What is the process by which wild species have been turned into species with traits that are useful for human needs quizlet?
English naturalist Charles Darwin developed the idea of natural selection after a five-year voyage to study plants, animals, and fossils in South America and on islands in the Pacific. In 1859, he brought the idea of natural selection to the attention of the world in his best-selling book, On the Origin of Species. Show Natural selection is the process through which populations of living organisms adapt and change. Individuals in a population are naturally variable, meaning that they are all different in some ways. This variation means that some individuals have traits better suited to the environment than others. Individuals with adaptive traits—traits that give them some advantage—are more likely to survive and reproduce. These individuals then pass the adaptive traits on to their offspring. Over time, these advantageous traits become more common in the population. Through this process of natural selection, favorable traits are transmitted through generations. Natural selection can lead to speciation, where one species gives rise to a new and distinctly different species. It is one of the processes that drives evolution and helps to explain the diversity of life on Earth. Darwin chose the name natural selection to contrast with “artificial selection,” or selective breeding that is controlled by humans. He pointed to the pastime of pigeon breeding, a popular hobby in his day, as an example of artificial selection. By choosing which pigeons mated with others, hobbyists created distinct pigeon breeds, with fancy feathers or acrobatic flight, that were different from wild pigeons. Darwin and other scientists of his day argued that a process much like artificial selection happened in nature, without any human intervention. He argued that natural selection explained how a wide variety of life forms developed over time from a single common ancestor. Darwin did not know that genes existed, but he could see that many traits are heritable—passed from parents to offspring. Mutations are changes in the structure of the molecules that make up genes, called DNA. The mutation of genes is an important source of genetic variation within a population. Mutations can be random (for example, when replicating cells make an error while copying DNA), or happen as a result of exposure to something in the environment, like harmful chemicals or radiation. Mutations can be harmful, neutral, or sometimes helpful, resulting in a new, advantageous trait. When mutations occur in germ cells (eggs and sperm), they can be passed on to offspring. If the environment changes rapidly, some species may not be able to adapt fast enough through natural selection. Through studying the fossil record, we know that many of the organisms that once lived on Earth are now extinct. Dinosaurs are one example. An invasive species, a disease organism, a catastrophic environmental change, or a highly successful predator can all contribute to the extinction of species. Today, human actions such as overhunting and the destruction of habitats are the main cause of extinctions. Extinctions seem to be occurring at a much faster rate today than they did in the past, as shown in the fossil record. If you're seeing this message, it means we're having trouble loading external resources on our website. If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked. Agriculture The deliberate planting and harvesting of plants, and herding animals. Originated about 10,000 years ago when man shifted from a hunting-gathering lifestyle to growing food in permanent settlements At that stage, many wild plants would have been judged for their suitability to human needs. Domesticated Brought under cultivation as crop plants, through centuries of human selection Plant Breeding A branch of agriculture that focuses on manipulating plant heredity to develop new and improved plant genotypes for use by human society Art and a science Also called "accelerated" and "targeted evolution" that involves the application of genetic principles to crop improvement. Evolution
by artificial selection Agriculture in the 21st century faces - It has to produce more food and fiber to feed a growing population with a smaller rural labor force - More feedstocks for a potentially huge bioenergy market - Contribute to overall development in the many agriculture-dependent developing countries - Adopt more efficient and sustainable production methods - Adapt to climate change Agricultural food production: Each year humans re-create the food supply that feeds 7.7 billion people Reserves of staple foods would feed the world for less than 2 months Nearly 800 million people go to bed hungry every night. That's about 1 in 9 people on earth Malnutrition Caused by a lack of vitamins and minerals in the diet Commonly known as "hidden hunger" Affects the health of more than 2 billion people around the world, especially in poorer nations As an example, vitamin A deficiency affects 800 million people worldwide Projections: Feeding a world population of 9.1 billion
