Who lives in the ocean? - Lesson Four
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La durée de la leçon est: 45 minIntroduction
Lesson 4 – How long do sea turtles live?
This lesson covers:
What features do sea turtles have?
What are the different sea turtle species?
What do sea turtles eat?
Learning activities:
Discuss sea turtle features.
Understanding how sea turtles breathe and drink water.
Writing and discussion exercises on what has been learned.
Instructions
Time: 45 minutes
Contact: education@seashepherdglobal.org
© Sea Shepherd 2022
Éléments de cette leçon
Slide 1 - Diapositive
This lesson is provided by Sea Shepherd. Sea Shepherd is a marine conservation organisation with a mission to protect the ocean and marine wildlife. Sea Shepherd works globally on a range of issues impacting the ocean, running numerous direct action campaigns each year. Sea turtles are one species that Sea Shepherd is fighting to protect.
Slide 2 - Diapositive
During the lesson we will use these icons to identify the learning actions.
Slide 3 - Diapositive
Sea turtles have existed for over 100 million years, since the time of the dinosaurs.
Today they are disappearing from the ocean as their numbers reduce. We have to help protect them.
Facts about sea turtle shells:
Shells are made of two layers, one of bone and one of keratin scutes (what fingernails are made of).
Scutes are like big scales, they are what make the pattern on the back of the sea turtle.
The leatherback turtle doesn’t have scutes, it has a leathery skin.
A sea turtle cannot retract its head into the shell.
Today they are disappearing from the ocean as their numbers reduce. We have to help protect them.
Facts about sea turtle shells:
Shells are made of two layers, one of bone and one of keratin scutes (what fingernails are made of).
Scutes are like big scales, they are what make the pattern on the back of the sea turtle.
The leatherback turtle doesn’t have scutes, it has a leathery skin.
A sea turtle cannot retract its head into the shell.
Slide 4 - Diapositive
Use the image to help explain the sea turtle life cycle.
During nesting season females will come ashore to lay eggs every couple of weeks. They use their flippers to dig a hole to lay the eggs in. They can lay any number up to 200 eggs, called a clutch. After the eggs have been laid, the sea turtle fills the egg chamber with sand using her hind flippers, and then fills the body pit where she has been laying using all four flippers. So, no one knows where she has laid her eggs.
The sand filled chamber keeps the eggs warm until they hatch. The temperature of the nest during this time determines whether the babies will be boys or girls. Warm, dark sand produces mostly females and cool, white sand results mostly in males.
It takes about 7 to 12 weeks for the eggs to hatch, but it then takes the babies (hatchlings) two or more days to reach the surface, usually at night, where they emerge as a group.
They then head out to sea, where they feed and grow, When they are bigger they return closer to shore.
During nesting season females will come ashore to lay eggs every couple of weeks. They use their flippers to dig a hole to lay the eggs in. They can lay any number up to 200 eggs, called a clutch. After the eggs have been laid, the sea turtle fills the egg chamber with sand using her hind flippers, and then fills the body pit where she has been laying using all four flippers. So, no one knows where she has laid her eggs.
The sand filled chamber keeps the eggs warm until they hatch. The temperature of the nest during this time determines whether the babies will be boys or girls. Warm, dark sand produces mostly females and cool, white sand results mostly in males.
It takes about 7 to 12 weeks for the eggs to hatch, but it then takes the babies (hatchlings) two or more days to reach the surface, usually at night, where they emerge as a group.
They then head out to sea, where they feed and grow, When they are bigger they return closer to shore.
Slide 5 - Diapositive
There are 7 main species of sea turtles. These are some facts you can share with students.
Green turtles don’t get their name from the colour of their shell, which is anywhere from brown to olive. They’re called green turtles because they have green skin. They have a hard shell. They live mainly in shallow water near the coast, where they find lush sea grass beds to feed on.
Green turtles will live up to 80 years if not longer. Most of the time they will stay at sea, and only ever come to shore to nest. They grow to 1.5m (4.9feet) long and weight up to 300kg (660lbs).
