species discovery walt: classify living things using a dichotomous key

Species Discovery

WALT: Classify living things using a dichotomous key


Diversity of Life

• Nobody actually knows!

• Estimates range between 3 - 100 million different species.

• Latest prediction: = 8.7 million

• Scientists have described around 1.75 million species, so there are lots of species still to find!

How many species are there on Earth?

‘Mr Burns’ beaked toad (Rhinella sp. nov.)

Discovered 2010


• Scientists are finding new species all the time.

• Some scientists plan expeditions to remote and unexplored places to try and discover species that have never been seen before.

• In tropical rainforests, scientists can discover hundreds of potential new insect species in a single tree!

• Most (but not all) newly discovered species are small, from microscopic bacteria to insects and other small organisms. Why do you think this might be?

Species Discovery

Caquetá titi monkey (Discovered 2008)


What is a newly discovered species?

• A species that is completely new to science.

Reef manta ray Giant manta ray

Long-nosed tree frog(Discovered 2011)

• A species previously described which is found to be a different species .

OR


Newly discovered species on ARKive

Psychedelic frog fish (Histiophryne psychedelica)

Pitcher plant (Nepenthes holdenii)

Leaf chameleon (Brookesia micra) Kipunji (Rungwecebus kipunji)


Why do scientists want to find new species?

• Humans depend on plants, animals and healthy ecosystems for fresh air, clean water, food and many other ‘services’.

• Finding new species could lead to the discovery of new ways that plants, animals, and even bacteria can be useful to humans in future, for example in medicines or as a new crop for food.


How do scientists know if they have found a new species?

• Scientists need to be sure that new species have not already been described by another scientist somewhere else, otherwise it could lead to a lot of confusion!

• How do you think they do this?


Classifying species

• All plants and animals can be divided into groups by looking at the similarities and differences between them.

• This is called classification.

• This process of grouping species so that they may be classified and named is called taxonomy, and scientists who do this are called taxonomists.


How do scientists classify species?

E.g. Horseshoe crab

• Anatomically it looks like a crab.• Genetically it is more closely related to spiders!

They organise living things into groups based on: - Anatomy (how it looks)

- Genetics (its DNA)


Classifying animals• Animals can be split roughly into two groups

– Species with a backbone known as vertebrates– Species without a backbone known a invertebrates

Vertebrates include all mammals, birds, reptiles,

fish and amphibians.

Invertebrates include insects, spiders, snails and jellyfish (and many more groups of

species!)


Using classification keys

Does it have hair?

Does it have feathers?

Does it fly?

Osprey Kakapo

Yes

No

Bongo

Yes

No

NoYes

Green iguana


Class Activity 1Identifying newly discovered amphibians

• You are a scientist that has discovered 9 new amphibians. Now you just need to work out which species they are!

• Look at the photographs and use the classification key to help you find out the species’ names.

• Write the names of each species underneath the photograph on your worksheet.


Class Activity 2Make your own classification key

• You have been given pictures of different species.

• Look closely at each species and identify their key features – what makes them different from the other species in your pictures?

• Construct your own dichotomous key that would allow another person to be able to identify each species.


PlenaryCheck a friend’s classification key


PlenaryCheck a friend’s classification key


Peacock

Marbled WhiteChaffinch

Yellow hammer

species discovery walt: classify living things using a dichotomous key

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