Ch. 6.1 Introduction to Meiosis and Reproductive Systems

Chapter 6 pp. 188-190

Tell me what you already know about about the birds and the bees…

Sexual reproduction?

Eggs? Sperm?

The human reproductive systems?

Meiosis?

Chapter 5 ReviewAsexual Reproduction• Only 1 parent is required

• Offspring are genetically identical to the parent (clones)

Examples: binary fission, budding, etc.

Sexual Reproduction• 2 parents are required

• Offspring are genetically different from each other, from either parent, and from any other member of their species

Genetic diversity: Variation, or inherited genetic differences in a

species

• Sexual reproduction randomly sorts, or shuffles, DNA

leads to genetic diversity

• The combination of genes that an organism receives from its parents may allow it to better cope with changes in the environment

Genetic diversity gives some organisms a survival advantage over others

Q: How is genetic information passed along from parent to offspring?

A: In the chromosomes the offspring inherits from its parents.

Diploid number: two sets of chromosomes (2n)

Example: Diploid number in a human cell (2 x 23 chromosomes) = 46

chromosomes

2n

Haploid number: each set of inherited chromosomes; half the diploid number (n)

Example: Humans

1 set of chromosomes from female parent =

23 (n)

1 set of chromosomes from

male parent = 23 (n)

23

23

Sperm Egg

Gametes: specialized cells necessary for reproduction; produced by meiosis

male gametes = sperm cells

female gametes = egg cells

Fertilization: the process where an egg cell is penetrated by a sperm cell and the haploid genetic informationof both male and female gametes combines

Zygote:

the new diploid cell formed by the process of fertilization; receives half its chromosomes from its female parent and half its chromosomes from its male parent

Embryo: the stage of a multicellular organism that develops from a zygote

1 set of chromosomes from female parent =

23 (n)

1 set of chromosomes from

male parent = 23 (n)

2 sets of chromosomes, 1 from each parent =

46 (2n)

p. 190

Male and Female Reproductive SystemsGametes are produced in gonads (testes or

ovaries)

Male Reproductive System

Male Reproductive System

Testes: two glands located in the scrotum; produce sperm (spermatozoa) and testosterone (male hormone)

Scrotum: sac holding both testes

Epididymis: location of sperm maturation

Vas deferens: stores and transports sperm

Seminal vesicles and prostate gland: secrete fluid which mix with sperm to form semen

Male Reproductive System

Cowper’s Glands: secrete alkaline (basic) fluid into semen to help neutralize the acidity of the urethra

Urethra: a dual purpose tube that both semen and urine pass through to leave the body

Penis: the organ of transfer of sperm to female

Female Reproductive System

Female Reproductive System

Ovaries: produce eggs (ova) and secrete estrogen and progesterone

Oviducts (aka Fallopian Tubes): tubes which transport eggs to the uterus

Uterus: location of fetus development during pregnancy

Endometrium: lining of the uterus; site of implantation and development of the fertilized egg

Cervix: neck or opening from the uterus to the vagina

Female Reproductive System

Vagina: birth canal and receptacle for penis during sexual intercourse

Urethra: opening to the bladder

Clitoris: a small, pea-shaped bump at the front of the labia that contains erectile tissue (counterpart to male penis.)

Vulva: term which describes the external female sex organs

Labia: folds of tissues which cover the vaginal opening

Interesting Facts

• Eggs are formed inside the ovaries before birth (about 400,000); only about 400 will ever be released from the ovaries during ovulation

• A healthy man can produce between 10 million to 50 million sperm per day!

• The average swimming speed of a sperm is 8 inches per hour

• Sperm can only survive inside a woman for 2 to 7 days

Homework for next class:• Complete the Introduction to Meiosis and

Reproductive Systems worksheet

• Study for your Genetics and Reproductive Systems quiz

Works Citedhttp://thumbsterz.com/?p=534http://www.astraware.com/bzzz/http://www.lin-wood.org/161010115135732327/blank/browse.asp?A=383&BMDRN=2000&BCOB=0&C=56312http://blog.dialaphone.co.uk/2009/09/16/text-a-question-10-sites-that-answer-questions-via-text/http://hubpages.com/hub/Is-Sex-Necessary-for-Reproductionhttp://missevanson.blogspot.com/http://thunder.biosci.umbc.edu/classes/biol414/spring2007/index.php?

title=Genetic_variation&redirect=nohttp://baisically.blogspot.com/http://www.shropshireivf.nhs.uk/about-fertility/reproductive-system.asphttp://topnews.net.nz/content/22039-sperm-dash-lead-new-male-

contraceptionhttp://theano5.blogspot.com/