Biological Diversity Topic 2 ppt.pptx

TOPIC 2 A CLOSER LOOK AT VARIATION AND SEXUAL AND ASEXUAL REPRODUCTION HERITABLE AND NON-HERITABLE TRAITS 12 min HERITABLE AND NON-HERITABLE TRAITS • Heritable characteristics are passed down from generation to generation. • Ex. eye colour, hair type, and skin colour • Non-Heritable characteri...

TOPIC 2 A CLOSER LOOK AT VARIATION AND SEXUAL AND ASEXUAL REPRODUCTION HERITABLE AND NON-HERITABLE TRAITS 12 min HERITABLE AND NON-HERITABLE TRAITS • Heritable characteristics are passed down from generation to generation. • Ex. eye colour, hair type, and skin colour • Non-Heritable characteristics are acquired by each individual • Ex. athleticism, artistic ability, having big muscles, ability to play the piano ENVIRONMENT CAN IMPACT TRAITS • Height and weight can be affected by diet and exercise • Skin pigmentation due to sun exposure • Plant growth – light exposure/not enough water/nutrients DISCRETE VS. CONTINUOUS VARIATION • Discrete variation are characteristics that only have a few defined forms such as either/or • Ex. Being able to roll your tongue or not; albino or not • Continuous variation are differences that have a range of forms • Ex. Height, weight, hair, eye colour HUMAN TRAITS LAB • You will be investigating the frequency of discrete traits by comparing physical characteristics inherited from your parents Discrete Characteristics Dominant and Recessive Traits 1.5 min REPRODUCTION The way a species reproduces determines how much variation the new individual will have. 1. Asexual reproduction involves only one parent • All offspring are identical to the parent because there is no change in DNA 2. 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. TYPES OF ASEXUAL REPRODUCTION There are 4 different • • • • Binary Fission Budding Spore Production Vegetative Reproduction • • • • Suckers Runners Cutting Tubers BINARY FISSION • What? A single celled organisms splits into two identical cells • Who? bacteria, amoeba, and algae BUDDING • What? The parent produces a bud or a smaller version. The bud will break off or remain attached as a self-sufficient individual *identical to the parent. • Who? Hydra, yeast, and coral SPORES • What? Spores are similar to seeds but there is only one set of DNA so there is no variation. One parent can produce many spores • Who? Fungi, green algae, molds, ferns VEGETATIVE REPRODUCTION Runners • Long stems that grow new plants along them ex. Strawberries, Spider Plants Suckers • Roots of plants that produce sprouts that create new plants ex. Cherry, and Apple Trees, Dandelions, Aspen Trees VEGETATIVE REPRODUCTION Tubers • Buds that produce new plants ex. Potatoes, Sweet Potatoes Cutting • Part of the parent plant is cut and roots can grow a new plant. Ex. Carnations, geraniums and chrysanthemums SEXUAL REPRODUCTION • Most animals and flowering plants reproduce sexually • Definition: Involves the exchange of genetic material between two individuals resulting in offspring that are genetically different from the parents SEXUAL REPRODUCTION IN ANIMALS The male gametes are called sperm cells and female gametes are called egg cells (ova). When these two gametes unite, it is called fertilization. This combination of the two gametes unite, it is called the zygote (first cell). 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 can develop inside the female (mammals) or outside (like an egg) Conception - Human 6 min TWINS • Scientists have long used twins to study the roles of nature and nurture in human genetics and how each affects disease, behavior, and conditions, such as obesity. • But a new study suggests a real application of finding the genetic and environmental roots of disease. Identical Twin s Space Twin s SEXUAL REPRODUCTION IN PLANTS • 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 Coniferous tree reproduction Flower Sexual Reproduction FLOWER DISSECTION LAB • The goal of this is activity is to better understand the parts of a flower and reproduction in flowering plants Label the Flower Watch Dissection Video 4 min SEXUAL REPRODUCTION IN PLANTS: How does it work? • • • • 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 SEXUAL REPRODUCTION IN PLANTS • Cross-pollination occurs when pollen from one flower is carried to the stigma of another flower of the same variety. • Cross-fertilization is the joining of these gametes that form a zygote. SEED DISPERSION • The embryo is produced inside a seed. Which protects and provides food for the embryo • The new embryo maybe dormant until it has suitable growing conditions • Seeds are dispersed away from each other and from the parent plant so that there is less competition between the parent plant and the new plants, and between the new plants. Most common methods of seed dispersion 1.Wind 2.Animal (internal or external) 3.Self Propelled 2.5 min REPRODUCTIVE STRATEGIES INVESTIGATION • Using the profiles of different organisms provided, compare how the three organisms reproduce (ensure you get at least one sexual and one asexual reproduction). Fill in the chart (2 sides) • If you need a different sheet let your teacher know ORGANISMS REPRODUCE ASEXUALLY AND SEXUALLY ●Some species can reproduce both sexually and asexually – Ex. Aphids ●During the growing season, females reproduce asexually producing more females (asexual) ●Over the summer these female young mature and will reproduce asexually ●In the fall, due to colder climates they will switch to sexual reproduction. Males and females mate and lay eggs for a new colony that hatches in the spring WHICH IS BETTER? IT DEPENDS! Asexual Reproduction • advantages • does not require special cells • no mate required • can produce offspring quickly • in a stable environment it creates a large population • disadvantages • limited ability to adapt • face massive die-off if environment changes Sexual Reproduction ●advantages ●lots of variation within a species ●able to live in a variety of environmental settings ●able to adapt to changes in the environment ●disadvantages ●needs time & energy ●produce small populations TIME TO REVIEW :D COMPLETE THE TOPIC 2 ASSIGNMENT TO SHOW WHAT YOU HAVE LEARNED! ANSWER IN FULL SENTENCES AND USE EXAMPLES