Asexual and Sexual Reproduction Animal Development

1. Asexual and Sexual Reproduction&Animal Development

2. Sexual Reproduction There are ~1.5 million different types of living species known Some reproduce sexually, asexually, or both Sexual reproduction involves haploid gametes coming together and forming a diploid zygote (called fertilization)

3. Asexual Reproduction Spores are haploid reproductive cells that are capable of becoming an offspring without fusing with another cell—it does not involve fertilization This happens in some molds Budding is another form of asexual reproduction where a growth of a copy of the adult buds from the adult itself until the bud breaks off and becomes its own organism This happens in yeast Fission is another form used by some single-celled organisms such as bacteria or amoeba The organism divides by mitosis to make a new cell

4. Protists Protists are single-celled eukaryotic organisms Earlier this semester I classified Amoeba and Paramecium in with the prokaryotes, but this is really not true. Protozoans are named b/c they are “animal-like” and actually resemble eukaryotes in the way they work than prokaryotes like bacteria Ex: Paramecium can reproduce asexually by fission or sexually by conjugation Activity 1 on videoscope Paramecium (remember they move via cilia) Draw a Paramecium not dividing and also one dividing by fission on pg. 118

5. Fungi Fungi are eukaryotic organisms. They are also saprophytic (this means they get their food from dead organic matter) Fungi can be multicellular or unicellular (yeast) Some are parasitic (ringworm, athlete’s foot)

6. Fungi Rhizopus is a fungus that exhibits sexual and asexual reproduction It is made up of sections called hyphae Can be separated by walls (septate) or not separated (aseptate) The entire organism forms a mycelium (a mass of hyphae) Asexual reproduction involves the production of sporangia (spores are inside the sporangia) Activity 2 – Look at prepared slides and draw and label the hyphae, mycelium, and sporangium on pg. 118

7. Fungi Yeast Yeast are unicellular fungi that reproduce by budding Budding occurs rapidly under ideal conditions (mixed with sugar and water in warm temps) (remember the yeast fermentation lab) Activity 3 —Draw a yeast cell with a bud on pg. 119

8. Animal Reproduction & Development (Investigation 14) Asexual Reproduction – genetic material of one individual is passed onto the next Sexual Reproduction – genetic material of two individuals are combined Involves the joining of gametes produced in meiosis Combining two individual’s genes creates variability in the population (an advantage in a changing environment) Asexual Reproduction would only be efficient in a highly stable non-changing environment Hospitals and MRSA (methicillin resistant Staph aureus)

9. Reproduction in Hydra Hydra have a central body cavity (Phylum Cnidaria; same as jellyfish—radial symmetry) Also have tentacles that surround the mouth and which are equipped with nematocysts (stinging cells) They reproduce asexually by budding (same as yeast) Activity 1– Draw a picture of a budding Hydra on pg. 184

10. Reproduction in Hydra Hydra also reproduce sexually Sexual reproduction involves ovaries and testes which develop in the outer layer of cells Some Hydra have both ovaries and testes, but most do not Testes are small outgrowths found toward the mouth and contain many sperm Ovaries are large and round Activity 1 cont’d—Draw a sketch of Hydra containing ovaries and testes

11. Human Reproductive System Human male reproductive system functions to deliver a haploid gamete (sperm produced by meiosis) to an egg (also haploid) Sperm: Are produced in the seminiferous tubules (which are tightly coiled forming the testis) Are stored in the epididymis Pass through the vas deferens to the prostate gland and through the urethra of the penis The walls of seminiferous tubules are composed of cells that undergo meiosis to make sperm Activity 2 – look at prepared slides of testis and sperm and draw on pg. 185 & 186

12. Human Reproductive System Female reproductive system functions to produce a haploid gamete (egg) and allow for fertilization producing a diploid zygote and implantation in the uterine wall Egg: Is produced inside the ovary Travels down the oviduct (AKA Fallopian tube) Implants into the uterine wall Single large egg called ovum surrounded by many small follicle cells (produce estrogen and progesterone) When an egg is fully mature, it will rupture through the wall of the ovary and pass into the oviduct (ovulation) where it is ready to be fertilized Activity 2 – look at prepared slide of ovary and draw a mature follicle containing the ovum and follicle cells surrounding it on pg. 186

13. Animal Development When a zygote is formed, it divides by mitosis creating 2, 4, and 8 celled stages and then forms a mass of cells called a morula Further mitosis creates a hollow ball of cells called a blastula (~1,000 cells) Subsequent divisions create tissue layers in the gastrula Gestation (the period of time it takes for an embryo to grow and change into an individual) can take no more than 3 weeks for a chicken but up to 2 years for an elephant Humans ~ 9 months

14. Animal Development Look at prepared slides of the following stages of starfish development: Egg (oocyte) 2-cell stage 4-cell stage 8-cell stage Morula Blastula Gastrula Draw these on pg. 191-192

15. Sexually Transmitted Diseases The spread of STDs is something most people ignore and don’t think about Used to be mainly bacterial infections (syphilis or gonnorhea) which are curable But now viral infections such as AIDS and herpes top the list (Incurable) We will do an experiment to see how easily STDs can spread

16. Who’s Dirty? There are cups of water and pipettes for everyone in class ONE person in this class has an STD (glucose in their water) Everyone is to go around and sleep with only four people Take ½ pipette full of your water and your partner takes ½ of a pipette of theirs and you exchange “fluids” into one another’s cup MAKE SURE TO WITHDRAW YOUR ½ PIPETTE OF WATER BEFORE YOUR PARTNER EMPTIES THEIRS INTO YOURS Keep track of everyone you’ve slept with (name and #) in order After sleeping around with four people, have a seat and check to see if you’re dirty

17. Homework Homework grade today is your attendance Have a great weekend!