people in 2050 would require raising overall food production by some 70% between 2005/07 and 2050. We need to make as much progress in production efficiency in The success of plant breeding The introduction of science and technology into agriculture over the past two centuries has markedly increased agricultural productivity and decreased its labor-intensiveness. Chemical fertilization, mechanization, plant breeding and molecular genetic modification (GM) have contributed to unparalleled productivity increases. "Green revolution" crop varieties have increased yields 2 to 3 folds in many developing countries Increases in yield are derived both from improved varieties and from improved management. In vegetable crops, research suggests about a 50-50 split between genetic gain and gain attributed to management. Potential crisis in Plant Breeding Future increases are far from assured because of: - Under-investment in agricultural research Public sector research into classical crop breeding
is declining dramatically The goals of plant breeding - Yield The concept of genetic manipulation of plant traits The work of Gregor Mendel + Further advances in science to follow his discoveries = Plant traits are controlled by hereditary factors or genes that consist of DNA These genes are expressed in an environment to produce a trait. In order to change a trait or its expression, the breeder has to change the genes or modify the environment in which it is expressed. Changing the environment essentially involves modifying
the growing or production conditions. This may be achieved through an agronomic approach; for example, the application of production inputs (e.g., fertilizers, irrigation). Therefore, plant breeders seek to modify plants with respect to the expression of certain selected traits by modifying the genotype in a desired way by targeting specific genes. Two general types of plant breeding approaches - Conventional Conventional approach (traditional/classic breeding) Crossing two plants (hybridization) Is the primary technique for creating variability in flowering species. Remains the workhorse of the plant breeding industry. It is readily accessible to the average breeder and is relatively easy to conduct compared to the unconventional approach. Unconventional approach Using cutting-edge technologies for creating new variability that is often impossible to achieve with conventional methods. Requires special technical skills and knowledge. Expensive to conduct. The advent of recombinant DNA technology gave breeders a new set of powerful tools for genetic analysis and manipulation. Basic steps in plant breeding Regardless of the approach, a breeder follows certain general steps in conducting a breeding project A comprehensive plan for a
breeding project addresses: Objectives The breeder must define clear objectives for initiating the breeding program. In selecting breeding objectives, breeders need to consider: Germplasm Once the objectives have been determined, the breeder then assembles the germplasm (a pool of genetically variable plants) to be used to initiate the breeding program. The base plant population used to initiate a breeding program must include the gene(s) of interest. Selection After creating variability, the next task is to discriminate among the variability to identify and select individuals with desirable genotype. The selected plants are used to develop Evaluation The product reaches the consumer only after it has been evaluated. The potential cultivars are evaluated in the field, sometimes at different locations and over several years, to Certification and release of cultivar Before a cultivar is released, it is processed through a series Breeder's eye A good breeder should have a keen sense of observation. Several outstanding discoveries were made just because the scientists who were responsible for these events were observant enough to spot unique and unexpected events. - Luther Burbank selected one of the most successful cultivars of potato, the "Burbank potato", from a pool of variability. The Russet Burbank potato is produced on about 50% of all lands devoted to potato production in North America. Genetics in relation to Plant Breeding Genetics is the principle scientific basis of modern plant breeding. Plant breeding is about targeted genetic modification of plants. The science of genetics enables plant breeders to predict, to varying degrees, the outcome of genetic manipulation of plants. Genetic variation that is prerequisite for effective selection can be artificially created through principles of inheritance. Botany in relation to Plant Breeding Plant breeders need to understand the reproductive biology of their plants as well as their taxonomy. The taxonomy of plants helps to determine the wild relatives of a crop from where useful characters can be easily acquired through breeding. To design the most effective crossing program, plant breeders need to know if the plants to be hybridized are cross-compatible, as well as to know all details about flowering habits. Plant Physiology in relation to Plant Breeding Plants respond to environmental factors These factors are sources of physiological stress when they occur at unfavorable levels. Plant breeders need to understand these relationships in order to develop cultivars that can resist them for enhanced productivity Agronomy in relation to Plant Breeding Plant breeders conduct their experiments in both controlled (greenhouse) and field environments. An understanding of agronomy (the art and science of producing