Variation, Adaptation & Antibiotic Resistance

Variation

• Variation refers to the differences between individuals of the same species

Continuous Variation

• Continuous variation shows a range of phenotypes between two extremes
• Examples are body length and body mass

Discontinuous Variation

• Discontinuous variation results in a limited number of phenotypes with no intermediates
• Examples of discontinuous variation include ABO blood groups, seed shape in peas, and seed color in peas

Causes of Variation

• Discontinuous variation is usually caused by genes alone
• Continuous variation is caused by both genes and the environment

Mutation

• Mutation is a genetic change that forms new alleles

Sources of Genetic Variation

• Mutation
• Meiosis
• Random mating
• Random fertilization

Adaptation

• Adaptation describes the process, resulting from natural selection, by which populations become more suited to their environment over many generations

Antibiotic Resistance

• The development of strains of antibiotic-resistant bacteria serves as an example of natural selection

Natural Selection

• Natural selection involves genetic variation within populations, many offspring, struggle for survival, and a greater chance of reproduction by better-adapted individuals who pass on their alleles to the next generation

Selective Breeding

• Selective breeding involves selecting individuals with desirable features, crossing them to produce the next generation, and selecting offspring with the desired traits

Types of Variation

• Discontinuous variations, caused by genes alone, result in a limited number of distinct phenotypes without intermediate forms
• Continuous variations occur when a characteristic is determined by many pairs of alleles, leading to a gradual transition between two extremes, & are influenced by genes and the environment

Factors Affecting Continuous Variation

• Many pairs of alleles influence the continous variation
• The Environment can play a role

Examples of Continuous Variation

• Height in humans
• Intelligence
• Weight
• Fingerprints

Meiosis in Genetic Variation

• Halves of chromosomes go into each gamete during meiosis
• Each chromosome set carries alleles with specific characteristics, causing variation

Fertilization in Genetic Variation

• Fertilization leads to a random combination of alleles
• One sperm fuses with one ovum, leading to the production of certain characteristics

Mutation in Genetic Variation

• Mutations are sudden changes in genes, chromosomes, or both

Factors Causing Mutation

• Chemicals like mustard gas, tobacco, and food preservatives can alter DNA structure
• Radiation, such as X-rays and cosmic radiation, can cause breaks in DNA
• Mutagens are factors that cause mutations

Types of Mutations and Reasons

• Changes in one or more chromosomes
• Increase or decrease in the number of chromosomes
• A part of a chromosome gets broken and lost, like in Down syndrome
• Changes in an individual's gene, like in sickle cell anemia

Selection

• Selection involves choosing the best-adapted varieties to an environment, allowing them to grow and reproduce

Artificial Selection

• Humans choose and breed the best varieties of domestic animals and plants to improve their strain
• New varieties within a species can result
• It does not form new species in most cases

Natural Selection

• The best-adapted organisms to their environment tend to have an increased chance of survival

Antibiotic Resistance Development

• As a result of mutations in bacteria, new strains develop that are resistant to certain antibiotics
• Nonresistant bacteria die, and resistant bacteria live and reproduce; this is survival for the fittest

Antibiotic Use

• Completing the full course of antibiotics is recommended because bacteria may remain and develop resistance, leading to ineffective reuse

Limited use of antibiotics can be due to

• Resistance to certain types makes their use ineffective
• Side effects or because they cannot be used by children or only used for certain types of care diseases

Evolution

• Evolution is the change in adaptive features of a population over time because of selection

Variation

• Variation is when individuals within a species are slightly different from each other
• These differences may make some varieties survive better than others

Overproduction

• Most organisms produce more young than will survive to adulthood

Struggle for Existence and Survival for the Fittest

• Changes in the environment, such as climate or food supply
• Some varieties may survive better than others

Advantageous Characteristics

• The best-adapted variety can live longer and reproduce more, passing on these characteristics to their offspring

Gradual Change

• The best-adapted variety, which becomes the largest in number, begins to replace others

DNA and Related Organisms

• Organisms that share a more recent ancestor have base sequences in DNA which are more similar than those that share only a distant ancestor
• The Sequences of bases in DNA and of amino acids in proteins give a more accurate classification than using the other features

