Transcript Methods of asexual reproduction

Methods of
Reproduction
Types of Reproduction
• There are two main ways in which
reproduction occurs:
– Asexual Reproduction
– Sexual Reproduction
Asexual Reproduction:
requires only 1 parent and the offspring are an
exact copy of the parent---a clone
Asexual Reproduction:
• Organisms that reproduce asexually cannot
develop much variety, because they are
“copying” the original organism exactly.
Methods of asexual reproduction:
Binary fission
Budding
Fragmentation
Binary fission
Single-celled organisms
(Amoeba, paramecium,
euglena) which use asexual
reproduction can do so
simply by dividing into two
equal halves.
This is called binary fission.
• When conditions are good, such as plenty
of water, food, right temperatures, etc.,
binary fission is a very effective way of
producing many, many offspring.
• For example, the cell of a Paramecium
can divide, grow, and divide again in the
space of 8 hours.
Budding- an offspring grows out
of the body of the parent.
offspring
Hydra Budding
Cactus Budding
Budding
In yeasts the cell does
not divide equally in
two halves; instead,
there is a large mother
cell and a smaller
daughter cell.
Yeast - budding
Fragmentation
In this form, the body of the parent breaks
into distinct pieces, each of which can
produce an offspring.
Pieces of coral broken off in storms
can grow into new colonies.
A new starfish can grow from
one detached arm.
Fragmentation- plant cuttings
Some plants can grow from cutting them
up and replanting them.
Green plants are quite sophisticated in
their methods of asexual reproduction.
Offspring may be produced by runners,
bulbs, rhizomes or tubers.
What is sexual reproduction?
• Requiring 2 parents
– male and female
• Offspring are different from the parent
organism because it takes half the DNA
from one parent and half from the other
Sexual Reproduction
• Sexual reproduction produces a greater
chance of variation within a species than
asexual reproduction would.
• This variation improves the chances that a
species will adapt to his environment and
survive.
Sexual vs. Asexual Reproduction
• Asexual reproduction results in offspring
that are genetically identical to the parent
organism.
• Sexual reproduction results in offspring that
are genetically different from the parent
organisms.
DNA – Chromosomes Genes
DNA
•DNA: the chemical inside the nucleus of a
cell that carries the genetic instructions for
making living organisms.
•The scientific name for DNA is
deoxyribonucleic acid.
http://www.ncbi.nlm.nih.gov/
Chromosomes
A chromosome is one of the threadlike "packages" of
genes and other DNA in the nucleus of a cell.
Different kinds of organisms have different numbers
of chromosomes.
Humans have 23 pairs of chromosomes, 46 in all.
Each parent contributes one chromosome to each
pair, so children get half of their chromosomes from
their mothers and half from their fathers.
http://www.ncbi.nlm.nih.gov
Gene
• A gene is the functional and physical unit of
heredity passed from parent to offspring.
• Genes are pieces of DNA, and most genes contain
the information for making a specific protein.
http://www.ncbi.nlm.nih.gov
Genome
• A genome is all the DNA contained in an
organism or a cell, which includes the
chromosomes plus the DNA in mitochondria
(and DNA in the chloroplasts of plant cells).
http://www.ncbi.nlm.nih.gov
Cell division and DNA replication
• Cells divide
• Growth, Repair, Replacement
• Before cells divide, they have to double cell
structures, organelles and their genetic
information
DNA replication – Mitosis & Meiosis
Videos
• Asexual Reproduction/Binary Fission
– https://www.youtube.com/watch?v=DY9DNW
cqxI4
• Budding in Yeast:
– https://www.youtube.com/watch?v=iOvrq6ssy2
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• Regeneration:
– https://www.youtube.com/watch?v=EsCSwVx3
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