Scientists have discovered over a million different species of living things on Earth, but they estimate there could be as many as nine million in total. That means there are millions of species still to be discovered. All over the world, even in the most difficult and extreme environments, we find life. The life on Earth is hugely varied, from the mold growing on your food, to human beings, to mushrooms in the woods. Scientists have devised a way of classifying these organisms, not only to organize them, but also to highlight similarities and differences.
By the end of this lesson your students will create amazing storyboards like the ones below!
All living things on Earth are linked with each other. Scientists believe all life as we know it has evolved from a common ancestor. This ancestor, often known by the term LUCA (last universal common ancestor), was believed to be alive around 3.5 billion years ago. Since this point, life has become varied through evolution to the wide and beautiful array of life we see all over the the planet.
Nobody knows exactly how many different species exist on Earth. We have discovered just around 1.3 million species, but scientists predict that there are several million more out there that we haven’t discovered yet. New species are constantly being discovered and added to the list. It has been a huge challenge for scientists to catalogue and organized these different types of organisms. The classifying of organisms is known as taxonomy. The system most commonly used is based on the characteristics of living things and this taxonomy was first formalized by Carl von Linné (Carolus Linnæus) in the eighteenth century. The system involves putting living things into groups and multiple subgroups.
The largest groups of life are domains, of which there are three: Bacteria, Archaea, and Eurkarya. Bacteria are all around us, but are difficult to see without a microscope. Archaea are unicellular organisms that are the only life that can survive in the most extreme conditions. All the organisms in the Eukarya Domain have a cellular nucleus in common, and are what we typically think of as "life".
The three domains can then be broken down into kingdoms. There are six kingdoms which all have distinct characteristics. The six kingdoms are Animals, Plants, Fungi, Protists, Bacteria and Archaea. Bacteria and Archaea are considered both domains and kingdoms. The Eurkarya Domain contains the other kingdoms: Animals, Plants, Fungi, and Protista.
Kingdoms in Taxonomic Rank of Life
Multicellular and complex organisms
Heterotrophic - they cannot make their own food
Exist all over the Earth: on land, in the water, or in the air
Autotrophic through photosynthesis
Nearly all contain chlorophyll
Multicellular and complex organisms
mostly unicellular, some protists are multicellular
eukaryotic - meaning they have a cellular nucleus
can be autotrophic or heterotrophic
mostly found in water
most are multicellular and complex
heterotrophic (some are saprotrophic - they feed off dead or decaying organic matter)
Bacteria (a.k.a Eubacteria)
can be autotrophic or heterotrophic
prokaryotic - meaning they lack a membrane-bound nucleus
can survive in extreme conditions
These kingdoms are then split up into groups known as phyla (singular: phylum). Phyla are then divided further into classes. Classes are then broken down into smaller groups known as orders. Orders are broken down into families. Within families there are subgroups known as genera (singular: genus). Finally, the genera are split into categories known as species. The definition of species is a group of organisms that can reproduce and make fertile offspring. In order to remember the order of the naming convention, can use the following mnemonic device: Keep Ponds Clean Or Fish Get Sick. Which refers to Kingdom, Phylum, Class, Order, Family, Genus and Species.
Let's look at an example of how a living thing is classified.
Classification of Humans
This long list of names is normally shortened down to the last two names, Homo sapien, which are the genus and species, known as binomial nomenclature. A lot of the names are written in Latin as historically the first names were written in Latin by Carl von Linné. This agreed naming system allows scientists all around the world to communicate with each other. The kingdom Animalia contains all animals. Animals in the phylum Chordata all have one thing in common: a support rod up their back and in the case of humans, that means our spine. Animals in the mammalia class of which we are a part, all breath air, are warm blooded, and give birth to live young. Other animals in the class include dolphins, dogs, and bats. The order Primates contains animals such as monkeys and gorillas. Primates are categorized as having larger brains for their size than other mammals. The genus Homo contains human beings, but also a number of extinct species closely related to humans.
Essential Questions for Classification
How are organisms named?
How are living things classified?
What defines a species?
Classification Lesson Plans, Student Activities and Graphic Organizers
There are six kingdoms which all have different properties and vary widely. These are Animals, Plants, Fungi, Protists, Bacteria, and Archaea.
Tenodera sinensis (Chinese Mantis) praying mantis native to Asia
Dionaea muscipula (Venus Flytrap) one of a few organisms in the plant kingdom capable of rapid movement
Saccharomyces cerevisiae (Yeast) a fungus used in bread and beer
Euglena a single-celled protist found in lakes and rivers
E. Coli a bacterium that can cause food poisoning
Haloarchaea organisms that live in lakes of high salinity and make the lake turn red
Scientists have changed the number of kingdoms that exist over time as we find out more about the relationships between living things and how they’ve evolved. Archaea were first classified as a different group from protists in 1977. Animals and plants have been their own groups since people started classifying living things.
