shoot grows up. Draw it every day.
Sample worksheet questions and answers
1. Which part of a plant drinks up water?
Answer: The roots
2. Which part of a plant makes food?
Answer: The leaves
3. What is food-making in a plant called?
Answer: Photosynthesis
4. What three things do leaves need to make food?
Answer: Sunlight, water and carbon dioxide
5. Which gas do plants let out?
Answer: Oxygen
6. Which part of a plant makes seeds?
Answer: The flower
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🐾 4 · Animal Groups
Grades 2 to 4
There are millions of kinds of animal, so scientists sort them into groups. The first cut is the simplest one: does it have a backbone, or not?
What it teaches
- An animal with a backbone is a vertebrate. One without is an invertebrate.
- Most animals are invertebrates. Insects, spiders, worms, snails and jellyfish all have no backbone.
- There are five groups of vertebrate: fish, amphibians, reptiles, birds and mammals.
- Mammals have hair or fur, and the mothers feed their young on milk. You are a mammal.
- Birds have feathers, a beak, and lay eggs. All birds have feathers and nothing else does.
- An insect has six legs and a body in three parts. A spider has eight legs and two parts, so a spider is not an insect.
For the grown-up: Sorting is the real skill here, not memorising. Ask which group something belongs to and then, more usefully, how they know. A child who says 'a bat is a mammal because it has fur and feeds milk' has understood something. One who says 'a bat is a bird because it flies' has told you exactly what to work on next.
Try it at home: 🐾 Twenty Questions, Animal Edition: one person thinks of an animal. Everyone else may only ask yes or no questions, starting with 'does it have a backbone?'. Good questions cut the possibilities in half each time.
Sample worksheet questions and answers
1. What do we call an animal with a backbone?
Answer: A vertebrate
2. What do we call an animal without a backbone?
Answer: An invertebrate
3. How many groups of vertebrate are there?
Answer: Five
4. Name the five vertebrate groups.
Answer: Fish, amphibians, reptiles, birds and mammals
5. Which group are you in?
Answer: Mammals
6. What covers a bird and nothing else?
Answer: Feathers
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🦋 5 · Life Cycles
Grades 2 to 4
Every living thing is born, grows, has young of its own, and dies. That circle is a life cycle. Some animals change so completely along the way that the young and the adult look like different creatures altogether.
What it teaches
- A life cycle goes round: born, grow, have young, and the young start it all again.
- A butterfly goes egg, caterpillar, chrysalis, butterfly. The big change inside the chrysalis is called metamorphosis.
- The caterpillar and the butterfly are the same animal. It does not turn into a different one.
- A frog goes egg, tadpole, froglet, frog. The tadpole grows legs and loses its tail.
- Some animals change much less. A baby grasshopper looks like a small adult and just gets bigger.
- Plants have life cycles too: seed, seedling, grown plant, flower, seed again.
For the grown-up: Children often think the caterpillar dies and a butterfly appears. It is the same individual animal the whole way through, rebuilt inside the chrysalis. Saying that plainly clears up a surprising amount. If you can watch tadpoles in spring, do; nothing on a page competes with it.
Try it at home: 🦋 The Four Card Shuffle: draw the four butterfly stages on four cards and the four frog stages on four more. Shuffle both sets together and race to lay them out as two correct circles. There is no first card in a circle, which is the whole point.
Sample worksheet questions and answers
1. What do we call the circle of birth, growth and young?
Answer: A life cycle
2. What are the four stages of a butterfly?
Answer: Egg, caterpillar, chrysalis, butterfly
3. What is the big change inside a chrysalis called?
Answer: Metamorphosis
4. Is the caterpillar the same animal as the butterfly?
Answer: Yes
5. What are the stages of a frog?
Answer: Egg, tadpole, froglet, frog
6. What does a tadpole grow as it changes?
Answer: Legs
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🫀 6 · Your Amazing Body
Grades 3 to 5
Your body is doing an enormous amount right now without being asked. Your heart is beating, your lungs are filling, your stomach is working, and your brain is running all of it while you read this.
What it teaches
- Your body is organised into systems, and each one has a job. Scientists usually count about eleven of them.
