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Transcript
July 29, 2015 Topic 3 Passing It On In this topic you will... 1) Distinguish between sexual and asexual reproduction 2) Identify examples of asexual and sexual reproduction July 29, 2015 HOW ARE CHARACTERISTICS PASSED FROM ONE GENERATION TO THE NEXT? - characteristics are passed from parents to offspring - these traits are called inherited or heritable traits July 29, 2015 ASEXUAL REPRODUCTION - Only one parent supplies the information to the offspring. - Characteristics of the parent are the same as the offspring ADVANTAGES - No need to find a mate - Reproduction can occur rapidly DISADVANTAGES - If environment changes the organism cannot adapt July 29, 2015 TYPES OF ASEXUAL REPRODUCTION Your Turn... Read pages 26 to 30 in your textbook and complete the chart on the next page. For each type of asexual reproduction explain the process, the advantages and disadvantages and examples of organisms that reproduce that way. 1. binary fission 2. asexual spores 3. vegetative growth in plants eg meristem 4. budding July 29, 2015 Binary Fission Process - single celled organisms - cell duplicates its contents - cell divides Advantages - can happen quickly - only one parent required Disadvantages - no variation can occur Examples - bacteria, amoeba Binary Fission (1:03) July 29, 2015 Asexual spores Process - single celled structures called spores Advantages - can happen quickly - only one parent required Disadvantages - no variation can occur Examples - fungi and algae July 29, 2015 Vegetative Growth (asexual reproduction in plants) Process - meristem is an area of rapidly reproducing cells at tips or roots and stems - meristems cells can specialize to make roots stems and leaves of the plant Advantages - plants can reproduce from clippings - can happen quickly - only one parent required Disadvantages - no variation can occur Examples - plants July 29, 2015 Budding Process -cells near the base produce a new group of cells called a bud Advantages - can happen quickly - only one parent required Disadvantages - no variation can occur Examples - cacti, sponges and hydra July 29, 2015 Cloning Controversy What is Cloning? - cloning in biology is the process of producing populations of genetically- identical individuals 3:18 July 29, 2015 Who is Dolly the Sheep? - on July 5, 1996 dolly the first cloned sheep was born - first mammal cloned - she lived to the age of 6 - died on Feb. 14, 2003 of lung disease and severe arthritis July 29, 2015 Can people be cloned? - not yet many claims have been made but have not been verified Ethical Issues to be Considered 4 Corners Discussion... (Your group will answer the questions and share your thoughts.) 1. What are the advantages and disadvantages? 2. Should there be any controls on experiments? 3. Who should be allowed to perform human cloning and under what conditions? July 29, 2015 SEXUAL REPRODUCTION - two parents supply the genetic material - offspring is a combinations of characteristics of both parents 36 sec July 29, 2015 BEST OF BOTH WORLDS - many organisms can produce sexually and asexually. - some molds like Rhizopus (bread mold) produce spores (asexual) but also produce zygospores that are a combination of genetic material from two sources (sexual). July 29, 2015 BACTERIAL CONJUGATION - Primitive form of sexual reproduction - A connection forms between two cells and genetic material is exchanged. - A form of genetic recombination occurs but not reproduction because there is no increase in number. July 29, 2015 Sexual Reproduction in Plant - plants reproduce by producing seeds - angiosperms are flowering plants - gymnosperms produce seeds in cones July 29, 2015 Sexual Reproduction in Plants 2:40mins page 33 Label diagrams A. - style, stigma and ovary are female parts (PISTIL) - anthers are the male part which produce pollen grains B. - pollen grain lands on stigma and forms a tube to fertilize the egg C. - prior to fertilizations other cells form the cotyledon to nourish the embryo D. - in angiosperms fruit surrounds the developing seed - fruit develops from the wall of the ovary July 29, 2015 Sexual Reproduction in Animals - for sexual reproduction in animals to be successful specific requirements must be met. - both male and female gametes must arrive in the same place at the same time. - gametes are delicate and require a moist environment Sperm Egg July 29, 2015 - for organisms that live in a liquid environment fertilization occurs outside the female. - for organisms that live on land, fertilization occurs inside the female - internal fertilization protects the egg cells inside the body, where conditions are warm and moist (mammals) - zygotes require specific conditions to develop - after the zygote develops and divides many times it becomes an embryo and later becomes a fetus. July 29, 2015 Look at page 51, draw and label the stages of the human life cycle in Figure 1.47 in your notes And Fill in the chart in your notes using the information in your drawing. July 29, 2015 Your Turn... Topic 3 Review We will complete Topic 3 Review as a KAHOOT July 29, 2015