Biological Diversity - Reproduction Notes

Unit A Biological Diversity Section 2.0 – 2.2 Reproduction, Passing Characteristics from One Generation to the Next  Section 2.0 – 2.1 Let’s Take a Closer Look at Variation ✔ Certain species have certain characteristics (Alligator vs. Crocodile)...

Unit A Biological Diversity Section 2.0 – 2.2 Reproduction, Passing Characteristics from One Generation to the Next  Section 2.0 – 2.1 Let’s Take a Closer Look at Variation ✔ Certain species have certain characteristics (Alligator vs. Crocodile) ✔ The process of “REPRODUCTION” guarantees that characteristics favored by the animals environment will be passed down from generation to generation ♒ These animals are the largest REPTILES in the world ♒ Belong to the same family known as “CROCODILIANS” ♒ Like to live in a HABITAT which is swampy and warm “Everglades National Park” ♒ Can't see an alligator's teeth when it's mouth is closed; its lower teeth fit snugly into pits in the upper jaw. In contrast, a crocodile's lower teeth are always visible ♒ Alligators have a broad snout Alligators have a broad snout, while crocodiles have a thinner snout. ♒ Alligators tend to be grayish black Alligators tend to be grayish black in color, whereas crocodiles  Heritable and Non-Heritable Heritable Characteristics: passed on from generation to generation (Example: Eye Color) Non Heritable Characteristics: acquired, not passed on (Example: A Person Learning to Play the Piano) Discrete and Continuous Variation Discrete Variation: differences in characteristics, defined form (Example: You have blue eyes or you don’t) Continuous Variation: differences in characteristics that have a range of forms (Example: Height of an Adult Human)  Section 2.2 - Asexual and Sexual Reproduction - Reproduction produces new individuals, however the production of new individuals can be identical or very different from one another 1. Asexual Reproduction: ONE PARENT ✔ All the offspring are identical to the parent (inherit identical characteristics) 4 Types of Asexual Reproduction a) Binary Fission b) Budding c) Spore Production a) Binary Fission – cell splits into two identical individuals Examples: protists (amoebas/algae) b) Budding – parent produces a small bud, which will eventually detach and form a new individual identical to the parent c) Spore Production – produced by a division of cells by the parent and each spore can develop into a new individual Examples: fungi, green algae, and moulds d) Vegetative Reproduction – does not involve the formation of a seed - Take a cutting from a plant and when placed in water the cutting will grow roots and soon develop into a new plant - Other forms are runners, tubers (potatoes), and bulbs (tulips/daffodils) - Each new individual plant are genetically identical to the parent plant 2. Sexual Reproduction: involves TWO individuals ✔ The offspring will have a mixture of characteristics of both individuals ✔ Sexual reproduction does not always involve male and female parents (as in humans), but can have specialized gametes (reproductive cells that have only one role - to join with another gamete during reproduction) Sexual Reproduction in Animals - Involves specialized cells called GAMETES (sex cells) Male Gametes (SPERM CELLS) Female Gametes (EGG CELLS) “OVA” ⮚ Unity of the male and female gametes is know as  Egg cell (the large sphere) and sperm cell (with a tail) - When the male and female gamete join and fertilization occurs the cell that is created is known as a “ZYGOTE” - The zygote continuously divides in a process known as “CLEAVAGE” - This continuous division results in a multi cellular life called a “EMBRYO” - Multi-cellular organism form inside the female (in most mammals) or, outside (in an egg shell) in other animals  Sexual Reproduction in Plants Plant reproduction involves gametes as well, male gametes and female gametes joining, during fertilization, to produce a zygote and then an embryo Most plants produce both male and female gametes, while some produce one or the other only 1. Pollen contains the male gametes and is found on the stamen. 2. Ovules contain the female gametes and are found in the pistil. 3. Pollination occurs when pollen is transferred from the anther of the stamen to the stigma of the pistil. ✔ Cross-pollination occurs when pollen from one plant is carried to the stigma of another plant by wind, water or animals (bees or butterflies) ✔ Cross-fertilization occurs when a grain of the pollen forms a long tube which grows down the style into the ovary The gametes unite to produce a zygote, which then develops into an embryo  Advantages and Disadvantages of Asexual and Sexual Reproduction Variation usually helps a species survive when the environment changes. Asexual Reproduction Advantages Disadvantages Does not require any specialized The great disadvantage is cells to produce a new plant that when the environment Produce many individuals very changes, all of the quickly organisms will die, This is an advantage in places They do not have the ability where the environment doesn't change very much (bacteria). to adapt to the change. By building a large population of organisms very quickly the species is able to thrive.  Sexual Reproduction Advantages Disadvantages providing lots of variation The main disadvantage is within a species that this process takes a lot helping it to survive when the of energy. environment changes This means that they can only produce small populations. Organisms that Reproduce both Sexually and Asexually ▪ Sponges are organisms that can produce both sexually and asexually. ▪ Most plants that produce seeds can also reproduce asexually (cuttings, runners). ▪ Depending on the environmental conditions the amount of energy varies, enabling the plant organism to control its population.  HOMEWORK!!!!! 1. Check and Reflect pg. 36 Q’s 1-4, and 6 2. Assess Your Learning pg. 37 Q’s 1-8