Reproduction

Lec tu r e on Repr oduc ti on Bio 1 SDJacinto Institute of Biology UP Diliman

Mo des of Re pro duction 

Asexual- process by which a single parent reproduces by itself. Many animals, especially invertebrates, can also reproduce asexually. Asexual reproduction produces offspring that are genetically identical to the parent.  Sexual reproduction -process by which two cells from different parents unite producing the first cell of a new organism.

www.tiscali.co.uk/.../ hutchinson/m0007021.html

www.sirinet.net/ ~jgjohnso/fungi.html

http://www.tulane.edu/~wiser/protozoology/notes/images/ciliate.gif

ASEXUAL VS. SEXUAL REPRODUCTION: SURVIVAL AND VARIATION  Most animals reproduce sexually by producing haploid gametes.  Sexual reproduction helps create and maintain genetic diversity in populations; helps improve species' abilities to cope with environmental change  Asexual reproduction allows animals to increase their numbers rapidly; provides no genetic diversity, a major environmental change could cause the extinction of the species

Photo courtesy David Parks Paradoxophyla palmata, a narrowheaded frog native to Madagascar. The frog's brown and yellow coloring, as well as its rough texture, allow it to blend in with the mud and tree trunks in its environment.

http://www.geocities.com/br isbane_loopers/images/wpe 109.jpg

http://lpmpjogja.diknas.go.id/kc/a/animal/animal-camouflage.htm

De tails about se xual reproduction  Gametogenesis- production of gametes (sperm and egg)  Haploid gametes produced  Genetic variation  Structural changes in gametogenic cells to fit into their roles

www.anselm.edu/.../ genbio/mitosisnot.html

Crossing over of homologous chromosomes causes genetic variations in offsprings

Portions crossed over

Preparations of female gamete (egg)  Reductional division and crossing over  Growth in size (for some this is considerable)  Coverings such as jelly (example in the frog egg) are made

www.emc.maricopa.edu/.../ BioBookANIMORGSYS.html

www.tarleton.edu/ ~anatomy/oogenesis.html

HUMAN OVUM

Pr epara tio ns o f th e male g ame te  Reductional division and crossing over  Development of head with hydrolytic enzymes (acrosome)  Development of propelling tail with mitochondria  Reduction in size (considerable )  Many organelles are discarded

www.uh.edu/~tgill2/ WebCTPicturesw.htm

www.sunydutchess.edu/ ahbs/Scala/Bio102/

tecn.rutgers.edu/ bio342/spermatogenesis.htm

FERTILIZATION

FERTILIZED EGG

Male and female pronuclei

CLEAVAGE

2-CELL EMBRYO

mil.citrus.cc.ca.us/.../ Chapter40notesLewis.htm

mil.citrus.cc.ca.us/.../ Chapter17notesLewis.htm

Clo ni ng -making an identical copy -organismal cloning by somatic cell nuclear transfer

Molecular cloning

DOLLY July 5, 1996- February 2003

www.stanford.edu/.../ cloning/timeline.html

Cloni ng of D ol ly invol ved… Starvation (reprogramming!) and subsequent

 Starvation (reprogramming!) and subsequent implantation of DNA from specialized, nonsexual cells of one organism (in the case of dolly, from the mammary gland cells specialized to make that organism's hair or milk) into an egg whose DNA nucleus has been removed.  The resulting egg and nucleus are shocked or chemically treated; egg begins to behave as though fertilization has occurred, resulting in the beginning of embryonic development of a new organism containing the entire genetic code of the first organism.

Cloning issues Dr. Glenn McGee U of Pennsylvania  a clone's DNA is exactly the same as that of the original organism.  Human cloning: the most controversial debate of the decade.  It's an answer to infertility, claim supporters.

Clo nin g i ssues  Failure, miscarriage, or deformed offspring likely in early experiments.  Some defects may not be revealed until a clone is mature.  Can the law prevent the birth of a clone when it's our right to have children?

.. An d more clo ning issu es

 Is a cloned embryo the same as a conceived embryo?  Does a clone have parents, autonomy, or even a soul?  Can cloned children choose their own destiny?  If humans "make" babies rather than "have" babies, are they playing God?

http://images.pharmaventures.com/review/cartoons/600/500/2006_01_cloning.jpg

On Feb. 27, 2003, the U.S. House of Representatives voted for the second time to ban all human cloning. Human Cloning Prohibition Act-prohibits people from knowingly attempting to perform human cloning or participating in such a procedure by shipping or receiving an embryo produced from human cloning, whether the cloned embryo is to be used for reproduction or research. A bill allowing cloning for research but ban it for reproduction failed (231-174 vote).

Th e Woo Su k Hw ang fraud  From National University of Seoul-faked production of human cloned embryo  Faked production of 11 patient tailored cell lines from embryonic clones

'The Journal of Regenerative Medicine', November 26, 2001 issue - published that the researchers of Advanced Cell Technologies, a legitimate research institute in Massachusets has successfully cloned a human embryo for research

Is there discrimination among human beings? Is right to life based on the measure of time of their development? (thus is an embryo worth less than a fetus, and a fetus less than a child, a child less than an adult?)

Baby

The Cloning of Hitler

Assist ed Re pro ductive Te chniques (A RT)

acfs2000.com/ html/learn/ivf.html

HUMAN FERTILIZATION

In vivo

In vitro Hormonal stimulation

Egg activation

Fertilization Embryo transfer www.oakbrookfertility.com/ files/ivf_et.html

www.gfmer.ch/.../ IVF_Fig2.html

 That’s all for this topic….

“Now Japanese scientists have written men out of the reproduction rulebook, and created fatherless mice.”

Helen Pearson, 2004. Mouse created without a father. Nature: Science Update