Sexual vs. Asexual
Reproduction
What to take notes on?
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When you see something that is underlined and in a different color…you
should take notes on it.

Don’t take notes on something that looks like this – this is stuff that you
should read and think about, but it’s not stuff you will need to retain or
remember for future lessons or assessments

This is what notes you should write down look like – this is stuff you will need to
copy and make sure you look over on your own time
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You will use this for future lessons and assessments
DNA – what is it and how does it work?
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Every cell in your body has a job – there are over 200 cell types in the human
body…that means over 200 jobs!
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How does each of these cells know exactly what job to do?
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DNA
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Set of instructions or a blueprint for each cell
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Made up of 4 bases (A, G, T, C)
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T <-> A
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G <-> C
DNA coding
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Two sides to DNA double helix – match to each other
Side one - ATG CGT GGT CAG TCG ATA TAT GGC CCC
Side two - TAC GCA CCA GTC AGC TAT ATA CCG GGG
Chromosomes hold all of your DNA
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DNA is packaged tightly and organized into
chromosomes
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Chromosomes hold the needed codes for
characteristics like hair color, eye color, height
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All cells in an organism have the same set of
chromosomes
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Chromosomes exist in pairs
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One from mother, one from father
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Humans have 23 pairs
Each chromosome pair codes for characteristics
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Codes interact with each other – some dominant, some recessive
Purpose of Reproduction
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Produces offspring
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Continues genetic line
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Increases population of the species
Types of Reproduction
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Asexual
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Offspring arise from a single organism
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offspring are genetic copies of the parent
Sexual
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Offspring arise from two parent organisms
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offspring are a genetic mix of half the mother’s DNA and half the father’s DNA
Asexual Reproduction
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Organisms that reproduce asexually:
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Single-cell Organisms
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Bacteria
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Protists
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Amoebas
Some multi-cellular Organisms
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Starfish
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Fungi
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Sea anemones
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Coral
How does Asexual Reproduction work?
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Mitosis – process makes exact copy of DNA
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Cell copies its chromosomes and splits
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Creates a cell exactly like the original
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Parent = Offspring
TWO
IDENTICAL
CELLS
PARENT CELL
COPIES CHROMOSOMES
SPLITTING APART
Video on Asexual Reproduction/Mitosis

Be amazed and enriched by the carefully selected and very important video!
Advantages vs. Disadvantages
ADVANTAGES
DISADVANTAGES
• FAST PROCESS
• LACK OF GENETIC VARIATION
• POPULATION GROWS QUICKLY
• VULNERABLE TO EXTINCTION IF ENVIRONMENT
CHANGES
• ONLY ONE PARENT NEEDED
• no need to find mate
• LITTLE ENERGY REQUIRED
• IF PARENT HAS ISSUE (BAD TRAIT) – OFFSPRING
HAS ISSUE
Sexual Reproduction
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Organisms the reproduce sexually:
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Most:
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Mammals
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Fish
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Reptiles
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Birds
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Insects
How does Sexual Reproduction work?
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Meiosis – process that makes sex cells (“gametes”) – cells that only have half
the chromosomes of the cells of the parents
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Cell copies its chromosomes and splits
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Cells then split AGAIN
Creates 4 cells that have half
the chromosomes of the
original cell
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These 4 cells are called GAMETES
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Sex cells – eggs or sperm
Egg and Sperm come together
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½ + ½ = whole cell
ORIGINAL CELL
FIRST SPLIT
COPIES CHROMOSOMES
SECOND SPLIT
Video on Sexual Reproduction/Meiosis

Be amazed and enriched by the carefully selected and very important video!
Advantages vs. Disadvantages
ADVANTAGES
DISADVANTAGES
• GENETIC VARIATION WITHIN SPECIES
• combination of sperm and egg
creates variety
• REQUIRES A LOT OF ENERGY AND TIME
• LESS LIKELY TO GO EXTINCT
• more likely to have traits that allow for
adaptation
• POPULATION GROWS SLOWLY
• ALLOWS FOR EVOLUTION AND SURVIVAL OF
SPECIES
• HAVE TO FIND/ATTRACT A MATE
Test yourself!
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http://learn.genetics.utah.edu/content/variation/reproduction/