Reproduction

 

ASEXUAL REPRODUCTION

•          The process where a single organism gives rise to offspring with identical genetic information.

•          Most of the cells in your body reproduce asexually (mitosis!)

•          Five (5) types of asexual reproduction…

1.        Binary Fission – organism splits into two offspring. (Ex. Paramecium)

2.       Budding – Offspring begins as a small outgrowth from the parent.  (Ex. Hydra)

3.       Fragmentation – New organism formed from a part that broke off of the parent. (Ex. Starfish)

4.       Spore formation – Spores (housed within the parent) are released and develop into a mature organism. (Ex. Bread mould)

5.       Vegetative Reproduction – The parent grows runners (ex. horizontal roots) which will develop into offspring. (Ex. Quaking Aspen).

 

SEXUAL REPRODUCTION

•          Process where genetic information from two cells is combined to produce a new organism with a new combination of DNA.

•          In complex animals the two combining cells come from two different parents.

•          The new organism formed is genetically different from its parents and other offspring.

•          Organisms that reproduce sexually show a wide variety of differences in traits within a given species.

•          Three types of sexual reproduction….

1.        Conjugation – two cells come in contact with each other and exchange small pieces of their DNA. (Ex. Bacteria can reproduce by conjugation AND binary fission)

2.       Hermaphrodite – An organism that produces both sperm and eggs; they can reproduce with any other member of their species. (Ex. Flat worm)

3.       Separate Sexes – Most complex animals have separate sexes, male and female, which produce sperm and eggs, respectively.  The methods of fertilization used are either internal fertilization (Ex. snow shoe hares) or external fertilization (Ex. Anemones).

 

REPRODUCTION IN FLOWERING PLANTS

•          Many plants reproduce sexually.  Some have both male and female sex organs on the same flower; others have male and female sex organs on different flowers.

•          Male Sex Cell – Pollen – produced in anthers which are the tips of the stamen.

•          Female Sex Cell – Eggs – located in the ovary at the base of the pistil.