catalyst: how are sex cells (sperm + egg) different from body cells? reflection: meiosis
TRANSCRIPT
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
Catalyst: How are sex cells (sperm + egg) different from body cells?
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
Catalyst: How are sex cells (sperm + egg) different from body cells?
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
Catalyst: How are sex cells (sperm + egg) different from body cells?
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
Catalyst: How are sex cells (sperm + egg) different from body cells?
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
http://waynesword.palomar.edu/lmexer2a.htm
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
Catalyst: How are sex cells (sperm + egg) different from body cells?
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
http://waynesword.palomar.edu/lmexer2a.htm
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
http://waynesword.palomar.edu/lmexer2a.htm
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!!!
Catalyst: How are sex cells (sperm + egg) different from body cells?
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
Catalyst: How are sex cells (sperm + egg) different from body cells?
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