Species and Reproduction

REVIEW: Diploid vs. Haploid

Diploid Cells Cells that have pairs of similar chromosomes. Body Cells: Skin, bone, brain etc. The Human Body: –Each cell has 46 chromosomes OR 23 pairs

Haploid Cells Haploid ~ Single Form Do not have pairs of chromosomes Sex Cells –Sperm and egg They have ½ the number of chromosomes –23 chromosomes (one from each of the 23 pairs)

Target 4: Define asexual reproduction

Asexual Reproduction One organism produces one or more new organisms that are identical to itself and that live independently of it. The offspring will have hereditary material uniform with the hereditary material of the parent organism. This means they will be genetically alike.

Types of Asexual Reproduction Budding Regeneration Fission (Binary fission) Parthenogenesis

Budding New organisms arise as an outgrowth from the parent organism Seen in plants and in marine animals –Examples Include; Sponges, Corals and Jellyfish… Coral Polyp Photo courtesy Jeffrey N. Jeffords

Hydra

Cacti

Regeneration The ability to restore lost or damaged tissues, organs or limbs. It is a common feature in invertebrates, like worms and starfish.

Starfish

Planaria

Binary Fission Becoming two by division of the complete organism. A type of cell division Occurs in prokaryotes Eukaryote examples: algae, yeasts, protozoans

sion_186.jpg Bacteria

Paramecium

Parthenogenesis – virgin birth Offspring can arise from unfertilized eggs. Includes some Fish, Reptiles, Amphibians Honeybees &Aphids. Most of these can switch between sexual and asexual reproduction. (depending on conditions) 6/Hawaiipics/Rhampho.jpg ?invocationType=imageResults&query=p hotos+of+parthenogenic+species&img G/4800%20Fall% %20Biology%20an d%20Evolution%20of%20Sex/Gynogenesis.Poecilia.pdf

What type of reproduction is this??? Explain… E. Coli 

What type of reproduction is this??? Explain…

Target 5: Define gametes and their role in sexual reproduction

BACK TO Meiosis! cell division GAMETES, HALF CHROMOSOMES,  Meiosis = The form of cell division by which GAMETES, with HALF the number of CHROMOSOMES, are produced. DIPLOID (2n) vs.HAPLOID (n) Which is the correct term when referring to the number of chromosomes found in your gametes???  MeiosisSEXUAL reproduction.  Meiosis is SEXUAL reproduction.  TWO divisionsMEIOSIS I MEIOSIS II  TWO divisions (MEIOSIS I and MEIOSIS II). 23

Meiosis sperm or egg  Sex cells divide to produce sperm or egg. Also known as your???? HALF  Gametes have HALF the # of chromosomes. What is that term again???  Male: SPERMATOGENESIS -sperm  Female: OOGENESIS - egg or ova 24 HAPLOID GAMETES

Spermatogenesis 2n=46 human sex cell diploid (2n) n=23 Meiosis I n=23 sperm haploid (n) Meiosis II 25

Oogenesis 2n=46 human sex cell diploid (2n) n=23 Meiosis I n=23 egg Haploid (1n) Meiosis II 26 Polar Bodies (die)

Question: 20 chromosomes (diploid) chromosomes  A cell containing 20 chromosomes (diploid) at the beginning of meiosis would, at its completion, produce cells containing how many chromosomes? 27

Answer:  10 chromosomes (haploid or 1n) 28

 Fertilization = sperm eggzygote  Fertilization = The fusion of a sperm and egg to form a zygote. FERTILIZED EGG  A zygote is a FERTILIZED EGG n=23 egg sperm n=23 2n=46 zygote 29 WHY HAPLOID?

Haploid + Haploid = Diploid