Reproductive System in Animals By: Kaitlin, Kayleen & Stephanie

Function Continue the existence of a species Individuals can multiply selves Reproductive tissue usually is separate one to form a new organism Cells: sperm and egg join to produce offspring

How it works: Asexual Reproduction Independent sexual reproduction that doesn’t need union of male/female germ cells Uncommon, certain invertebrates can perform

Asexual Reproduction Continued Hermaphroditism: one organism has both reproductive systems to reproduce Sequential hermaphroditism: an organism changes sex during its life - produce offspring without mating Parthenogenesis: an unfertilized egg to develop and hatch (insects)

How it works: Sexual Reproduction Union of 2 sets of DNA which usually comes from different parents Gonads: organ producing reproductive cells, needed in process - Male = testes: produce sperm - Female = ovaries: make eggs Sperm need wet environment get to egg Must meet when gonads contain mature gametes

Porifera

Porifera Sexual: sponges usually cross-fertilize one another Eggs and sperm join to produce a free-swimming larva settles on surface (rocks) Asexual: gemules (internal buds) Small cuts of sponges reproduce into a full-bodied sponge

Cnidarians Asexual/Sexual Most Jellyfish - both reproductive systems Multible Stages Polyp Stage: larva settles to the bottom, attaching self to a hard surface transforming into a polyp

Cnidarians: Egg Stage and Poly Colony Stage Egg Stage: Fertilized eggs develop inside the female or in pouches on the oral arms Larva is a short stage - leave mouth or pouch as free-swimming larva. Poly Colony Stage: Polyp develops into a polyp colony kept together by feeding tubes

Cnidarians cont. Ephyra & Medusa stage Polyp colony reproduce asexually and bud off tiny free-swimming jellyfish (called Ephyra) Ephyra grow in size and become adult Medusa (form of jellyfish)

Platyhelminthes Flatworms = hermaphrodites Eggs of each animal become fertilized from sperm of partner Eggs are laid in cocoons Yolk supplies with nourishment Then…hatch

Roundworms Reproduce sexually Separate sexes Chitinized spicules move into genital pore of the female. Sperm crawl along the spicule into female worm

Annelids: Worms and Leeches http://www.kidport.com/RefLIB/Science/Animals/Images/Worms.JPG

Annelids Sexually - some external fertilization - some hermaphrodites (rarely fertilize selves) - two worms attach – exchange sperm and store in sacs until eggs ready to be fertilized - mucus ring forms and a cocoon is produced to hold embryos

Mollusks Sexually Male shed sperm into water Fertilization in body of female water flow brings in sperm from male

Arthropoda: Insecta Insecta: separate sexes Reproduction is usually sexual - some eggs can develop without fertilization by sperm

Arthropoda: Crustacea - Fertilization when eggs laid - egg sticks to the female’s swimmeret - carries eggs until developed/survive on own.

Arthropoda: Arachnida Arachnida: Sexual reproduction -Developing embryos protected until ready to be born by - egg case - cocoon - on female

Echinodermata Sexual reproduction Uses external fertilization Have separate sexes

Chordata: Fish Sexually Female lays eggs Male fertilizes with a spray of liquid of sperm cells Yolk feeds the fish in the egg

Chordata: Amphibians Reproduces sexually Eggs fertilized outside of the mother's body Father immediately comes by and fertilizes them

Chordata: Reptiles Reproduces sexually Female's eggs fertilized by the male internally Egg then laid

Chordata: Aves (Birds) Reproduce sexually Fertilization: male place sperm in the female Bird lays eggs: protective shell Male often help keep eggs warm until hatched

Chordata: Mammal Reproduce sexually Female fertilized internally by male

Interesting facts In internal fertilization: a female not willing to mate often will injure/kill an aggressive male In sea horses, the males become pregnant At five to six weeks of age male mice reach puberty Snails are hermaphrodites but still need to mate to produce fertile eggs

Reproductive system interactions Only system not necessary for an individual organism to live Doesn’t depend on any other system to work Endocrine system - hormones in the bloodstream - system that interacts with reproduction

Possible Test Questions What is the Purpose of the Reproductive System? Define and explain the two reproduction processes? True/False: Hermaphrodites always reproduce with self.

Answers What is the Purpose of the Reproductive System? Continue the existence of a species and for individuals to multiply selves Define and explain the two reproduction processes? Sexual: 2 sets of DNA, Sperm must meet egg to fertilize Asexual: Independent reproduction not needing union of male/female cells True/False: Hermaphrodites always reproduce with self. False: Sometimes mate with other animals (Annelids) though have both parts

If Egg were to be fertilized…. Beginnings of embryo. As it grow, consume yellow part: yoke