- Your skeleton holds you up and protects the soft parts. An adult has 206 bones. A baby is born with about 300, and some of them join together as it grows.
- Your heart pumps blood. It has four chambers, and it beats about 100,000 times a day.
- Your lungs take in oxygen and let out carbon dioxide. That swap is why you breathe.
- Your digestive system breaks food down: mouth, then a tube called the oesophagus, then stomach, then the small and large intestines.
- Your brain is in charge. It sends and receives messages along nerves, and it is protected by your skull.
For the grown-up: The number of bones is a good chance to teach something bigger than a fact. A baby really does have more bones than you, because some fuse as they grow. Facts that change with age are more interesting than facts that do not, and they make it clear that a body is a growing thing rather than a fixed machine.
Try it at home: 🫀 Find Your Pulse: put two fingers on your wrist below the thumb, or on your neck beside the windpipe, and count the beats in fifteen seconds. Multiply by four. Now run on the spot for a minute and do it again. Write down both numbers and talk about why they differ.
Sample worksheet questions and answers
1. How many bones does an adult have?
Answer: 206
2. Does a baby have more or fewer bones than an adult?
Answer: More
3. Why does the number of bones go down?
Answer: Some bones join together as you grow
4. How many chambers does the heart have?
Answer: Four
5. What does the heart do?
Answer: Pumps blood around the body
6. Which gas do your lungs take in?
Answer: Oxygen
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🌾 7 · Habitats and Food Chains
Grades 4 to 6
A habitat is the place an animal or plant lives, and it has everything that living thing needs. Inside a habitat, energy passes from one living thing to the next, and drawing that as a chain shows you who depends on whom.
What it teaches
- A habitat provides food, water, shelter and a place to raise young. A pond, a wood and a desert are all habitats.
- An adaptation is a feature that helps something survive where it lives. A camel's hump and a cactus's spines are both adaptations.
- Every food chain starts with a plant, because plants make their own food. A plant in a chain is called a producer.
- Animals that eat are called consumers. A herbivore eats plants, a carnivore eats animals, and an omnivore eats both.
- The arrow in a food chain means 'is eaten by'. It always points the way the energy travels.
- Decomposers such as fungi and worms break down dead things and return the goodness to the soil, which is where a food chain quietly starts again.
For the grown-up: The arrow direction is the single most common mistake, and it matters, because it is really about energy rather than eating. Grass, arrow, rabbit, arrow, fox. If your child draws the arrows pointing at the mouth of the eater, that is worth correcting every time until it sticks.
Try it at home: 🌾 Build the Chain, Then Break It: write the parts of a local food chain on separate cards and lay them out with arrows. Now remove one card and talk about what happens to everything else. Removing the plant is the most dramatic, and shows why producers matter.
Sample worksheet questions and answers
1. What is a habitat?
Answer: The place where a living thing lives
2. Name four things a habitat provides.
Answer: Food, water, shelter and a place for young
3. What is an adaptation?
Answer: A feature that helps something survive where it lives
4. What does every food chain start with?
Answer: A plant
5. What is a plant called in a food chain?
Answer: A producer
6. What does the arrow in a food chain mean?
Answer: Is eaten by
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🔬 8 · Cells: The Building Blocks
Grades 5 to 8
Every living thing is built from cells. Some living things are a single cell. You are made of trillions of them, and almost all are far too small to see without a microscope.
What it teaches
- Cell theory says three things: all living things are made of cells, the cell is the smallest unit that is alive, and every cell comes from another cell.
- Animal and plant cells share parts. The nucleus is the control centre and holds the DNA. The cytoplasm is the jelly where things happen. The cell membrane is the skin that decides what goes in and out.
- Mitochondria release energy from food. Cells that need a lot of energy, such as muscle cells, have many of them.
- Plant cells have three extra parts: a stiff cell wall for support, chloroplasts that make food from sunlight, and one large vacuole full of water.
- Cells come in shapes that suit their job. A nerve cell is long and thin for carrying messages. A red blood cell is a flat disc so it can slip through narrow vessels.
- Groups of similar cells make a tissue, tissues make an organ, and organs work together as a system.
