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?

Outcomes 4. identify the role of variation in species survival under changing environmental conditions  6. describe examples of variation of characteristics within a species 10. distinguish between, and identify examples of, natural and artificial selection and the technology involved

Outcomes identify the role of variation in species survival under changing environmental conditions  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 describe examples of variation of characteristics within a species investigate the movement of characteristics from parents to offspring, and identify examples of characteristics in offspring that are: the same as the characteristics of both parents the same as the characteristics of one parent intermediate between parent characteristics different from both parents distinguish those characteristics that are heritable from those that are not heritable, and identify characteristics for which heredity and environment may both play a role identify examples of dominant and recessive characteristics describe, in general terms, the relationship of chromosomes, genes and DNA; and interpret their role as repositories of genetic information  distinguish between cell division that leads to identical daughter cells, as in binary fission and mitosis, and cell division that leads to formation of sex cells, as in meiosis compare sexual and asexual reproduction, in terms of the advantages and disadvantages  distinguish between, and identify examples of, natural and artificial selection and the technology involved

VARIABILITY AND SURVIVAL Variability is important if the environment of a species changes. Environmental change can be from humans, adding a predator in, change in climate or the introduction of a new disease. Example: Peppered Moth

VARIABILITY AND RESISTANCE Variability is good for species to survive environmental changes but it can also be negative for humans when they want to eliminate something. Certain strains of bacteria have become resistant to antibiotics and if the trend continues antibiotics may no longer be effective. Can you think of other examples of variability being a negative or positive thing?

NATURAL SELECTION Natural selection occurs when the environment “selects” which individuals within a species will be able to survive long enough to reproduce. Read page 24 Where else do we see natural selection occur? Answer question 5 under extend your learning and understanding.

Outcomes Describe examples of variation Identify examples of both discrete and continuous variation

Class Exploration Working in groups, complete the table and test the following features of your group members Characteristic Option 1 Option 2 dimples dimples present   no dimples eye colour brown/green blue/grey earlobe detached attached hair colour brown/black blond/red second digit finger short long skin pigment freckles no freckles thumb bends back does not bend back tongue can roll cannot roll

Heritable and Non-Heritable Characteristics Heritable characteristics are passed down from generation to generation. These include: structural and distinguishing traits such as eye colour, hair type, skin colour and ear lobes. Non-Heritable characteristics are acquired by each individual separately and not necessarily passed on from generation to generation. These can include athleticism, artistic ability, having big muscles, dyed hair

Discrete vs. Continuous Variation Discrete variation are characteristics that only has a few choices, either/or Example: being able to roll your tongue or not; albino or not Continuous variation are differences that have a range of forms Example: height, weight, hair, eye colour

Variations and the Environment Some variations may be influenced by interactions with the environment. These variations are NOT inherited Example: Height and weight. How is this influenced by the environment? Example: Changes in pigmentation of skin colour throughout different seasons

Review What is a heritable trait? What is a non-heritable trait? What is continuous variation? What is discrete variation?

Post- It Question #5 pg 29 A scientist wants to study continuous variation in a mouse population. What mouse characteristics would she/he investigate?

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

I Can… Distinguish between asexual and sexual reproduction Describe organisms that show both sexual and asexual reproduction Describe the main type of sexual reproduction Describe the main types of asexual reproduction

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?

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!)

To do: Work through A3B with a partner