The Hawksbill turtle is really interesting; they get their name from the sharp, curved beak that looks like a ‘hawk’s beak’. The beak allows it to get food from crevices in coral reefs. The shell is very colourful and has a saw-like edge to it.
Hawksbill turtles can grow up to 70kg (154 pounds) and grow to around 90cm (3 feet).
They can live up to about 50 years. Hawksbills are the most endangered of all sea turtles.
Green turtles don’t get their name from the colour of their shell, which is anywhere from brown to olive. They’re called green turtles because they have green skin. They have a hard shell. They live mainly in shallow water near the coast, where they find lush sea grass beds to feed on.
Green turtles will live up to 80 years if not longer. Most of the time they will stay at sea, and only ever come to shore to nest. They grow to 1.5m (4.9feet) long and weight up to 300kg (660lbs).
The Hawksbill turtle is really interesting; they get their name from the sharp, curved beak that looks like a ‘hawk’s beak’. The beak allows it to get food from crevices in coral reefs. The shell is very colourful and has a saw-like edge to it.
Hawksbill turtles can grow up to 70kg (154 pounds) and grow to around 90cm (3 feet).
They can live up to about 50 years. Hawksbills are the most endangered of all sea turtles.
Slide 6 - Diapositive
The olive ridley sea turtle has an olive green shell and grows to around 70 cm (2.5 feet). It weights around 45kg (100pounds). They live to over 50 years.
The kemp ridley has a dark green shell and a white or yellowish underside. It grows up to 66 cm (2 feet) and weights up to 50 kg (110 pounds). They live up to 50 years.
The kemp ridley has a dark green shell and a white or yellowish underside. It grows up to 66 cm (2 feet) and weights up to 50 kg (110 pounds). They live up to 50 years.
Slide 7 - Diapositive
Loggerhead sea turtles get their name from the shape of their head. They have a large head and a reddish brown shell and live to around 60 years.
They grow up to around 110 cm (3.5 feet) and weight around 170kg (375 pounds).
Leatherback sea turtles have a thin layer of tough skin over the shell that gives it the appearance of leather. They are the biggest of the sea turtles. They grow up to around 183cm (6 feet) and weight up to 500kg (1,100 pounds).
Flatback sea turtles get their name from the shape of their shell, which is flat compared to other sea turtles. They grow to around 99cm (3.25 feet) and weight around 90kg (198 pounds). Estimated they can live up to 80 years.
They grow up to around 110 cm (3.5 feet) and weight around 170kg (375 pounds).
Leatherback sea turtles have a thin layer of tough skin over the shell that gives it the appearance of leather. They are the biggest of the sea turtles. They grow up to around 183cm (6 feet) and weight up to 500kg (1,100 pounds).
Flatback sea turtles get their name from the shape of their shell, which is flat compared to other sea turtles. They grow to around 99cm (3.25 feet) and weight around 90kg (198 pounds). Estimated they can live up to 80 years.
Slide 8 - Diapositive
Young sea turtles spend their early years floating on the ocean current, so they tend to eat small sea creatures and algae.
Once they get older sea turtles move closer to shore. The green sea turtle eats mainly sea grass, kelp and algae from the seabed, but will also eat other creatures, like the box jellyfish.
Other species will eat a mix of sea creatures like sea sponges, coral, sea worms, starfish, shrimp/prawns, jellyfish and squid.
Once they get older sea turtles move closer to shore. The green sea turtle eats mainly sea grass, kelp and algae from the seabed, but will also eat other creatures, like the box jellyfish.
Other species will eat a mix of sea creatures like sea sponges, coral, sea worms, starfish, shrimp/prawns, jellyfish and squid.
Slide 9 - Vidéo
Show this video of sea turtles, see if you can spot the different sea turtle species: https://www.youtube.com/watch?v=UdXQFm33kvQ
Slide 10 - Diapositive
Cet élément n'a pas d'instructions
Slide 11 - Diapositive
Refer Teachers Guide for Learning Activities.
