catalyst: how are sex cells (sperm + egg) different from body cells? reflection: meiosis

Catalyst: How are sex cells (sperm + egg) different from body cells?

Reflection:

Meiosis

MEIOSIS11-4

Making gametes…

http://waynesword.palomar.edu/lmexer2a.htm

Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htmFamily http://babyhearing.org/Parenet2Parent/index.asp

Remember:CHARACTERISTICS OF LIVING THINGS ALL LIVING THINGS __________

REPRODUCE


Reflection:

Meiosis

Asexual Reproduction: Producing offspring by a single parent without combining genes from another individual. The offspring are clones of the parent.

ASEXUAL REPRODUCTIONBacteria reproduce using__________________________________

Budding & regeneration are used by plants and animals to reproduce asexually (mitosis)

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmito.html

http://fig.cox.miami.edu/~cmallery/150/mitosis/c7.13.2.hydra.jpg

Planaria animation: http://www.t3.rim.or.jp/~hylas/planaria/title.htm

BINARY FISSION

ADVANTAGES OF ASEXUAL REPRODUCTION

•Can make offspring faster

•More energy efficient, no sperm and egg cells

•Don’t need a partner

http://www.mrgrow.com/images/cutting.jpg

DISADVANTAGES OF ASEXUAL REPRODUCTION

ALL ALIKE

Species CAN’T change and adapt

One disease can wipe out whole population

http://www.mrgrow.com/images/cutting.jpg


Reflection:

MeiosisAsexual Reproduction: Producing offspring by a single parent without combining genes from another individual. The offspring are clones of the parent.

-No sperm and egg cells, only 1 parent, use mitosis, offspring are clones.

SEXUAL REPRODUCTION

Combines genetic material

from 2 parents (sperm & egg)

so offspring aregenetically __________ from parents

DIFFERENT

Family image from: http://babyhearing.org/Parenet2Parent/index.asp


Reflection:

MeiosisAsexual Reproduction: Producing offspring by a single parent without combining genes from another individual. The offspring are clones of the parent.-No sperm and egg cells, only 1 parent, use mitosis, offspring are clones.

Sexual Reproduction: Producing offspring by combining genes from 2 parents. Not identical to parents, lots of variation.

ADVANTAGES OF SEXUAL REPRODUCTION

• Allows for variation in population

• Individuals can be different

• Provides foundation for EVOLUTION

• Allow species adapt to changes intheir environment

http://naturalsciences.sdsu.edu/classes/lab8/spindex.html

DISADVANTAGES OF SEXUAL REPRODUCTION

• Need to find a suitable partner-takes energy to find/court a mate

• Genetic recombination can allow for harmful recessive traits to re-appear

• Less efficient• Females at a disadvantage

-energy cost of carrying and rearing young

http://naturalsciences.sdsu.edu/classes/lab8/spindex.html


Reflection:

MeiosisAsexual Reproduction: Producing offspring by a single parent without combining genes from another individual. The offspring are clones of the parent.-No sperm and egg cells, only 1 parent, use mitosis, offspring are clones. Sexual Reproduction: Producing offspring by combining genes from 2 parents. Not identical to parents, lots of variation.

-Sperm and egg cells, 2 parents, use meiosis to create sex cells, offspring are not identical to parents.

MEIOSIS is the way…

to make cells with ½ the number of chromosomesfor sexual reproduction


EGG + SPERM

If egg and sperm had same number of chromosomes as other body cells . . . baby would have too many chromosomes!

http://www.angelbabygifts.com/Image by Riedell Image by Riedell

http://www.acmecompany.com/stock_thumbnails/13217.forty-six_chromosomes.jpg

Click the image to play the video segment 11A.

Video 1

Meiosis Overview


Reflection:

MeiosisAsexual Reproduction: Producing offspring by a single parent without combining genes from another individual. The offspring are clones of the parent.-No sperm and egg cells, only 1 parent, use mitosis, offspring are clones. Sexual Reproduction: Producing offspring by combining genes from 2 parents. Not identical to parents, lots of variation. -Sperm and egg cells, 2 parents, use meiosis to create sex cells, offspring are not identical to parents.

Mitosis Meiosis

MITOSIS•Makes ___ cells genetically _________ to parent cell & to each other

•Makes __________•Used by organisms to: increase size of organism, repair injuries, replace worn out cells


2identical

2nSOMATIC (body)

MEIOSIS•Makes ____ cells

genetically different from parent cell & from each other

•Makes _____ cells•Makes ______________

•Used for ____________

4

haploid

Gametes (sperm & eggs)

sexual reproduction


Mom

23 chromosomes

Dad

23 chromosomes

You have 23 pairs of chromosomes223 possible different combinations of chromosomes

70 trillion different possible offspring!!! Mathematically, this means that a SINGLE MATING PAIR

of humans could produce MORE VARATIONS OF OFFSPRING THAN THE TOTAL NUMBER OF HUMANS

BEINGS THAT HAS EVER LIVED!!!


Reflection:

MeiosisAsexual Reproduction: Producing offspring by a single parent without combining genes from another individual. The offspring are clones of the parent.-No sperm and egg cells, only 1 parent, use mitosis, offspring are clones. Sexual Reproduction: Producing offspring by combining genes from 2 parents. Not identical to parents, lots of variation. -Sperm and egg cells, 2 parents, use meiosis to create sex cells, offspring are not identical to parents.

Mitosis Meiosis

Chromosomes 1-22 (autosomes) contain genes for proteins to produce almost everythingThe last chromosomes determine your sex


Reflection: what are the main differences of sexual and asexual reproduction create a case where it is an advantage to have one or the other?

Meiosis

catalyst: how are sex cells (sperm + egg) different from body cells? reflection: meiosis

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