Who lives in the ocean? - Lesson Two

Lesson 2 - How do sharks swim?
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Social StudiesHistory+31st,2nd Grade

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Introduction

Lesson 2 – How do sharks swim? This lesson covers:  How do sharks move?  What do sharks eat?  How do sharks hear and smell? Learning activities:  How electroreception works.  Understanding how big sharks are – comparing sizes.  Writing and discussion exercises on what has been learned.

Instructions


Time: 45 minutes

Contact: education@seashepherdglobal.org
© Sea Shepherd 2022

Éléments de cette leçon

Lesson 2 - How do sharks swim?

Slide 1 - Diapositive

This lesson is provided by Sea Shepherd.  Sea Shepherd was founded in 1977 and is a marine conservation organisation working to protect the oceans and marine wildlife.  Sea Shepherd works globally on a range of issues impacting the oceans, running numerous direct action campaigns each year.  The protection of sharks is one area Sea Shepherd is working in.
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Slide 2 - Diapositive

During the lesson we will use these icons to identify the learning actions.
Introduction to IUU fishing and the impact of overfishing.
How do sharks move?

Slide 3 - Diapositive

Sharks have been on this planet for over 450 million years. That is well before even dinosaurs existed.

There are currently over 400 species of sharks. Sadly, one out of three shark species is facing extinction, which means they are disappearing from our ocean.

Ask the students what they know about sharks. How do they move through the water?

The shark’s fins help it to move through the water and give it balance.
They have a number of different types of fins. (See diagram)
Without fins the shark would sink to the ocean floor and drown.

Slide 4 - Vidéo

This optional video shows how sharks use their tails to push them along and their fins: https://youtu.be/U2x8sM_QSow
Introduction to IUU fishing and the impact of overfishing.
Shark lifecycle

Slide 5 - Diapositive

Use the image to explain the shark life cycle.

Ask students if they know what a baby shark is called?  Answer: It’s called a pup.
All sharks hatch their young in eggs. Most sharks, like the great white shark, hatch the egg inside mum, and the baby develops until it is born.

Other species of shark lay eggs that they hide in between rocks or coral to protect them until they are ready to hatch.

Introduction to IUU fishing and the impact of overfishing.
Where do sharks like to live?

Slide 6 - Diapositive

Sharks prefer to live in warmer waters, but some have adapted over the years to live in cooler waters. Most likely you won’t find sharks somewhere as cold as the Artic (North pole) or Antarctica (South pole).  Some sharks like to live along the coastline, but others live out in the open ocean.
Introduction to IUU fishing and the impact of overfishing.
What do sharks eat?

Slide 7 - Diapositive

Ask students: “What do you think sharks eat?”

Most sharks are carnivores. Carnivores mean they like to eat other animals. Sharks will eat fish, dolphins, whales, seals, sea turtles and sea birds. Most sharks will find easy targets of sick and weak fish, or what they can find on the ocean floor that has already died.

Did you know that shark teeth are embedded into their gums, rather than bone like ours.  We have one row of teeth, sharks have several rows of teeth.  A shark can lose a tooth every 8 - 10 days. When they lose a tooth a new one moves up from the row behind.

But there are also sharks that eat by filter feeding. Like some whales they open their mouths and filter tiny animals from the water, like plankton, shrimp and small fish.  

There are only 3 species of shark that filter feed – whale sharks (which is the largest shark species), basking sharks and megamouth sharks.  

Introduction to IUU fishing and the impact of overfishing.
How can sharks hear and smell?

Slide 8 - Diapositive

Sharks can hear really well. They have millions of hair cells in their ear that help them sense vibration in the water. This allows them to detect sounds from far away.

Sound travels further under water so sharks can hear from long distances away. Sharks can detect the movement of a fish or marine animals splashing around in the water.

Which is why it is not a good idea to go in the water, when sharks are in the area, if there are seals or fish schools in the area. The shark will hear the noise of the fish and seals and come to investigate looking to see if there is anything to eat.

Sharks have an amazing sense of smell and can detect blood in the water miles away. They can use this to seek out injured marine wildlife to feed on.

Which is why we shouldn’t go swimming near people who are fishing. The smell of the fish will attract the sharks.

Slide 9 - Vidéo

This video shows you three types of sharks - scalloped hammerhead sharks, tiger sharks and white sharks.
https://www.youtube.com/watch?v=GyHMo0ZcoJc

www.seashepherdglobal.org

Slide 10 - Diapositive

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LEARNING ACTIVITIES

Slide 11 - Diapositive

Refer Teachers Guide for Learning Activities.