Download How are humans adapted for reproduction?

AIM: What is the difference between internal and
external fertilization and development?
Do Now: Using the following diagram, answer the
following questions:
1.Name each structure
2.What is the chromosome number in each structure?
3.Identify process A
4.Identify process B
5.What process forms structures A and B?
Internal Fertilization
External Fertilization
Where does fertilization
take place?
Sperm and egg unite inside
the females body
Sperm and egg unite
outside the females body
Type of environment
Land- why?
No water for the sperm to
swim to the egg
Water- why?
There is water for the sperm
to swim to the egg
Number of eggs produced
Few- why
• Protected inside the
females body
• Parental care
• Eggs are not eaten
• Constant environment
inside the body
• Most of the eggs are
fertilized
Many- why?
• Egg and sperm may not
meet
• Some may get eaten
• Environmental conditions
may change
• No parental care
Examples
Mammals
birds
fish
Embryonic Development
•
The zygote grows and develops into an entire
body.
•
Development can be either INTERNAL or
EXTERNAL, depending on the organism
fertilization
Internal Development
• Embryo develops inside
the females body
• Humans
• Most mammals
External Development
• Embryo develops outside
the females body
Stages of Embryonic Development:
1. The egg cell is fertilized by the sperm cell, forming the
zygote
2. The zygote undergoes cleavage (mitotic cell division)
3. Morula  Blastula (implantation)  Gastrula
Gastrulation
Cells start to differentiate
• Form specialized cells
• Ex: blood cells, nerve cells, muscle cells
• Every cell still contains the same genetic
information
Differentiation
Ectoderm
Outer layer
Mesoderm
Inner layer
Endoderm
Inner layer
Skin, nerve
Muscle, bone
organs
Where does fertilization
usually occur?
In the
fallopian tube
(oviduct)
How are twins formed?
Identical
Fraternal
Number of
eggs released
1
2
Number of
sperm
1
2
Zygote
formation
One zygote
splits during
early
cleavage
Two zygotes
are formed
Genetic
information
Identical
Not identical
What happens after
fertilization?
The developing embryo travels to the
uterus and implants itself in the uterine
lining
1.
2.
3.
4.
5.
Label each structure in the diagram
In which structure are the egg cells produced?
In which structure is estrogen produced?
I which structure does fertilization take place?
In which structure does embryonic development
take place?