To make this activity more accessible to struggling or younger students, give the students the names of different living things and have them sort the organisms into the six kingdoms. Alternatively, require only animals, plants, and fungi.
Have your students put key vocabulary into practice. One of the things students can find really difficult is using scientific vocabulary correctly and in the appropriate context. Using a visual representation or visual examples as well as a written one can really help students understand abstract concepts.
Example Classification Vocabulary
A system of naming living things using two names that comes from the genus and the species
An organism that consists of many cells, e.g. oyster mushrooms
An organism that consists of a single cell, e.g. E. Coli
An organism that can make its own food, e.g. green plants
An organism that can't manufacture its own food and needs to take nutrients in from outside sources, e.g. a cat
Discussion storyboards are a great way to get your students talking about their ideas in Science. They allow students to critique and evaluate different viewpoints without upsetting other students. This activity can be used at the start of the topic to elicit any misconceptions students may have.
At first, show students a discussion storyboard like the one below. Ask them to look at the problem on the discussion storyboard. It shows four students who all have an idea about the problem in front of them. Students should think about who they think is the most correct and be prepared to explain why that person is correct.
Here are some other ideas to use these discussion storyboards in your lessons.
Students add another cell on the end of the example you’ve given them to explain who they think is correct and why.
Students create their own discussion storyboards to share with peers on the current topic.
Note that the template in this assignment is blank. After clicking "Copy Assignment", add your desired problem and solutions to match the needs of your students.
In this activity students will find examples of different vertebrate groups. Vertebrates all belong to the kingdom Animalia and the phylum Chordata. Vertebrates are a subphylum of chordates that all have a backbone. There are 66,000 known vertebrates found all over the world!
Fish are technically split into separate classes: Agnatha (Jawless fish), Chondrichthyes (Cartilaginous fishes), Placodermi (Armored fishes) and Osteichthyes (Bony Fishes). For the purpose of this activity the classes have been grouped together. Fish are a group of animals that live in the water and all have gills. They don’t have limbs like digits (e.g. fingers and toes). Most fish are cold-blooded although there are a few exceptions.
Great White Shark (Carcharodon carcharias)
Atlantic Cod (Gadus morhua)
Southern Stingray (Dasyatis americana)
This group of animals spends part of their lives on water and land. They are cold-blooded, meaning they cannot regulate their body temperatures. Unlike reptiles and some fish, amphibians do not have scales; they have a skin which allows gases to go through it. Most amphibians have primitive lungs so they can also pass oxygen through their skin into their bloodstream. Most amphibians are metamorphic, meaning they will change their shape and form at some point in their lives, such as from a tadpole to an adult frog.
American Bullfrog (Lithobates catesbeiana)
Palmate Newt (Lissotriton helveticus)
Chinese Giant Salamander (Andrias davidianus)
Reptiles, like amphibians, are nearly all cold-blooded. They are covered in scales and breathe with lungs. Almost all reptiles are oviparous, meaning they lay eggs. Most reptiles have a three chambered heart, with the exception of crocodiles. Most reptiles have four legs, but snakes and some lizards are an exception to this.
Mwanza Flat-headed Rock Agama (Agama mwanzae)
Burmese Python (Python bivittatus)
Saltwater Crocodile (Crocodylus porosus)
Mammals are warm-blooded animals, meaning they can regulate their body temperatures. This allows them to live in many different climates around the world and makes them extremely diverse. All mammals have some hair or fur at some point in their lives, even dolphins and whales! Mammals nurse their young with milk which they produce in mammary glands. Normally, this milk is produced by females except for the Dayak Fruit Bat, where males take on the role. All mammals have four chambered hearts. Most mammals are viviparous, meaning they give birth to live young rather than eggs. Monotremes, e.g. the platypus and echidnas, are the exception to this rule, as both these animals are oviparous.
Common Bottlenose Dolphin (Tursiops truncatus)
Human Being (Homo Sapien)
Livingstone's Fruit Bat (Pteropus livingstonii)
Birds can regulate their internal body temperature like mammals. They are characterized by having a body covered in feathers and a beaked jaw. Most birds have evolved to fly, but there are some that have further evolved to be unable to fly like penguins and ratites. Birds lay hard shelled eggs.
Bee Hummingbird (Mellisuga helenae)
Somali Ostrich (Struthio molybdophanes)
Mallard (Anas platyrhynchos)
For more able students, have them start to list the characteristics of each of the vertebrate classes. Alternatively, have them identify animals from each class in a particular habitat.