Download Asexual Reproduction - Effingham County Schools

Reproduction
All Systems Go…
1. How does the body grow? Do cells get
larger as your body increases in size?
2. What do bone cells, muscle cells, and
nerve cells have in common?
All Systems Go…
1. How does the body grow? Do cells get larger as
your body increases in size?
1. Growth occurs when cells divide to create new cells.
Your body always has the same size cells as you
grow you just have more of them.
2. What do bone cells, muscle cells, and nerve cells
have in common?
2. All cells in the body are all descendants of the first cell.
All Systems Go…
3. What is a zygote and when is it formed?
4. What is a blastocyst and when is it
formed?
All Systems Go…
3. What is a zygote and when is it formed?
3. A zygote is the first cell of a person. It is
formed when a sperm fertilizes an egg during
reproduction.
4. What is a blastocyst and when is it
formed?
4. A blastocyst forms by the end of the first
week. It is a ball of cells.
All Systems Go…
5. When will the embryo’s cells begin to
become different types of cells?
6. During the third week, three layers of cells
form in the embryo. What do each of these
three layers become?
All Systems Go…
5.
When will the embryo’s cells begin to become different
types of cells?
5. Between the 2nd and 3rd weeks of development the
embryo’s cell will begin to become different types of
cells like muscle and nerve cells.
6.
During the third week, three layers of cells form in the
embryo. What do each of these three layers become?
6. The top layer will become the brain, spinal cord, and
the backbone. The middle layer will become the heart
and the blood vessels. The inner layer becomes the
respiratory and digestive systems.
All Systems Go…
7. When will the embryo’s heart begin to beat?
7. The heart begins to beat by the 4th week.
8. Describe the importance of cell division? (Why is
it important for cell to divide?)
8. Cells must be able to divide for the body to grow. Cells
must also divide to help the body repair injuries,
replace old cells, and replace worn out cells.
Asexual Reproduction
• Examples of organisms that reproduce
asexually
– Hydra
– Sea Star
– Strawberry
– Archaebacteria
– Eubacteria
– Euglena
– Paramecium
– Yeast
9
Asexual Reproduction
• Requires only one parent
• Offspring have 100% the same DNA as the parent.
– In other words, the offspring are exact “clones” of the
parent.
– Most unicellular organisms reproduce this way.
– Movie
10
Binary Fission- asexual
reproduction that
occurs in single
celled organisms in
which genetic
material is copied
and one cell divides
into two identical
daughter cells.
EX: happens in bacteria,
amoeba, some algae
Budding- Parent
produces a bud that
detaches and develops
into offspring which is
identical to parent
Ex: happens in yeast,
hydra, corals
Asexual Reproduction
• Budding
– Hydra
• Movie
Budding is a means of
asexual reproduction
whereby a new individual
develops from an
outgrowth of a parent,
splits off, and lives
independently.
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FragmentationFragmentation is a form of
asexual reproduction where
a new organism grows from
a fragment of the parent.
Each fragment develops into
a mature, fully grown
individual. Ex: Starfish,
flatworms, and some fungi.
Sexual Reproduction
• Examples of organisms that reproduce
sexually
– Chickens
– Iguanas
– Lobsters
– Sharks
– Humans
– Butterflies
– Sunflowers
– Roses
18
Sexual Reproduction
Type of reproduction in which male and
female reproductive cells combine to form
new offspring with genetic material from
both parents.
***Offspring has genetic material from each parent
which creates- Offspring NOT identical to parent!
(genetic variation)_
Sexual Reproduction
• Happens 2 ways
– Internally (inside)
• The egg is fertilized by sperm inside the female
– Mammals, birds, reptiles, insects, spiders
– Externally (outside)
• The egg is fertilized by sperm outside the female
• The female lays the eggs and then the male
fertilizes them.
– Fish and some amphibians
– Plants and fungi (pollen and spores)
20
Sexual Reproduction in Animals
• involves specialized sex cells called gametes
• the union of a male and female gamete results in
the formation of a zygote that develops into a new
individual
Sexual Reproduction
in Plants Female Parts
Male Parts
(Pistil)
•Involves specialized cells called gametes
•The union of pollen (male gamete) + ovule (female gamete) = results
•Some Organisms do both kinds of
reproduction
• most plants that produce seeds (sexual
reproduction) can also reproduce asexually by
things like cuttings or runners
• this gives them an advantage for survival
sponges and hydra
mosses
Which is Better?
It depends!
Asexual Reproduction
• advantages
– does not require special
cells or a lot of energy
– can produce offspring
quickly
– in a stable environment
creates large, thriving
population
• disadvantages
– limited ability to adapt
– face massive die-off if
environment changes
Sexual Reproduction
• advantages
– lots of variation within a
species
– able to live in a variety of
environmental settings
– able to adapt to changes in
the environment
• disadvantages
– needs time & energy
– produce small populations
Make a Venn Diagram
Asexual Reproduction
Sexual Reproduction
Both
Types of
reproduction
in living
organisms
Pass DNA
from parent
to offspring
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Ever think about how things
grow?
•
•
•
•
How do your fingernails grow?
How does your hair grow longer?
How does a flower get taller?
How does the mycelium of a fungus reach
farther?
Where does this new material come from?
III. Cell division is a process by which a cell
divides into two or more cells, called
daughter cells.
***Your body is constantly making new cells
to replace old ones!
Cell Division
A. Mitosis- Division of the nucleus in
eukaryotic cells in which each cell
receives a copy of the original
chromosome.
1. Chromosome- organized structure of DNA
and protein that forms in the cell nucleus
during cell division
2. Homologous chromosome- chromosomes
with matching information.
Remember:
DNA is found
in the nucleus.
It is organized
into a
chromosome
before it is
copied.
2. Homologous chromosomes
a. Cells must copy the genetic information in
the nucleus before it divides into two
nuclei.
B. Meiosis – division of the nucleus in
eukaryotic cells in which each cell receives
half a set of genetic information. Meiosis
results in the production of egg or sperm
cells.
DNA is copied and
condenses to form
chromosomes
The chromosomes line up
along the center of the cell
The chromosomes are
pulled apart to opposite
sides of the cell
The cell
divides
Plants grow from the tips out by
constantly making new cells!
Cell Division