Artificial Selection in Plants

• Increase crop yield
• Develop plants resistant to pests
• Increase the rate of reproduction in plants
• Develop identical plants by cloning
• Develop plants that can grow with less fertilizer

Methods of Artificial Selection in Plants

• Cross-breeding strains with desirable characteristics
• Cross-pollination prevents self-pollination
• Select the produced seeds to produce new plants, choosing those with the characteristics and allow for self-pollination for several times until all the offspring all have the required characteristics

Genetic Modification

• Genetic modification is changing the genetic material of an organism by removing, changing, or inserting individual genes
• An Example is the production of human insulin

insulin Whys (When, How, Why, Sources)

• People with diabetes need insulin injections because they cannot produce insulin
• Insulin was obtained from animals before genetic engineering
• The Disadvantages of obtaining insulin from animals are ethical concerns and because it is not identical to human insulin

Vector

• A plasmid vector is used

Genetically engineered plasmid

• Plasmids are separated by centrifugation
• The same restriction endonuclease used to cut the plasmid forming complementary sticky ends
• Genetically engineered plasmids that have genes for coding for insulin
• Many bacteria take up the plasmids into their cells and produce insulin

Value of plasmids when modified

• Bacteria has plasmids that can be isolated, modified, and introduced into bacteria
• Rapid reproduction of bacteria leads to genetically identical offspring

Genetic Modification and Insulin

• Insulin produced is identical to human insulin eliminating the Chance of rejection while animal derived may have side effects
• Also it can be massed produced

Genetic engineering also

• Insertion of genes into crop plants for herbicide and insect resistance and additional vitamins are benefits

Positive Traits from genetic engineering

• Crops are resistance to pesticides and herbicides and they can be used without harm to the crop
• can develop crops with much more vitamins such as golden rice .
• High production levels
• Can develop disease resistant crops
• Can develop crops with vigorous growth in normal conditions
• Height will be similar and easier to harvest
• ripening is the same time

Genetically Modified Crop Disadvantages

• Herbicides are made and insects
• Gene can pass from herbicide resistant crops to herbs or weeds leding to development of resistant weed populations
• Herbicide and insecticide crops may cause affect on human health
• Can enable the farmer to increase doses of herbicide and insecticide this increases pollution and Afffects biodiversity

Fermenters

• Fermenters are large steel vessels used to reproduce microorganisms by providing them with suitable conditions

Sterilization in Fermenters

• Sterilization is achieved using steam because chemicals can harm the required microorganisms and when the steam cools, the distilled water will not harm the microorganisms

Purpose of Sterilization

• Sterilization Prevents foreign microorganisms to not react with the organisms in the culture

Paddles

• used to Mixes the contents so that microorganisms can be more exposed to the nutrients
• They Keep the temperature even throughout the vessel

Water to change temperature

• Cold water is forced into the water jacket until reaching the required temperature

Fermenter material

• Stainless steel or alloys are used because microorganisms produce acids that are corrosive and can erode components

Fermenters and Enzymes

• Use Yeast, fungi or bacteria
• Sterilize and force into the vessel to multiply

Methodolgy With Fermenters

• Feedstock such as starch is sterilized and is introduced into the fermenter
• If enzymes are extracellular they are extracted from thr fitrate
• However, if they are intracellular the organisms are removed and added to water so they can rupture and the product is released/recovered

Antibiotics

• Using a sterilized vessel fungus can produce antibiotics with 4 steps
• Culture solution is then forced into the fermenter

Oxygen

• Oxygen is forced for respiration of the Penicillium mold

Temperature

• Temperature is important and must be maintained at 24°C because it allows the bacteria to grow

Harvest

• After about 40 hours fungi can produce penicillin
• Products from culture are harvested

Refine

• Penicillin is extracted from the water using organic solvents
• Then, they are evaporated leaving pure penicillin

Explore variation within species, including continuous and discontinuous types. Learn about the genetic and environmental factors influencing these variations. Understand the roles of mutation, meiosis, and adaptation in shaping populations, with a focus on antibiotic resistance.