Support and movement[1]

Support Support and and

MovementMovement

Support and MovementSupport and Movement

All living things need a support system to All living things need a support system to provide them with support , movement provide them with support , movement and to help them survive in a given and to help them survive in a given environment.environment.

The support system in humans and The support system in humans and animals consists of the skeleton or animals consists of the skeleton or skeletal system and muscular systemskeletal system and muscular system


There are three basic types of support There are three basic types of support system in animals. system in animals.

They are :They are :

a) Exoskeletona) Exoskeleton

b) Endoskeletonb) Endoskeleton

c) Hydrostatic skeletonc) Hydrostatic skeleton


ExoskeletonExoskeleton The skeleton which is outside the body is The skeleton which is outside the body is

called an called an exoskeleton.exoskeleton. example animals such as insects, spiders, example animals such as insects, spiders,

crabs, prawns, snails, and milipedes, the crabs, prawns, snails, and milipedes, the skeleton is a hard, outer skin or shell skeleton is a hard, outer skin or shell outside the body. outside the body.

Support and Movementexoskeleton


ExoskeletonExoskeleton

Invertebrates such as crab, lobster, Invertebrates such as crab, lobster, cockles, mussels, snails, beetles and cockles, mussels, snails, beetles and grasshoppers have a hard outer skin. grasshoppers have a hard outer skin. This is called the exoskeleton.This is called the exoskeleton.

The exoskeleton of garden snails, The exoskeleton of garden snails, mussels and crabs is a hard shell.mussels and crabs is a hard shell.


ExoskeletonExoskeleton The exoskeleton of crabs, lobster, and snails The exoskeleton of crabs, lobster, and snails

consists of mainly of calcium carbonate. This is consists of mainly of calcium carbonate. This is a hard substance that protects the soft body of a hard substance that protects the soft body of the animalthe animal

The outer covering of the exoskeleton of The outer covering of the exoskeleton of insects such as cockcroaches, centipedes, bees insects such as cockcroaches, centipedes, bees and grasshoppers is called the cuticle.and grasshoppers is called the cuticle.

The cuticle is made of chitin. It is hard and The cuticle is made of chitin. It is hard and impermeable to water.impermeable to water.


The function of exoskeletonThe function of exoskeleton1.1. To support the body and give it shapeTo support the body and give it shape2.2. To protect soft body tissues from To protect soft body tissues from

damagedamage3.3. To prevent the body from drying outTo prevent the body from drying out4.4. To provide a surface for the muscles to To provide a surface for the muscles to

attach themselves and to allow attach themselves and to allow movementmovement


EndoskeletonEndoskeleton

A skeleton which is inside the body is A skeleton which is inside the body is called an called an endoskeletonendoskeleton.Human beings, .Human beings, fish, amphibians, reptiles, birds and fish, amphibians, reptiles, birds and mammals have an mammals have an endoskeleton.endoskeleton.


The function of endoskeleton are;The function of endoskeleton are;

1.1. To support the weight of the bodyTo support the weight of the body2.2. To maintain the shape of the bodyTo maintain the shape of the body3.3. To protect the soft organs inside the body To protect the soft organs inside the body

such as the brain, heart, lungs and spinal such as the brain, heart, lungs and spinal cordcord

4.4. To allow the muscle in the human body a To allow the muscle in the human body a place to attach themselves.place to attach themselves.

5.5. To enable the limbs to moveTo enable the limbs to move


Hydrostatic skeletons.Hydrostatic skeletons.

Some invertebrates such as earthworms, Some invertebrates such as earthworms, leeches and caterpillars maintain their leeches and caterpillars maintain their shape by the pressure of the liquid inside shape by the pressure of the liquid inside them. These organisms have them. These organisms have hydrostatic hydrostatic skeletons.skeletons.


The hydrostatic skeleton is a muscular The hydrostatic skeleton is a muscular wall that encloses the body cavity of the wall that encloses the body cavity of the animal.animal.

The high pressure acts on the inner walls The high pressure acts on the inner walls of the animal’s body to support its body of the animal’s body to support its body and maintain its shapeand maintain its shape

The human support systemThe human support system

1.1. The human skeleton is made up of 206 bones.The human skeleton is made up of 206 bones.

2.2. The main parts of the human skeletal system The main parts of the human skeletal system are the are the skull , backbone, ribs, girdles and limbs.

a) The skull protects the braina) The skull protects the brain

b) The backbone supports the upper part of b) The backbone supports the upper part of

the body and also protects the spinal cord. the body and also protects the spinal cord.

The arrangement of the bones allows the The arrangement of the bones allows the

backbone to turn and twist.backbone to turn and twist.

The human support systemThe human support system

c) The c) The pectoral girdle supports the head and supports the head and the armsthe armsd) The d) The pelvic girdle supports the whole supports the whole weight of the body. It also protects weight of the body. It also protects certain organscertain organse) The e) The limb bones allow the hands and legs allow the hands and legs to move easilyto move easily

Support in land vertebratesSupport in land vertebrates


2. The backbone of four - legged land vertebrates such as 2. The backbone of four - legged land vertebrates such as the camel and the horse either curve upwards or the camel and the horse either curve upwards or downwards. The curve enables the backbone to downwards. The curve enables the backbone to withstand the heavy load acting on the animalwithstand the heavy load acting on the animal

3. Big land animals such as elephant and the rhinoceros 3. Big land animals such as elephant and the rhinoceros need strong and big pectoral and pelvic girdles to need strong and big pectoral and pelvic girdles to support their body weightsupport their body weight

4. Big animals that have short legs with larger cross 4. Big animals that have short legs with larger cross sections are more stable and can also support a sections are more stable and can also support a heavier load.heavier load.


The deer and antelope with hollow long The deer and antelope with hollow long bones can move faster. This is bones can move faster. This is especially important to vertebrates such especially important to vertebrates such as birds.as birds.

Hollow bones are stronger and lighter Hollow bones are stronger and lighter than compact bones. Therefore, land than compact bones. Therefore, land vertebrates benefit from the strength of vertebrates benefit from the strength of their hollow bones without having bear their hollow bones without having bear the extra weight of solid bones.the extra weight of solid bones.

Support in aquatic vertebratesSupport in aquatic vertebrates

1.1. The support system of aquatic vertebrates The support system of aquatic vertebrates is not same as land vertebrates because life is not same as land vertebrates because life in water is very different from life on land.in water is very different from life on land.

2.2. Aquatic vertebrates such as whales and Aquatic vertebrates such as whales and dolphins have smaller and lighter dolphins have smaller and lighter endoskeletons than land vertebrates. endoskeletons than land vertebrates.

3.3. This is because a large part of their body This is because a large part of their body weight is supported by water buoyancy. weight is supported by water buoyancy. Water buoyancy helps aquatic animals to Water buoyancy helps aquatic animals to move in water.move in water.



4. 4. The pelvic girdles of many aquatic The pelvic girdles of many aquatic vertebrates are very small of non-existent. vertebrates are very small of non-existent. They are adapted only for swimming in They are adapted only for swimming in water.water.

5. Whales have small skeletons when 5. Whales have small skeletons when compared to their body size because a compared to their body size because a large part of their body weight is supported large part of their body weight is supported by water buoyancy.by water buoyancy.

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Support and movement[1]