Crossing Over potx

[...]... Internet or your local library for new books and videos on the topic of evolution New genetic discoveries are often reported in newspapers and magazines such as African Geographical and local newspapers Crossing Over: The Basics of Evolution xiii xiv HSRC Workbook Understanding Genes & Inheritance Part 1 Contents Overview 3 1 The cell 4 The structure of a cell 5 2 Measuring very small structures... foundational concepts on which the theory of evolution was built An understanding of genetics provides us with a deeper understanding of the actual mechanisms involved in the process of evolution Crossing Over: The Basics of Evolution xi HSRC Workbook Table 2: Content topics in the Natural Sciences learning area statement and their relationship to evolution Thus, evolution underpins the Natural Sciences... frequency distribution bar graph l  Explain the uses of genetic control of development in tissue culture, cloning, plant and animal breeding l Describe the role of natural selection in evolution Crossing Over: The Basics of Evolution  1 The cell Learning Outcome 2: Constructing science knowledge Assessment Standards Recalling meaningful information when needed Applying knowledge to problems that... powerful enough to distinguish even one cell without a microscope Cells were first discovered in 1665 by a scientist called Robert Hooke He sliced a piece of cork into a thin sheet He then studied the thin sheet of cork using a homemade microscope (A microscope makes things look much larger than their usual size) Hooke discovered that cork was made up of tiny boxes He decided to call these boxes cells Figure... membrane The cell membrane is a layer that separates the cell from the cells around it, or from the water or air that surrounds the cell It is like a very thin skin surrounding the cell contents Crossing Over: The Basics of Evolution  Diffusion is the process whereby a substance moves from a region of high concentration to a region of lower concentration The cell membrane plays a very important role... cellular respiration, therefore we expect that both plant and animal cells will contain mitochondria Activity 3 Would you expect to find chloroplasts in the cells of a plant root? Explain your answer Crossing Over: The Basics of Evolution  The nucleus In Figure 2 you saw that the nucleus is the biggest structure in the cell When cells were first seen, the microscopes were powerful enough to enable scientists... m Three It is difficult for us to picture such tiny amounts, but try to imagine that one millimetre division on your ruler divided into one thousand segments Each segment would be one micrometre Crossing Over: The Basics of Evolution 9 Using scientific notation, we can say that one micrometre is 1 x 10 -3 mm Micrometres are also called microns If one micrometre was divided into one thousand equal... cells from the inside of a human’s mouth a Use the scale bar to work out the actual diameter of five cells b Work out the average diameter of the cells Figure 5 Human cheek cells with scale bar Crossing Over: The Basics of Evolution 11 2 Figure 6 shows some cells from the surface of a leaf a Use the scale bar to work out the actual length and width of five cells b  ork out the average length and... carries out cellular respiration Mitochondria manufactures proteins Chloroplast  stores water, small molecules and waste products Endoplasmic reticulum allows substances to enter and leave the cell Crossing Over: The Basics of Evolution 13 3 The cell cycle Learning Outcome 2: Constructing science knowledge Assessment Standards Recalling meaningful information when needed Applying knowledge to problems... part of cell division, a new cell membrane forms across the middle of the parent cell, dividing it into two daughter cells The organelles of the parent cell are shared between the two daughter cells Crossing Over: The Basics of Evolution Figure 9 The cell cycle The dark shaded area is called interphase 15 4 he chromosomes and cell T development This section contains some advanced knowledge and exercises . also the act that chromosomes perform in the event of meiosis. Crossing over is fundamental to change. Crossing Over was designed to cover the basic content necessary for teaching the key concepts. females 38 Meiosis 40 Fertilisation 42 Solutions to activities 44 1 2 Crossing Over: The Basics of Evolution 3 HSRC Workbook Overview Part 1 of this workbook explores the way every cell carries. 0747 Fax: +1 (312) 337 5985 email: frontdesk@ipgbook.com www.ipgbook.com HSRC Workbook Preface The Crossing Over Pilot Teacher Trainer Research Programme (a project of the Human Sciences Research Council)