Unit 13: Reproduction Ch. 23, 24, 25

Why do organisms reproduce??? 2 main methods of reproduction…. What’s the difference??? How does sexual reproduction speed up evolution?

Examples of Asexual Reproduction 1. binary fission –DNA copied & organism divides in 2 examples of organisms that reproduce by binary fission… –bacteria –protists How is binary fission in protists different from in bacteria? –Why? Describe the offspring in relation to the parent.

2. budding –offspring begins to develop on the parent’s body & then breaks off examples of organisms that reproduce by budding… –yeast –Hydra Examples of Asexual Reproduction Describe the offspring in relation to the parent.

3. vegetative propagation –budding… in plants examples of organisms that reproduce by budding… –strawberries –potatoes Examples of Asexual Reproduction tuber runners (creepers)

creeper

4. fragmentation –fragment (piece) grows into new organism examples of organisms that reproduce by fragmentation... –sponges –sea stars 1 leg  new organism Examples of Asexual Reproduction

5. regeneration –regrowth of missing body parts examples of organisms that reproduce by regeneration... –Planaria –sea stars leg cut off  grows new leg –salamander What process allows regeneration to occur? –mitosis Examples of Asexual Reproduction

6. spores –contain DNA, cytoplasm & tough outer wall (coat) examples of organisms that reproduce by spores... –mushrooms –mold –mosses –ferns Examples of Asexual Reproduction fern sori What do you think the coat does? Why might some organisms produce a large number of spores?

Examples of Asexual Reproduction 7. parthenogenesis –unfertilized egg develops into adult (drone) examples of organisms that reproduce by parthenogenesis –Daphnia –aphids –honey bees

plants –undergo alternation of generations switch between a diploid (2n) sporophyte generation & a haploid (n) gametophyte generation We’re just going to focus on the sporophyte generation… flowers…. Sexual Reproduction in Plants

The flower is the plant’s reproductive organ. Sexual Reproduction in Flowering Plants (pistil)

flower is reproductive organ (pistil)

female parts –carpel (pistil) stigma  sticky tip to trap pollen style  long & narrow –sperm travels through ovary  swollen base that contains the ovules where eggs are produced Sexual Reproduction in Flowering Plants

male parts –stamen anther  produces pollen that contains sperm filament  “stalk” that supports anther Sexual Reproduction in Flowering Plants

Stamens & Carpels

parts that are neither female nor male –sepals  protect young flower bud leaf-like structures at flower’s base –usually green, but can be same color as petals –petals  attract pollinators located in/above the sepals –can be large & colorful –can be scented –can produce nectar Sexual Reproduction in Flowering Plants

Let’s see if you got that… What are 3 & 4 together called? What are 5, 6, & 7 together called? Sexual Reproduction in Flowering Plants

Most flowers have both male & female parts. –can self-pollinate or cross-pollinate Some flowers are only male or female. –must cross- pollinate… »Why is this beneficial? Sexual Reproduction in Flowering Plants What is pollination? transfer of pollen from an anther to a stigma

Pollen composed of 3 nuclei –1 tube nucleus –2 sperm nuclei Ovule has 3 nuclei –2 polar nuclei (becomes food/endosperm) –1 egg (becomes embryo) Sexual Reproduction in Flowering Plants

double fertilization –1 sperm nucleus + egg = zygote (embryo) –1 sperm nucleus + 2 polar nuclei = endosperm (food) Sexual Reproduction in Flowering Plants

