Heredity and reproduction
Heredity
Reproduction in plants
Reproduction in animals
In the living things there is a long and complex substance called DNA
Which is found in the nucleus of a cell
Contains many sections of information
That determine what characteristics are inherited by the young from their parents
These sections of information in the DNA are called genes
Characteristics which are determined by genes are called traits
Each gene determines a specific trait
The passing on traits from parents to young is known as heredity
Inherited traits
Visible
Visible in humans
Eg
Type of earlobe
Type of chin
Ability to roll tongue
Freckles
Type of thumb
Height
Colour of hair
Colour of eyes
Plants
Color of flower
Type of skin of fruit
Shape of fruit
Color of fruit
Type of leaves
Not Visible
Plants
Animals
Traits that are unique in each of us
Example
Fingerprints
Environmental conditions may also affect the development of inherited traits
Family tree
A family tree shows how a family member is related to another in the same or different Generations
A family tree is useful to show
how inherited traits are passed down from generation to generation
Hereditary diseases are caused by
defective genes when a family has heredity diseases
we can use the family tree to trace how the disease is passed on and which family members are affected
In flowering plants flowers are important for sexual reproduction because they produce male and female reproductive cells
When the male and female reproductive cells drawing together the flowers that float into fruits and seeds
the seeds are produced new plants in suitable conditions
Two types of flowers in sexual reproduction
Some flower have either the male or the female reproductive parts in them
Some flowers have both male and female parts in them
Structure and function of flowers
Sexual organs of a flowering plants are found in flowers
Consist of anther filament petals sepal stigma Style ovary and ovule
Male
Female
anther
Stigma
Filament
Produces pollen grains
Holds the anther up
style
ovary
ovule
Receives pollen grains on its sticky surface
Positions the stigma to receive pollen grains
Connect the stigma to the ovary
Produces egg cell which are contained in the ovule
Protects ovule or ovules
Develops into a fruit after fertilization has taken place
Contains the egg cell
Develops into a seed after fertilization has taken place
Insect pollinated flowers and wind pollinator flowers
Pollination is the transfer of pollen grains from the anther to the stigma
This process can take place in the following ways
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Dimples
Intelligence
Blood group
Quality of fruits
diseases
diseases