The Continuity of Life

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Slide 1

 

Reproduction:

The Continuity of Life

Reproduction

Sexual

Reproduction

Asexual

Reproduction

Slide 2

 

Asexual Reproduction: Genetically Identical Offspring

Budding

Regeneration

Parthenogenesis

… Cloning???

Slide 3

 

Budding…

New Organisms Arise as an Outgrowth from the Parent Organism

Seen Mostly in Marine Animals

Examples Include; Sponges, Corals and Jellyfish…

Coral Polyp Photo courtesy Jeffrey N. Jeffords

http://oceanworld.tamu.edu/students/coral/coral1.htm

Slide 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)

Slide 5

 

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://www.duke.edu/%7Ejsr6/Hawaiipics/Rhampho.jpg

http://aolsearch.aol.com/aol/imageDetails?invocationType=imageResults&query=photos+of+parthenogenic+species&img

http://spot.colorado.edu/~noyesr/TEACHING/4800%20Fall%202002.%20Biology%20and%20Evolution%20of%20Sex/Gynogenesis.Poecilia.pdf

www.ag.ndsu.nodak.edu

Slide 6

 

WHY???

Why would these organisms prefer asexual reproduction in stable conditions and sexual reproduction in more uncertain or less favorable conditions?

Slide 7

 

Imagine…

Imagine that a particular organism within a species lacks a certain gene (or ability to express a certain gene) necessary to break down a specific type of food, yet others of the same species within the population are able to break down that food.

What happens if the uncertain or less favorable conditions lead to that being the primary food source?

Slide 8

 

Death…

The parent organism and all of their offspring produced through parthenogenesis would die!

But, with the genetic diversity that comes from sexual reproduction the possibility of the offspring surviving is enhanced.