crops and managing soils) will help the breeder to provide the appropriate conditions for optimal plant growth and development that are needed for successful hybridization and selection in the field. An improved cultivar is only as good as its cultural environment. - - Without the proper nurturing, the genetic potential of an improved cultivar would not be realized. Plant Pathology and Entomology in relation to Plant Breeding Plant breeding for disease and pest resistance is a major objective in plant breeding programs. To be successful in these experiments, plant breeders need to understand the biology of the pathogen or insect pest against which resistance is being sought. This reaction of plants to pathogens (or pests) is controlled by Statistics in relation to Plant Breeding Plant breeders need to understand the principles of research design and analysis. Plant breeders must know basic statistical concepts for proper collection, analysis and interpretation of data. Statistics
is needed to analyze the variance within a population to separate real genetic effects from environmental effects. Bioinformatics in relation to Plant Breeding Bioinformatics is an interdisciplinary field that develops methods and software tools for understanding biological data. As an interdisciplinary field of science, bioinformatics combines computer science, statistics, mathematics, and engineering to analyze and interpret biological data. Common uses of bioinformatics include DNA sequence analysis and identification of candidate genes (e.g. disease-resistant genes) to be used in breeding programs. Biochemistry in relation to Plant Breeding Plant breeding is entering an era
of 'molecular breeding' where Plant breeders need to be familiar with the procedures of plant genetic manipulation at the molecular level, including the development and use of molecular markers and gene transfer techniques. Achievements of modern plant breeders All achievements of plant breeders can be grouped into several major areas: Yield increase Yields of major crops (e.g., corn, rice, sorghum, wheat, and For example, the yield of corn rose from about 2000 kg/ha in the In England, it took only 40 years to for wheat yields to rise from 2 metric tons/ha to 6 metric tons/ha. These yield increases are not totally due to the genetic potential of the new crop cultivars (about 50% is attributed to plant breeding) but are also due to improved agronomic practices (e.g., application of fertilizer, irrigation). Enhancement of compositional traits Breeding for a specific combination of traits to enhance nutritional quality or meet an industrial need are among the most important goals of plant breeding. For example, different kind of wheat are needed for different kinds of products (e.g., pasta, bread, cookies). Breeders have identified the quality traits associated with these uses and have produced cultivars with enhanced expression of these traits. Genetic engineering technology has been used to produce high oleic sunflower for industrial use. It is also being used to enhance the nutritional value of crops (for example, "Golden rice" with increased pro-vitamin A content). Crop adaptation Because many crops are cultivated in regions to which they are not native, plant breeders have developed cultivars with modified physiology to cope with such unfavorable conditions. For example, the duration of the growing period varies from one region to another. Another example, soils under arid conditions tend to accumulate large amounts of salts; therefore, salt-tolerant cultivars have been developed to be grown on such soils. The impact on the crop production system Crop productivity is a function of the genotype (genetic potential of the cultivar) and the cultural environment. The Green Revolution is an example of an outstanding outcome of the combination of plant breeding efforts and production technology to increase food productivity. An intensive production system with high input of fertilizers requires the availability of crop cultivars that are responsive to such high input growing conditions. Plant breeders have developed cultivars for such intensive agriculture. Another example, through the use of genetic engineering technology, breeders have reduced the need for pesticides in the production of major crops (e.g., corn, tobacco, soybean) with the Norman Ernest Borlaug - the father of the Green Revolution Dr. Borlaug was born in 1914. He earned his Ph.D. in Pathology and Genetics in 1942 from the University of Minnesota, and joined the Rockefeller Foundation team in Mexico in 1944, a move that would set him on course to accomplish one of the most notable accomplishments in history. The key technological strategies employed by Dr. Borlaug and his team were to develop high yielding varieties of wheat, and an appropriate agronomic package (fertilizer, irrigation, tillage, pest control) for optimizing the yield potential of the varieties. Wheat production in Mexico increased dramatically from its low 750 kg/ha to about 3200 kg/ha. The effort in wheat was so successful that the model was duplicated in rice in the Philippines in 1960. In 1970, Dr. Norman Borlaug was honored with the Nobel Peace Prize for contributing to curbing hunger in Asia and other parts of the world where his improved wheat varieties were introduced. The plant breeding industry Public sector vs private sector Public sector Private sector Duration and cost of plant breeding programs It takes about 7-12 years, or longer, to complete
