[114]Key points of Unit 3

Unit 3: Activity 1: Is the body structure and function of animals related?

1. Different species of animals have different physical characteristics in order to adapt to the environment.

2. The body structure of different animals is also different, and the body structure of common animals is as follows:

category	Annotation structure
people	Head, torso, limbs
Rabbit	Head, torso, limbs, tail
Frog	Head, torso, limbs
Lizard	Head, torso, limbs, tail
Bird	Head, torso, wings, feet, tail feathers
fish	Head, torso, fins

3. Each animal has unique physical characteristics, and according to these characteristics, we can clearly distinguish each animal.

4. Common animals can be divided into mammals, amphibians, reptiles, birds, and fish.

 

category	Features	Animals are examples
mammals	The mother can secrete milk to feed her young	People, rabbits, dogs, cats, tigers, sheep, brown bears, polar bears, etc.
Amphibians	Lives in water when young; As they grow up, their bodies change in shape and they can live on land and in water.	Frog
Reptiles	The body has a dry crust, scales, or crust on the outside.	Lizards, turtles, snakes, crocodiles, chameleons, etc.
birds	It has two feet and a pair of wings, and its body is feathered.	Green embroidered eyes, sparrows, pigeons, ducks, chickens, owls, ostriches, etc.
fish	It lives in water and has gills, scales, and fins.	Carp, pot-bellied fish, etc.

 

5. The body of different animals has many different structural characteristics, each with different functions.

animals	The function of the constructed feature
Dog	The limbs are about the same length and thickness, and the soles of the feet have meat pads, which are suitable for running and walking.
Rabbit	The hind legs are strong and powerful, and they are good at jumping.
Cats	There are meat pads on the soles of the feet to reduce the impact of jumping and reduce the sound of walking to facilitate hunting.
Frog	The hind legs are thicker and longer, and they are good at jumping. Some frogs have suction cups on their feet, which are easy to adsorb on leaves or branches; Frog feet are mostly webbed and swim.
Lion	The feet have sharp claws that help hunt prey.
Lizard	It has claws on all four limbs that help it climb trees.
Sparrow	Paws on the feet to stand or grasp objects; It has wings and can fly.
Duck	有翅膀，可以飛行；腳上有蹼，可以游水。
fish	There are fins, swinging the fins to swim forward.
Earthworms	The body can stretch and contract and move in the soil.
Turtle	Most freshwater turtle feet are webbed and can swim; Turtles have fin-shaped limbs and can live in the sea for a long time.
Ostrich	has wings, but cannot fly after degeneration; Ostriches have thick and powerful feet that allow them to run fast.

 

Activity 2: Is the body structure of animals related to adaptation to the environment?

1. Animals living in different environments have different structural characteristics to adapt to their living environment. For example, ducks have webbed feet and can live near water. Earthworms live in the soil and use their bodies to stretch and contract to move.

2. Animals need food for growth, and different animals consume different types of food:

animals	Food ingested
people	Drink milk in infancy and feed on various animals and plants when you grow up.
Tiger and lion	Carnivorous, feeding mainly on animals.
Sheep, horses, rabbits	Herbivorous, feeding mainly on plants.
Brown bear	Omnivorous, feeding on small animals and plants.
Sparrow	Omnivorous, preys on small insects and also eats plant seeds.
Frog	Carnivorous, mainly preying on small insects.

3. Animals respond appropriately to environmental changes to adapt to their living environment:

animals	environmental changes	Adaptive reactions
people	Light changes	The eyes adjust their pupil size as the light changes, with smaller pupils when the lights are on and larger when the lights are turned off to adapt to the environment.
	Temperature changes	The skin can feel the change in temperature, and when the temperature drops suddenly, the skin will feel cold and shiver, causing the body to generate heat; When the hand touches something hot, it will quickly retract to avoid injury.
Cats	Light changes	The eyes adjust their pupil size according to the change in light, with smaller pupils in bright areas and larger pupils in dark areas to adapt to the environment.
Earthworms	Light changes	Earthworms like a dark environment, digging earthworms out of the soil, and earthworms will always want to burrow back into the soil.
	Moisture changes	Earthworms like moist soil, but after heavy rains, there is too much moisture in the soil, and it is difficult for earthworms to breathe, but they will burrow out of the soil.

 

Activity 3: What is the magic weapon for the survival of animals?

1. Some animals have a similar color or shape to the environment, making them less likely to be detected to avoid predation or to facilitate predation on other animals.

animals	Ways to protect yourself
Owl	The color and pattern of the feathers are similar to the trunk of the tree, and it is difficult to detect when not moving.
Polar bear	The fur color is the same as that of snow, which makes it easy to track and raid prey on ice.
Sven Howe's Lizard Climbing	The body color is the same as the trunk, helping to hide in the environment.
Tree frog	The body color is the same as the green leaves, and it is not easy to be detected by natural enemies when it is not moving.

2. Some animals have a large difference in body color and environment, which has a warning effect, warning other animals that they are poisonous or not tasty, so as to protect themselves.

animals	Ways to protect yourself
Lionfish	The body is toxic and uses its bright body color to warn other animals not to approach it easily.
Birch butterfly	The larvae have obvious black, yellow and white stripes, and the adults have striking orange wings, warning other animals that they are toxic and uncomfortable to eat.
The Umbrella Festival	There is a distinct black and white body color, warning other animals that they are deadly toxic.
Yellow-banded poison dart frog	The body has obvious yellow bands, and the bright body color is used to warn other animals that they are poisonous and not to approach.

Animals have the same right to live as we do, and we should take good care of them.