Asexual and Sexual Reproduction I can identify the difference between sexual and asexual reproduction.

QW#6 What is the difference between sexual and asexual reproduction?

State Standards 6th Grade Life Science 4 6th Grade Life Science 5 Recognize that an individual organism does not live forever; therefore reproduction is necessary for the continuation of every species and traits are passed onto the next generation through reproduction 6th Grade Life Science 5 Describe that in asexual reproduction all of the inherited traits come from one single parent 6th Grade Life Science 6 Describe that in sexual reproduction an egg and sperm unite and some traits come from each parent, so the offspring is never identical to either of its parents 8th Grade Life Science 1 Describe that asexual reproduction limits the spread of detrimental characteristics through a species and allows for genetic continuity

Reproduction There are about 1.5 million different types of living species known Some reproduce sexually, asexually, or both

Purpose of Reproduction To make sure a species can continue. Definition: Reproduction is the process by which an organism produces others of its same kind.

Asexual Reproduction Asexual reproduction= is a process that involves only one parent and produces offspring that are identical to the parent Advantage- asexual reproduction limits the spread of detrimental characteristics Disadvantage- is asexual reproduction the organism can not adapt to change in the environment

1st Type of Asexual Reproduction Budding is another form of asexual reproduction where a growth of a copy of the adult buds from the adult itself until the bud breaks off and becomes its own organism This happens in yeast Very Common in Plants

Budding Example Fungi are eukaryotic organisms. They are also saprophytic (this means they get their food from dead organic matter) Fungi can be multicellular or unicellular (yeast) Some are parasitic (ringworm, athlete’s foot)

Budding Example Yeast Yeast are unicellular fungi that reproduce by budding Budding occurs rapidly under ideal conditions (mixed with sugar and water in warm temps)

2nd Type of Asexual Reproduction Fission (Binary) is another form used by some single-celled organisms such as bacteria or amoeba Becoming two by division of the complete organism. The organism divides by mitosis to make a new cell

Protists Protists are single-celled eukaryotic organisms Protozoans are named b/c they are “animal-like” and actually resemble eukaryotes in the way they work than prokaryotes like bacteria Ex: Paramecium can reproduce asexually by fission or sexually by conjugation

3rd Type of Asexual Reproduction Regeneration The ability to restore lost or damaged tissues, organs or limbs. It is a common feature in invertebrates, like worms and starfish.

Sexual Reproduction Asexual Reproduction – genetic material of one individual is passed onto the next Sexual Reproduction – genetic material of two individuals are combined In sexual reproduction an egg and sperm unite and some traits come from each parent, so the offspring is never identical to either of its parents produced in meiosis Combining two individual’s genes creates variability in the population (an advantage in a changing environment)

Sexual Reproduction When a zygote is formed, it divides by mitosis creating 2, 4, and 8 celled stages and then forms a mass of cells called a morula Further mitosis creates a hollow ball of cells called a blastula (~1,000 cells) Subsequent divisions create tissue layers in the gastrula Gestation (the period of time it takes for an embryo to grow and change into an individual) can take no more than 3 weeks for a chicken but up to 2 years for an elephant Humans ~ 9 months

Sexual Reproduction Look at prepared slides of the following stages of starfish development: Egg 2-cell stage 4-cell stage 8-cell stage Morula Blastula Gastrula