30th June 09 (Tue)

Lesson Objective

At the end of the lesson, pupils are able to: • Understand that a streamlined body shape achieves a greater speed. • Show awareness of animals’ adaptations for flight.

Adaptations for Movement

Animals need to move efficiently in order to hunt for food and escape from danger.

We will take a look at how animals adapt to moving in water and in air.

Watch video on “Adaptations Features That Help Animals Survive”

Moving in waterWhen aquatic animals move through water, they experience a force called water resistance that acts against the direction of their movement.

Aquatic animals need to overcome water resistance so that they can move easily through the water.

Direction which the fish moves

Water resistance

They usually have these structural adaptations: • Streamlined body shape• Modified limps• Swim bladder

Streamlined body shapeThe bodies of most aquatic animals are streamlined.

A streamlined body shape is one that is narrow at both ends, and broad in the middle.

This shape enables the animals to swim faster. (E.g. fish, penguin, dolphin)

These animals need to swim fast to catch their prey or swim away from predators to avoid being eaten.

• Aquatic animals have modified (adapted) limps to help them move in water.

Modified limps

• Aquatic animals have modified (adapted) limps to help them move in water.

Modified limps

• Aquatic animals have modified (adapted) limps to help them move in water.

Modified limps

Swim bladder• Besides being able to swim, aquatic animals need to stay

afloat or buoyant in water.

• Most fishes have a swim bladder, which is like a little balloon of air inside the body of the fish.

• The fish can control the depth it wants to float at by varying the amount of air held in its swim bladder.

Fold a paper areoplane that that would travel the farthest.

Identify the design characteristics that are important for flight.

• Lightweight

• Large surface area

• Balanced weight

• A streamlined shape

Moving in air•All flying animals have special adaptations for flight:

Wings

Flight muscles

Streamlined body shape

Hollow bones

Wings• Birds have wings that are very well-developed for flying.

• Most birds can fly but some are much better at it than others.

Wings• Birds that have heavy bodies and do not have well-developed wings cannot fly.

• They include the ostrich, emu, goose, chicken and turkey.

Flight musclesBirds also have strong flight muscles for flapping their wings.

FeathersBirds are the only animals that have feathers. Feathers make light but strong wings, and keep the birds warm.

The warmth provided by the feathers ensures that the flight muscles can work properly.

Streamlined body shape

Just like there is water resistance, there is a force called air resistance that opposes motion in air.

When a bird is flying, its streamlined body shape helps to reduce air resistance.

Hollow bones

Most importantly, birds have bones that are hollow yet strong.

This reduces the bird’s body weight and makes flight easier.

Summary• Structural adaptations are special body parts of an

organism that help it to survive in its natural habitat.

• Body shapes of fishes and birds’ adaptations for flight are structural adaptations.

• Speed of swimming is an important necessity for the survival of some animals. Fishes that can swim fast have streamlined torpedo shapes.

• Animals which can fly are generally lightweight (e.g. birds have hollow bones, bats have slim and light bones), have wings with large surface area, streamlined bodies, powerful muscles to flap the wings and a warm body to keep muscles functioning well.

To do:

• Science Workbook, Pg 23 – 25

• Access Youtube website on ‘Great White Sharks”

• http://www.youtube.com/watch?v=qHnS8_0da6A&feature=PlayList&p=4E6B935168156E06&index=25

• Journal Writing on ‘Great White Sharks”