HOW THEY DO IT!

1
HOW THEY DO IT!
http//sofia.usgs.gov/projects/wadingbird_wcas/

• Purpose of reproduction
• Replace the parents with 2 or more of the species
• of babies depends on the ability of the species
  to make it to sexual maturity

http//www.dartmouth.edu/burkle/Laura20Burkle20
-20Research.html
http//www.jburroughs.org/science/resources/flower
/flowertitle.html
www.wetwebmedia.com/snailidfaq3.htm
www.saburchill.com/chapters/chap0037.html
2

• Types of Reproduction
• Asexual
• Does not mix up the genes
• Offspring are identical to the parent
• Susceptible to being wiped out
• anemone splitting (138) budding (247)

www.geol.umd.edu/.../eltsite/lectures/sex.html
http//www.unitedstreaming.com
3

• Sexual
• Provides for genetic variation
• Involves ½ the genes from 1 parent ½ the genes
  from the other
• Differences in nature
• Some fish change sexes
• Some creatures are hermaphrodites (have both sex
  organs) sea slug reproduction (149)
• Sometimes the gender of the offspring is
  determined by the environment
• crocodile eggs lt70 ? male
• gt70 ? female

www.csulb.edu/depts/endo/
http//www.sardi.sa.gov.au/pages/ento/pasture_crop
_pests/broad_snail.htmsectID214tempID1
4

• Gametes ? sex cells
• egg (ovum) sperm
• Each of these has ½ of the genetic material
• 2 ways to have sexual reproduction
• external fertilization
• needs water!

http//www.morning-earth.org/Graphic-E/Cycle-index
.html
research.unc.edu/endeavors/spr2005/sperm.php
http//www.bookrags.com/Ovum
5

• Clams, urchins, abalone millions of eggs
  sperm are released
• No parental care (p.c.)
• Slim chances of survival

Coral Reef Spawning 233
courses.uvi.edu/BIO/141/Urchin.htm
6

• Fish (generalizations there are exceptions!)
• Millions of sperm are deposited near hundreds of
  eggs
• No p.c.
• Better chances of survival

Link to stickleback mating
http//www.sf.adfg.state.ak.us/region1/salmon/chil
kat.cfm
7

• Frogs (generalizations there are exceptions!)
• Male mounts the females and releases sperm as the
  eggs are released.
• No or very little p.c.
• Better chances of survival

Link to video
www.dailycal.org/article.php?id16489
8

• Internal fertilization on land
• No water need a penis
• Egg is fertilized in the female
• Increased chance of survival
• Parent selection
• Reptiles (generalizations there are
  exceptions!)
• Lay eggs can go anywhere ? water is in the eggs
• Little p.c.
• Great chances of survival

http//www.worldbook.com/wb/Students?content_spotl
ight/reptiles/live_reproduction
9

• Birds (generalizations there are exceptions!)
• Lay eggs ? female sits with eggs
• Shell around the water bag
• Food (yolk) allows for longer development
• High p.c.
• Really great survival

depts.washington.edu/ubna/recreation.htm
www.speysideorganics.com/OrganicFarming.htm
10

• Mammals (generalizations there are exceptions!)
• Water bag inside mother
• Better protection
• Baby is with female _at_ all times
• Temp. regulation
• Better feeding
• Long p.c.
• Fewer offspring to provide for
• really great survival!

www.innovations-report.com/.../report-32662.html
http//www.britannica.com/ebc/art/print?id57413a
rticleTypeId0
www.dhss.mo.gov/Nutrition_Pregnancy/