a breeding program and release new cultivar for annual crops such as corn, wheat, and soybeans. The use of molecular techniques to facilitate the selection process may reduce the time for plant breeding in some cases. The use of tissue culture can reduce the length of breeding programs of perennial species. The development of new cultivars may cost from hundreds of thousands of dollars to even several million dollars. The cost of breeding also
depends on where and by whom the activity is being conducted The future of plant breeding in society For as long as the world population continues to increase, there will be a demand for more food. However, with an increasing population comes an increasing demand for land for residential, commercial, and recreational uses. Sometimes, farmlands are converted to other uses. Increased food production may be achieved by increasing production per unit area or bringing new lands into cultivation. Some of the ways in which society will affect and be affected by plant breeding in the future are: New roles of plant breeding The traditional roles of plant breeding (food, feed, fiber, and ornamentals) will continue to be important. However, new roles are gradually emerging for plants. The technology for using plants as bioreactors to produce pharmaceuticals will advance. The technology has been around for over a decade. Strategies are being perfected for the use of plants to generate pharmaceutical antibodies, engineering antibody-mediated pathogen resistance, and altering plant phenotype by immunomodulation. New tools for plant breeding New tools will be developed for plant breeders, especially in the areas of the application of biotechnology to plant breeding. New marker technologies continue to be developed and older ones advanced. Tools that will assist breeders to more effectively manipulate Genomics and bioinformatics will continue to be influential in the approach of researchers to crop improvement. Marker assisted selection (MAS) has become important in plant breeding in the 21st century. Training of plant breeders Plant breeding programs have experienced a slight decline in the number of graduates entering the field in the recent past. Because of the increasing role of biotechnology in plant genetic It has been observed that some commercial plant breeding companies prefer to hire graduates with training in molecular genetics, then provide them the needed plant breeding skills on the job. The key players in plant breeding industry The last decade saw a fierce race by multinational pharmaceutical corporations to acquire seed companies. There were several key mergers as well. The modern technologies of plant breeding are concentrated in the hands of a few of these giant companies. The trend of acquisition and mergers is likely to continue in the future. Publically-supported breeding efforts will decline in favor of for-profit programs. Yield gains of crops With the declining of arable land and the increasing policing of the environment by activists, there is an increasing need to produce more food or other crop products on the same piece of land in a more efficient and environmentally safer manner. High yield cultivars will continue to be developed, especially in crops that have received less attention from plant breeders. Breeding for adaptation to environmental stresses (e.g., drought, salt) will continue to be important and will enable more food to be produced on marginal lands. The biotechnology debate Modern technologies for plant genetic manipulation benefit the developing countries the most because they are in dire need of food, both in quantity and nutritional value. On the other hand, the intellectual property that covers those technologies is owned by the giant multinational corporations. Efforts will continue to be made to negotiate fair use of these technologies, and to help developing nations develop capacity for the exploitation of these modern technologies. Is Evolution a random process quizlet?Evolution is not a random process. The genetic variation on which natural selection acts may occur randomly, but natural selection itself is not random at all. The survival and reproductive success of an individual is directly related to the ways its inherited traits function in the context of its local environment.
What is evolution quizlet?Evolution. Evolution is change in the heritable traits of biological populations over successive generations. Adaptation. An adaptation, also called an adaptive trait, is a trait with a current functional role in the life of an organism that is maintained and evolved by means of natural selection.
Which process describes how dogs and crops were domesticated into their current forms?domestication, the process of hereditary reorganization of wild animals and plants into domestic and cultivated forms according to the interests of people. In its strictest sense, it refers to the initial stage of human mastery of wild animals and plants.
Is the study of where organisms live now and where they and their ancestors lived in the past?Biogeography - study of where organisms live, where they and ancestors lived.
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