Download Sexual reproduction

Reproduction Introduction
Asexual reproduction:
1. The prefix “A” comes from the Greek language and
means without.
2. The term asexual means without to cross which really
doesn’t make sense but it is also defined as without
crossing.
3. Asexual organisms make an exact copy of themselves, like
a photocopy.
4. Is there much variation (different genes) in a group of
paramecia ? No. Paramecia offspring are all identical to
the parent (cell that divides) genetically because there is
no combination of traits or genes.
Reproduction Introduction
Sexual reproduction:
1. Sexual reproduction means to “to cross”.
2. Sexual reproduction means that two parents combine
parts of their genetic material (DNA).The male
contributes a copy of half his genetic material and the
female contributes a copy of half of her genetic material.
3. The “baby” that is born is called the offspring.
4. In a very basic way, the offspring get half their traits
from each parent.
5. Because of the way the male and female copy their own
genetic material and the way they are combined each
offspring is different.
Reproduction Introduction
Circle the correct type of reproduction:
1. Mammal
Sexual Asexual Both
2. Insect
Sexual Asexual Both
3. Fish
Sexual Asexual Both
4. Plants
Sexual Asexual Both
5. Bacteria
Sexual Asexual Both
mixing DNA
Types of
Reproduction
Sexual vs. Asexual
Reproduction
Reproduction
 In order to be considered alive, organisms must
be able to reproduce
 Reproduction is the ability to produce offspring
that are similar to the parents.
 Offspring - the product of reproduction. The
“child” or “baby”.
 There are two possible ways the organisms can
reproduce:
 Asexual reproduction
 Sexual reproduction
Asexual Reproduction
 Asexual reproduction: reproduction where an
organism makes an exact copy of itself and splits
to become two separate organisms
 Asexual reproduction is characterized by:
Only 1 parent
Parent and offspring are identical genetic copies
Copying mistake (genetic mutations) can occur
A small, limited gene pool (little variation)
Requires less energy
Asexual reproducers:

Bacteria

Hydra (simple sea animals)

Microscopic organisms
(paramecium, amoeba)
Types of Asexual Reproduction
•
•
•
•
•
•
Budding
Fragmentation
Propagation
Regeneration
Binary Fission
Others…
Budding
• Process by which a new, duplicate plant or
animal begins to form at the side of the parent
and enlarges until an individual is created.
• Common in some plants and hydra
Fragmentation
• In this type of reproduction, the body of the
parent breaks into distinct pieces, each of
which can produce an offspring.
• Common in some types worms like Planaria
Propagation
• Part of the parent cell is cut off and can
grow into a new individual.
• Common in certain plants.
Regeneration
• If a piece of a parent is detached, it can grow
and develop into a completely new individual.
• It is a common feature in invertebrates like
starfish.
Binary Fission
• Separation of one organism into two new
organisms by mitosis.
• Only in single celled organisms like
bacteria and protists.
Sexual Reproduction
Sexual reproduction: reproduction where two organisms’
genetic information (DNA) combines in a single, new offspring
 Sexual reproduction is characterized by:
Two parents (male and female)
Combination of egg and sperm cells
Genetic information gets mixed
Large gene pool (lots of variation in traits)
Sexual reproducers
Mammals, Fish, Reptiles, Birds,
 Most Insects
 Most Plants
 Large, complex organisms

BOTH Asexual and Sexual Reproduction
• Some organisms can use both types of
reproduction. There are advantages to each
method.
• Most organism switch to the type of reproduction
that is best for their current situation.
• Examples:
– organisms that can regenerate - star fish, newts,
worms
– Some plants – Daffodil, Cactus
– Fungi – Mushrooms
Advantages and Disadvantages of
Asexual Reproduction
ADVANTAGES
• Less energy required
• Don’t need to find a
partner
• Very Quick (Have
several offspring in a
short amount of time)
• Less resources required
DISADVANTAGES
• Need a stable environment
• Sensitive to their
environment
• Limited amount of traits
available
• No mixing of DNA
Advantages and Disadvantages of
Sexual Reproduction
ADVANTAGES
• Don’t need a stable
environment
• Varied genetically
(Many traits to choose
from)
• Mixing of DNA;
endless possibilities of
traits.
DISADVANTAGES
• Need to find a partner
• Requires more energy
• Smaller amount of
offspring
• More resources
needed.