Hello Everyone My name is Khalid and I will be your science teacher .
Today we are going to study something interesting called Structures:
Can anybody tell me what are structures ??
Well Structures are like parts that form together making a system.
So how does structures have to do with science and organisms??
Structures help all organisms and living things to function survive, grow get energy and stay healthy.
All Living organisms have internal and external structures
Can anyone tell me some examples??
Well internal structure as the heart it pumps blood to all body organs
An external structure could be the eyes or skin eyes helps us to see so the structure helps us to function
if we cant see we will not be able to walk around am I right ?
Today we are going to talk about 5 structures
1.Physical Structures
2.Structure for support
3.Structure for Reproduction
4.Structure for Circulation.
Physical structure:
In plants for example stems support the plant but all stems are
covered with bark (which is similar to our skin as humans ) it has
an outer covering that peels so that new tree growth can
expand outward as we said before that structures help living
things to grow and function so here bark helps the plants to
grow.
Let’s take an example of a reptile as a snake snakes shed their
skins as they grow.
Physical Structures are different in shape even if they do similar
functions.
Let’s take an egg for example the egg covering is really delicate
and needs to be hidden from predators.
In Contrast the plant seeds have tough covering that helps it to
survive. (even if swallowed by an animal)
Why tough coverings it helps them expand and move from place
to another.
The seed develops inside tasty fruits which animals love to eat
and I think you like fruits to.
Animals eat fruits that contains seeds and carry them to places
that these seed may grow better.
So to make it clear it helps the organisms or living things survive
and by moving to places where more water for example or
sunlight these seeds may grow faster so the structure helped
them to grow in a better place.
Structures for support.
Can anyone tell me an example?
Well humans and fish have internal
skeleton this skeleton helps protect and
support their bodies.
Can you touch your heart or your brain?
No because the skeleton surrounds the
organs to protect them from damage.
Exo external
Other animals have exoskeleton such as
turtles the turtle shell is considered an
exoskeleton it protects the turtle its hard
and found outside of the body.
Plants have stems that support them to
stretch towards sunlight help them grow
and also hold the weight of fruits and
leaves.
Some plants have wood and branches in
their stems for additional support.
Structures for reproduction.
What is reproduction?
It’s a process where Living things can make other living things
similar to themselves.
To make other living things similar to them one important things
must occur first and it is called fertilization of the egg. Let me show
you examples to understand this process.
Lets start with plants does anyone knows how does a plant
reproduce?
Well lets take the cherry plant as an example as you can see in
page 111 the plant has a flower that contains pollen when a pollen
is carried away by wind to another cherry flower the receiving
flower becomes fertilized. Once it is fertilized it grows to another
cherry that has a seed. The seed has the nutrition and protective
covering ( physical structure as we said before) if this seed falls on a
good soil a new cherry plant grows, and this is simply the meaning
of reproduction.
Animals Reproduce in a different eay for example the female fish it
lay eggs under rocks in water. Then the male fish fertilizes these
eggs the organism grows inside the egg which have a source of
nutrition and a protective cover.
In other mammals males have structures that fertilizes the eggs
inside the body of the female.
Structures for Respiration
In order for plants and animals to live and survive they need to
exchange gases as Co2 and oxygen with their environment.
Animals such as turtles and humans take in their air through the mouth
or nose and breath using their lungs.
Other animals such as insects lets say a bee for example take in air
through structures called spiracles.
Spiracles are holes in the insect body.
Most fish take in oxygen from the water through their gills.
So as we said animals can get oxygen by 3 ways or 3 different structures
1.Lungs 2. Spiracles 3. Gills
Plant Have structures that are similar to spiracles on an insect body .
But in plants the holes are called stomata and are located on the leaves
of the plant.
The carbon dioxide in the air enters the plant through the holes on
their leaves which are called ? Stomata
During a process called photosynthesis the plant uses energy from the
sun and Co2 from the air to make sugar or food.
Oxygen is also produced in this process and exits through the stomata.
Structures for circulation.
Some plants have a circulatory system similar to those of humans this system is
called (the vascular system) tissues in the vascular system transport the sugar made
in the leaves to the roots for storage. The sugar that the plant made by the process
of photosynthesis with the help of the respiration structures.
So to sum up all what we had said
Structures helps living things to survive grow reproduce and get energy.
There are different types of structures
Physical: to survive and grow (Shell, Skin, Bark on stems of trees)
Support structures: To protect organs in the living things and to support them)
Reproductive structures: to help living things make living things that are similar to
them.
Respiration: To help organisms get food and energy
3 types that helps living things get oxygen from environment
Lungs Gills and spiracles
While in contrast to spiracles plants have stomata on their leaves which enters Co2
and helps in the process of photosynthesis and sugar production.
Circulation: Helps living things to transfer the food they produced and other
minerals and oxygen or carbon dioxide