Navigating Dichotomous Keys

The video tutorial introduces dichotomous keys, explaining their purpose and how to use them to identify organisms. It begins with lesson objectives and a warm-up using cladograms to differentiate between sharks and ray-finned fish. The main focus is on using dichotomous keys to identify birds and other organisms, with step-by-step examples. The tutorial concludes with practice exercises and instructions for independent work.

What are the two main objectives of the lesson?

• Identify an organism using a dichotomous key and list its characteristics

• Identify an organism using a taxonomy chart and list its characteristics

• Identify an organism using a phylogenetic tree and list its characteristics

• Identify an organism using a cladogram and list its characteristics

What is the main difference between sharks and ray-finned fish according to the cladogram?

• Ray-finned fish have vertebrae, sharks do not

• Sharks have vertebrae, ray-finned fish do not

• Ray-finned fish have a bony skeleton, sharks do not

• Sharks have a bony skeleton, ray-finned fish do not

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-2

What is the first step in using a dichotomous key to identify a bird?

• Count the number of toes

• Observe the bird's tufts

• Observe the bird's feet

• Check the bird's wings

If a bird has webbed feet, what is the next step in the dichotomous key?

• Observe the bird's beak

• Check the bird's wings

• Count the number of toes

• Observe the bird's tufts

What is the scientific name of a bird with webbed feet and four toes?

• Hummingbird

• Penguin

• Owl

• Duck

What is the first step in identifying an organism using a dichotomous key?

• Start at number one

• Start at the last step

• Start at number two

• Start at any step

If an organism has a purple colored body and a pointy hump, what is its name?

• Dearest Humpus

• Dearest Octagos

• Dearest Purpliness

• Dearest Greenus

How do you find the characteristics of an organism if you only have its name?

• Guess the characteristics

• Start at the last step

• Use a different key

• Work the key backwards

What is the name of an organism with a green body and four legs?

• Dearest Humpus

• Dearest Octagos

• Dearest Purpliness

• Dearest Greenus

What should you do if you are confused about your answer when using a dichotomous key?

• Skip the question

• Guess the answer

• Check your answer by working backwards

• Start over from the beginning