Chapter 1 Notes for Botany

Chapter 1 This course is a freshman course, that will introduce you to some of the main topics that are important in Botany. The course has no prerequisites, and assumes that you have had little, or no, previous experience of Biology. Botany is the study of plants. The main subject matter in this course is: A) Life : the characteristics of living things B) Biochemistry : the important biological chemicals, like proteins and sugars C) Cell structure : what plant cells contain D) Chemical reactions : respiration and photosynthesis E) Cell division : including meiosis F) Plant ancestors and relatives : bacteria, protists and fungi G) The plant kingdom : spore plants, seed plants H) The applications of botany: crops, plant breeding and ecology Why study Botany? Plants are the source of many important products such as: Food (including grass for animals) Cotton and other fabrics Paper Wood Coal and oil Antibiotics and other medicines Botany as a Science Sciences, such as Biology, Chemistry and Physics, use a series of steps, called the scientific method, to try to understand the world around us. Some of the main steps are: 1. Make an observation (for example: plants in one part of my yard grow faster). 2. Come up with a hypothesis : an idea that can be tested. (eg. part of the yard gets more sunlight) 3. Make a prediction : a logical consequence of a hypothesis. (if slow growing plants are given more sunlight they will grow faster) 4. Test the prediction by conducting an experiment. Experiments are often designed to disprove the hypothesis. It is easy to disprove a hypothesis, but virtually impossible to prove that a hypothesis is correct in all possible situations. The experimental group differs from the control group usually in one variable eg amount of sunlight. Experiments should be repeatable. Sample size : the larger the sample, the more accurate the results. It is better to do an experiment with 200 plants than with 2 plants. Theory : a scientific theory has been supported by many experiments eg atomic theory, the theory of evolution. The main areas of Botany Plant anatomy: the structure of plants Plant physiology: the function of parts of the plant Plant taxonomy: the classification of plants Plant ecology: the interactions of plants and other species Genetics: the study of inheritance Economic botany: the practical uses of plants and plant products. Biological Classification Organisms are classified (put into groups) using this system devised by the Swedish biologist Linnaeus, around 1750. The example below is the classification of corn: Kingdom Plant Phylum ( Phyla ) Magnoliophyta Class Monocots (Liliopsida) Order Commelinales Family Poaceae (grasses) Genus ( Genera ) Zea Species mays The scientific name is the Genus name followed by the species name eg Zea mays. Members of the same species can interbreed to produce fertile offspring. Members of the same genus are similar, but do not interbreed in the wild. Example: wild perennial maize (Zeaperennis ) is in the same genus as corn, but they do not interbreed.