1. Types of reproduction

2. Sexual
Requires two mates of opposite genders (male produces moving sex cell—sperm; female produces non-moving sex cell—egg)
Offspring are genetically different from parents and other offspring
Greater diversity increases the chance of survival for the group
However, there are usually fewer offspring and the cost of reproduction is higher for the female as she must create egg and/or provide for the offspring

3. Sexual (cont.)
Fertilization (the coming together of the egg and sperm) results in a zygote which develops into the offspring
External fertilization occurs outside the body of the female (frogs)
Internal fertilization occurs inside the body of the female (humans and many plants)
May involve pollinators such as birds and bees, wind or water
May involve intercourse when sperm is deposited inside the body of the female
Usually uses meiosis to create sex cells which have ½ the total chromosome number

4. Asexual
Does not require a mate (and therefore occurs more quickly and without the mating rituals)
Offspring are genetically identical to parent
Can generate large numbers of offspring in very little time
Isolation does not pose a problem to reproduction
However, changes in the environment may devastate the population
There are many forms

5. Binary Fission Used by very simple organisms
DNA is copied and cell splits
In eukaryotic cells this is basically mitosis to generate more organisms

6. Fragmentation (aka Vegetative Propogation)
Runners that lead to plantlet get broken “accidentally” and plantlet becomes a separate organism
Does NOT require regrowth
Best know in plants such as crab grass and strawberries

7. Regeneration Like fragmentation, original “accidentally” break off
However, BOTH parts must REGROW a portion to be whole again
Seen in starfish, planaria, many fungi

8. Budding
Intentionally grows a small version from the side and allows to fall off
Seen in yeast, sponges and cnidaria

9. Spore formation
Similar to budding but the bud is surrounded by a protective coat and only develops during non-ideal conditions
Spore is protected until desired conditions return
Often seen in ferns and fungi

10. Cloning
Generally used to describe a scientific procedure in which DNA from non sex cell is inserted into a sex cell which has had DNA removed intentionally
Does not occur in nature

11. Parthenogenesis
An unfertilized egg develops into an organism with ½ the normal DNA
Known to occur in frogs and snakes
Usually happens in a single sex environment