The continuity of life… REPRODUCTION The continuity of life…

What Is Reproduction? Reproduction is the process by which organisms produce more of their own kind…can be sexually or asexually Think about it…Without it…all life on earth would cease to exist

ASEXUAL VS SEXUAL Asexual REPRODUCTION SEXUAL REPRODUCTION ASEXUAL Characteristic Requires ONE parent. NO sex cells, NO fertilization Advantage/Disadvantage Do NOT have to find mate Offspring have NO variation Offspring are genetically identical to parent cell SEXUAL Characteristics Requires TWO parents Involves TWO sex cells Requires fertilization Advantages/Disadvantages Requires mate Offspring have variation Offspring are NOT genetically the same Offspring are combination of BOTH parents

Types of Asexual Reproduction Binary Fission… Budding… Spore production Regeneration Propagation Vegetative Artificial Parthenogenesis

1. Binary Fission… The nucleus divides by mitosis and the cytoplasm divides, forming 2 new daughter cells of equal size. Occurs in single celled organisms …bacteria, protists…amoeba, paramecium

2. Budding… The division of cytoplasm is unequal so one of the daughter cells is larger than the other. The daughter cells can separate or remain attached.

Budding… New Organisms Arise as an Outgrowth from the Parent Organism Seen Mostly in Marine Animals Examples Include; Sponges, Corals and Jellyfish… Also seen in yeast and Hydra Coral Polyp Photo courtesy Jeffrey N. Jeffords http://oceanworld.tamu.edu/students/coral/coral1.htm

3. Sporulation… Spores are produced in large numbers by mitosis. Spores are surrounded by a tough coat to help them survive harsh environmental conditions. Seen in mosses, fungi…mushrooms, molds

4. Regeneration… This refers to the ability of some animals to re-grow severed parts. Some of these animals can also grow new organisms from the severed pieces Segmented Worms and Sea Stars

5. Propagation VEGETATIVE New plants develop from the roots, stems, or leaves of the parent plant. Three Types Tubers Bulbs runners

Tubers Tubers are underground food stores which stores food over the winter and provides a new plant with food until it can make its own. Examples: potato, artichoke, yam, water chestnut, arrowroot Tuber info from http://www.foodsubs.com/Tubers.html Taro- Japanese potato Food made by the new plant is sent to make new tubers. Thereby reproducing itself.

Bulbs E.g. daffodils, lilies

Runners Runners are side shoots which grow out from the parent plant. Buds form at points along the runner and eventually these buds form roots and grow into new plants. Examples: spider plant (Anthericum), strawberry (Fragaria x ananassa)

Propagation Artificial With plants, but with human intervention Two main types Cuttings Grafting

Cutting They can be placed in moist soil or water (and sometimes Cuttings are small pieces of stem with some leaves attached, the new plant grows from this. SQA- Describe ways of propagating flowering plants artificially by cuttings and graftings Source counties.cce.cornell.edu/.../propagation.htm They can be placed in moist soil or water (and sometimes dipped in rooting powder).

Grafting A cut stem of one plant (with good flower or fruit growth) (the graft) is taken and firmly attached to the rootstock of another plant (which has a strong, established root system) (the stock). Examples- roses, fruit trees

6. Parthenogenesis… Offspring can arise from unfertilized eggs. Includes some Fish, Reptiles, Amphibians and Aphids. Most of these species can switch between Sexual and Asexual Reproduction. (depending on conditions) http://aolsearch.aol.com/aol/imageDetails?invocationType=imageResults&query=photos+of+parthenogenic+species&img http://www.duke.edu/%7Ejsr6/Hawaiipics/Rhampho.jpg http://spot.colorado.edu/~noyesr/TEACHING/4800%20Fall%202002.%20Biology%20and%20Evolution%20of%20Sex/Gynogenesis.Poecilia.pdf www.ag.ndsu.nodak.edu