Unit A – Biological Diversity How do species become varied? Do animals and plants reproduce the same ways? Are there other ways that a species can be varied?

Asexual and Sexual Reproduction Reproduction produces new individual species. The way a species reproduces determines how much variation the new individual will have.

Outcomes 5. distinguish between sexual and asexual reproduction, and identify and interpret examples of asexual and sexual reproduction in different species, by looking at examples found in the environment 11. compare sexual and asexual reproduction, in terms of the advantages and disadvantages 

Asexual Reproduction Asexual reproduction involves only one parent. It is literally without sex. All offspring are identical to the parent because there is no change in DNA. There are 4 different types that we will look at Binary Fission Budding Spore Production Vegetative Reproduction

1) Binary Fission What? The cell splits into two cells and each one is identical Who? Single-celled organisms such as bacteria, amoeba, and algae What is the benefit of this?

2) Budding What? A parent produces a bud or a small version of itself. The bud will break off or remain attached as a self-sufficient individual—identical to the parent. Who? Hydra, yeast, and coral What is the benefit of this?

3) Spore Production What? Spores are created similar to seeds but only have the DNA of one parent so there is no variation. One parent can produce many spores, each of which will grow into a new individual identical to the parent. Who? Fungi, green algae, molds, ferns What is the benefit of this?

4) Vegetative Reproduction What? It is the reproduction of a plant not involving a seed.. What is the benefit of this? Runners What? Long slender stems that grow above the surface Who? Strawberries, Spider Plants Cutting What? Roots grow from the base of the stem into the soil while the shoot continues to grow and produce leaves. Who? Carnations, geraniums and chrysanthemums

4) Vegetative Reproduction What? It is the reproduction of a plant not involving a seed.. What is the benefit of this? Tubers What? Buds that produce new plants Who? Potatoes, Sweet Potatoes Suckers What? Roots of plants that produce sprouts that create new plants Who? Cherries, Apples, Blackberries, Dandilions

Sexual Reproduction Sexual reproduction occurs when two individual’s gametes (reproductive cells) combine The offspring that are produced from this union will have a mix of characteristics (DNA) from the two parents. What is the benefit of sexual reproduction? Why are siblings not exactly the same?

Sexual Reproduction in Animals The male gametes are called sperm cells and the female gametes are called egg cells (ova) When these two gametes unite, it is called fertilization This combination of the two gametes is called a zygote. The zygote splits through a process called cleavage and more cells are made Continued cell division creates a multi-cellular life form called an embryo This embryo develops inside the female (in most mammals) or outside (like an egg) in others.

Sexual Reproduction in Plants Most plants produce both male and female gametes Pollen- is the male gamete of a plant Stamen- male part of the plant where the pollen is found Ovules- contain the female gametes of the plant Pistil- the female part of the plant where the ovules are found

Continued The gametes unite to produce a zygote The zygote develops into an embryo Most embryos in plants are in the form of a seed Unlike animal embryo’s, plant embryos can remain dormant for a long period of time

Continued Pollination occurs when the pollen is transferred from the anther of the stamen to the stigma of the pistil. Cross-pollination occurs when the pollen from one plant is carried to the stigma of another plant. Cross-fertilization occurs when a grain of the pollen forms a long tube which grows down the style into the ovary. How can this transfer occur?

Sexual Reproduction Sexual reproduction occurs when two individual’s gametes (reproductive cells) combine The offspring that are produced from this union will have a mix of characteristics (DNA) from the two parents. What is the benefit of sexual reproduction? Why are siblings not exactly the same?

Advantages and Disadvantages of Asexual Reproduction Doesn’t need specialized cells or a way of bringing gametes together. Can produce lots of individuals very quickly Main disadvantage is that when environments change, all of the organisms will die, because they are not able to adapt to change

Advantage and Disadvantages of Sexual Reproduction Provides lots of variation which helps survive environmental change Main disadvantage is that this process takes a lot of energy Some organisms can produce sexually and asexually. How can this be beneficial? Examples of organisms that can do both Strawberries – seeds and runners; Carnations seeds and cuttings, and apply trees – suckers and seeds (what is inside your apple?) Sponges (Yes, they are animals), Jellyfish and starfish (lose a leg, make a new creature!)