For the grown-up: Scale is what makes this hard. Cells are not small like a grain of rice is small. A useful comparison: if one of your cells were the size of a full stop on this page, you would be about as tall as a mountain. Getting the scale wrong makes every later idea slippery.
Try it at home: 🔬 Onion Skin: peel the thin, clear layer from between two layers of an onion, lay it flat on a plate with a drop of water, and look at it with any magnifier you have. Even a phone camera zoomed right in shows the brick-like pattern of cell walls.
Sample worksheet questions and answers
1. What is the smallest unit of life?
Answer: The cell
2. Which part of a cell is the control centre?
Answer: The nucleus
3. What is stored in the nucleus?
Answer: DNA
4. What is the jelly inside a cell called?
Answer: Cytoplasm
5. What decides what goes in and out of a cell?
Answer: The cell membrane
6. Which part releases energy from food?
Answer: The mitochondria
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🗂️ 9 · Classifying Life
Grades 6 to 8
There are millions of kinds of living thing, and biologists sort them into a system of nested groups. Each step down the ladder holds fewer kinds, and members that are more alike.
What it teaches
- The ranks run domain, kingdom, phylum, class, order, family, genus, species. Species is the smallest.
- Every species has a two word scientific name: the genus with a capital letter, then the species in lower case, both in italics. Humans are Homo sapiens.
- Scientific names are used worldwide, so a biologist anywhere knows exactly which living thing you mean, whatever language they speak.
- There are three domains: Bacteria, Archaea and Eukarya. Every living thing sits in one of them.
- How many kingdoms there are depends on which system you use. School books often teach five, some teach six, and biologists still argue about it. It is a way of organising, not a law of nature.
- A species is usually defined as a group whose members can breed together and produce young that can themselves have young.
For the grown-up: This unit is a good place to show that science changes its mind. The number of kingdoms genuinely differs between textbooks, and that is not a mistake, it is what an active field looks like. A child who learns that classification is a human tool, rather than a fact handed down, is better prepared for everything that follows.
Try it at home: 🗂️ Classify the Kitchen: pick twenty things from a cupboard and build your own nested system for them, with at least four levels. Then swap with somebody and try to file a new object into their system. Arguing about where it goes is exactly what taxonomists do.
Sample worksheet questions and answers
1. What is the smallest rank in classification?
Answer: Species
2. What is the largest rank?
Answer: Domain
3. Name the ranks in order from domain down.
Answer: Domain, kingdom, phylum, class, order, family, genus, species
4. How many words are in a scientific name?
Answer: Two
5. What is the scientific name for humans?
Answer: Homo sapiens
6. Which part of a scientific name has a capital letter?
Answer: The genus
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🧬 10 · Genes and Inheritance
Grades 7 to 10
You look a little like the people you came from, and that is not a coincidence. Instructions are passed from parents to offspring, written in a molecule called DNA.
What it teaches
- DNA is a long molecule shaped like a twisted ladder, called a double helix. It sits inside the nucleus of a cell.
- The rungs of the ladder are made from four bases: A, T, C and G. A always pairs with T, and C always pairs with G.
- A gene is a section of DNA that carries the instructions for one thing, such as a protein.
- DNA is packed into chromosomes. A human body cell has 46 chromosomes, arranged as 23 pairs.
- You get one chromosome of each pair from each parent, which is why you can resemble both.
- Some versions of a gene are dominant and show up whenever they are present. Others are recessive and only show when both copies are the recessive one. Gregor Mendel worked this out by breeding pea plants in the 1860s.
For the grown-up: Two cautions. First, most traits are not decided by a single gene; eye colour is far more complicated than the simple version taught with Punnett squares, so treat the pea-plant examples as a model rather than the whole truth. Second, inherited does not mean unchangeable: what you eat, do and practise matters too.
Try it at home: 🧬 The Family Trait Survey: pick three traits that are easy to spot, such as whether earlobes hang free or are attached. Survey everybody you can and tally the results. Then look at which traits run in your family and which do not.
