Notes: Sexual and

Asexual Reproduction

Sexual Reproduction – process in which 2 parents contribute genes (via

sperm and egg) to form a new individual

The resulting individual will be a combination of the male and female parents. This combination of genes creates an entirely unique individual unlike any other.

Sexual Reproduction –Requires two sex cells – egg and sperm

The egg and sperm join to form an entirely new organism (called a zygote)

Different from the parent organismOffspring has half of the Mother’s DNA and half of

the Father’s DNA

Benefits of Sexual Reproduction

• Genetic differences help a species survive adverse conditions like disease and environmental changes. If individuals have variation, some of them may have a gene that helps them survive when others do not.

Downsides of Sexual Reproduction

• Sexual Reproduction requires two individuals: It takes valuable time and energy to find or compete for a mate

• Sexual reproduction takes a while – depending on the size of the organism it can take a long period of time for the offspring to grow enough to be born. Ex: for humans it takes 266 days to reach full term and elephants take 624 days. (This is called a gestation period)

Downsides of Sexual Reproduction

• Offspring of sexually reproducing organisms usually require time for care from the parents after birth as well. There is time needed between litters.

• Organisms that reproduce sexually usually have offspring that develop inside the mother. This limits the amount of offspring one can have at a time.

Asexual Reproduction – reproduction involving only one parent organism.

The offspring created through asexual reproduction have the exact same genetic material as the parent; the offspring is a CLONE of its parent.

Benefits of Asexual Reproduction

• There is no energy or time required to find a mate.

• The production of offspring is usually external so the parent can have LOTS of offspring in a very short amount of time.

• There is no parental care required; since the offspring are copies of the parent there is no “baby” stage

Downsides of Asexual Reproduction

• Offspring of asexually reproducing organisms are identical to their parents. All members of the species are identical to one another. If a disease or change in environment occurs, all individuals will be affected.

Types of Asexual Reproduction:

Binary fission - one single cell copies itself and splits in two, creating a new

individual.

**This is how BACTERIA

reproduce**

Binary Fission in Bacteria

Types of Asexual Reproduction:

Budding- an offspring grows out of the

body of the parent and then breaks off.

**The offspring organism is smaller than the parent.The buds grow into fully matured individuals which eventually break away from the parent organism.**

Hydra is an Animal that Reproduces through

Budding

Types of Asexual Reproduction:

Vegetative Reproduction- process by which

new plant "individuals" arise or are obtained without production of seeds or spores

***Examples are the runners of strawberries, the tubers of potatoes, and the bulbs of onions***.

Types of Asexual Reproduction:

Regeneration- if a piece of a parent is detached, it can grow and develop into a

completely new individual.

**This is how STARFISH

reproduce**