1. Pollen from anther lands on the stigma. Tube nucleus moves through style forming a pollen tube to the ovule. 2. Two sperm nuclei travel through the pollen tube made in the style to ovule. 3. In ovule: One sperm nucleus fertilizes the egg to form a zygote that develops into the embryo. One sperm nucleus fertilizes 2 polar nuclei to form endosperm/food for the embryo. Path of pollen to egg

after fertilization: –ovule matures into seed seed contains embryo & food –ripened ovary becomes the fruit Seed coat embryo Sexual Reproduction in Flowering Plants

animals –no alternation of generations –gametes produced in ovaries & testes –can have external fertilization (spawning) or internal fertilization –can have external development or internal development Sexual Reproduction in Animals

external fertilization –Where does it occur? aquatic environment, not in mother –Why in water? »b/c needs water for sperm to swim to egg –Number of gametes? large #s released –Why? »chances of fertilization & survival low, but increased by synchronized release of gametes (ensured by mating behaviors) Sexual Reproduction in Animals Do animals that use external fertilization exhibit parental care?

internal fertilization –How is it different from external fertilization? happens inside mother –How is it an adaptation to life on land? moist, protective environment –Number of gametes? male  many, female  few –Why is it better than external fertilization? chances of fertilization & survival are higher b/c sperm only exposed for short time Sexual Reproduction in Animals

humans Sexual Reproduction in Animals

*Accessory glands seminal vesicle, prostate, bulbourethral (Cowper’s) gland penis Male Reproductive System Anatomy—Side View

1. Sperm cells are produced by the testes in the seminiferous tubules. 2. Sperm are stored in the epididymis. 3. Sperm pass through the vas deferens. 4. Accessory glands along the vas deferens add seminal fluids (water, buffers, & nutrients) to sperm. –combo of sperm & fluid is called semen. 5. Semen passes through the urethra before leaving the penis during ejaculation. Male Reproductive System Anatomy: The Path of Sperm from Production to Ejaculation

Let’s Review

Male Reproductive System Anatomy— Front View

Let’s Review A B C F E D

Structure of Male Sperm

Female Reproductive System Anatomy— Side View (fallopian tube)

Path of Sperm until fertilization: 1.enters vagina 2.passes through cervix 3.enters uterus 4.travels into oviduct (fallopian tube) where fertilization normally occurs After fertilization: 1.fertilized egg (zygote) travels to uterus from oviduct (f.t.) 2.implants in lining of uterine wall (endometrium) Development of fetus: 1.normally occurs in uterus Female Reproductive System Anatomy: The Path That Sperm Follows Until Fertilization, Where Fertilization Occurs, & Where Development Occurs

Let’s Review Female Reproductive System Anatomy—Side View A B C D (oval object in back) E

(fallopian tube) Female Reproductive System Anatomy—Front View

Where does: fertilization take place? implantation take place? the fetus develop? What is the pathway that sperm follows prior to fertilization? Female Reproductive System Anatomy— Front View

Formation of Eggs Follicles in ovary form eggs. ovulation –the release of egg from follicle

controlled by hormones prepares uterus for possible pregnancy usually occurs monthly 4 phases (~28 days) 1.thickening of uterine lining 2.ovulation egg matures & is released 3.passage of egg into uterus (if not fertilized) ~day 14 4.loss of unfertilized egg & lining (menstruation) Human Menstrual Cycle

Fertilization The Miracle Begins What is the pathway that sperm follows prior to fertilization?

Fertilization & Development

(below) Embryo & Fetal Development Animation Developmental Timeline

Labor & Delivery The big day! –3 stages

Asexual vs. Sexual Reproduction AsexualSexual # of parents gametes produced? genetic variety? time needed to produce offspring rate of population growth Domains/Kingdoms 1 Fast No Short No All 2 Slow Yes Long Yes All

Asexual Reproduction Sexual Reproduction vs. 2 parents  increases genetic variation long generation times  small # of offspring & pop. grows slowly parents often care for offspring  low death rate survival of individuals “fit” for environment more difficult, slow long generation times  small # of offspring & pop. grows slowly requires a lot of energy to find mate & carryout parental care of offspring requires a lot of energy easy, fast short generation times  can produce large # of offspring & pop. grows quickly requires little energy well adapted individuals spread quickly offspring are genetically identical to parent  no variation no parental care of offspring  high death rate poorly adapted individuals die easily