Sample worksheet questions and answers
1. What shape is DNA?
Answer: A double helix, like a twisted ladder
2. Where in a cell is DNA found?
Answer: In the nucleus
3. How many bases are there in DNA?
Answer: Four
4. Name the four bases.
Answer: A, T, C and G
5. Which base pairs with A?
Answer: T
6. Which base pairs with C?
Answer: G
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🦕 11 · Evolution and Natural Selection
Grades 8 to 11
Living things change over very long spans of time. Charles Darwin explained how, and the explanation is simpler than most people expect, though it is easy to get subtly wrong.
What it teaches
- Within any species, individuals vary. Some are faster, some better hidden, some able to eat a wider range of food.
- More young are born than can possibly survive, so there is competition.
- Individuals whose variations suit their surroundings tend to survive longer and have more young, and they pass those variations on. That is natural selection.
- Over very many generations the whole population shifts. No individual changes: what changes is which individuals are common.
- Fossils record this. Layers of rock hold the remains of living things from different times, and deeper usually means older.
- Charles Darwin published his explanation in 1859, after years of evidence gathering including his voyage on HMS Beagle.
For the grown-up: The commonest error is thinking an individual animal evolves to suit its surroundings, as though a moth darkens because the trees do. It does not. The population changes because darker moths survived to have more young. Listen for 'it changed itself' or 'it needed to' and gently rephrase; that one correction is most of the unit.
Try it at home: 🦕 The Bean Hunt: scatter dried beans of two colours over a patterned rug or a patch of grass and give somebody ten seconds to pick up as many as they can. Count what is left. Repeat three times, starting each round with the survivors doubled. The colour that blends in wins, without any bean changing at all.
Sample worksheet questions and answers
1. What do we call the differences between individuals of a species?
Answer: Variation
2. What is natural selection?
Answer: Better suited individuals survive and have more young
3. Who explained natural selection?
Answer: Charles Darwin
4. In which year did Darwin publish his explanation?
Answer: 1859
5. What was the name of Darwin's ship?
Answer: HMS Beagle
6. Does an individual animal evolve during its life?
Answer: No
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
🌍 12 · Ecosystems and Keeping Them Healthy
Grades 9 to 12
An ecosystem is everything in a place, living and non-living, and the way it all interacts. The last rung of this ladder is about how those systems hold together, and what happens when they do not.
What it teaches
- An ecosystem includes the living parts, such as plants and animals, and the non-living parts, such as sunlight, water, soil and air.
- Food chains join into food webs, because most living things eat more than one thing and are eaten by more than one thing.
- Biodiversity means the variety of living things in a place. A system with more variety usually recovers better from damage, because more paths through the web remain.
- Matter cycles round. Carbon, water and nitrogen all move between living things, the air, the water and the soil, again and again.
- Energy does not cycle. It arrives from the Sun, passes along the chain, and is lost as heat at every step, which is why chains are short.
- Human choices change ecosystems, through habitat loss, pollution and a changing climate. Conservation is the work of protecting and restoring them, and it succeeds often enough to be worth doing.
For the grown-up: The distinction worth landing here is that matter cycles but energy does not. It explains why food chains are rarely more than four or five links, and it is the idea that turns a list of facts into a system a student can reason about. This is also the natural point to talk about what your own family can actually do, which beats despair.
Try it at home: 🌍 Survey a Square Metre: mark out one square metre of garden, park or verge and record every living thing in it, plus the non-living conditions: sun or shade, damp or dry, bare or covered. Do the same on a different square and compare. Two metres apart can be two different worlds.
Sample worksheet questions and answers
1. What is an ecosystem?
Answer: The living and non-living things in a place and how they interact
2. Name a non-living part of an ecosystem.
Answer: Sunlight, water, soil or air
3. What do you call food chains joined together?
Answer: A food web
4. Why do food chains join into webs?
Answer: Most living things eat more than one thing
5. What does biodiversity mean?
Answer: The variety of living things in a place
6. Why does more biodiversity help?
Answer: The system recovers better from damage
Worksheets are generated fresh every time. Press New Worksheet in the app for a new set, with a printable answer key.
Please note: BrightSprouts Academy is a supplemental learning resource for
families. It is not affiliated with, endorsed by, or a replacement for any official school
curriculum, school district, state education agency, or the U.S. Department of Education. Our
lessons follow widely used US scope-and-sequence guidance as a helpful reference only. Always
follow your child's school, district and state requirements.