Chapter 7

• An adaptation helps an organism survive and reproduce in a particular environment.
• Adaptations can be structural/physical, such as webbed feet, sharp claws, scales, large beaks, talons.
• Adaptations can also be behavioural, including migration, hibernation, camouflage, dogs pant to cool down.
• Adaptations can be physiological, with many fish and reptiles being cold blooded to cope with living in a cold-water environment, and snakes and spikers producing venom to paralyze their prey and make them easier to digest.
• Adaptations are the result of gradual, incremental changes over time that aid survival and reproduction.
• The adaptations we can observe now are the variations (structures, behaviours, processes) that enhanced the survival and reproduction of the organism’s ancestors.
• Many variations are unsuccessful in an environment but these are eliminated.
• Variation within a species is increased through sexual reproduction.
• Alleles are shuffled into new combinations through Crossing Over and Independent Assortment and Segregation.
• New variations arise from mutations in DNA.
• Mutations can be harmful, neutral, or beneficial.
• Beneficial Mutations provide a selective advantage to an individual.
• Mutations in the cells that form Gametes are more significant.
• Eukaryotic cells contain more genetic information than somatic cells.
• Diversity exists within most populations.
• Some individuals have allele combinations that provide an advantage over others.
• Individuals better at surviving have more offspring who inherit their 'better' genes.
• Over time, the process of natural selection causes the characteristics of the population to gradually change.
• Natural selection is a process by which species that are best adapted to their environment survive and reproduce.
• Natural selection results in the changing of characteristics in a population of organisms over time.
• Natural selection does not anticipate the change in the environment and thus has no direction or purpose.
• There are times when one trait may have no relevance for survival until a selective pressure turns that trait into a selective advantage.
• Fitness is the ability of an organism to reproduce and create viable offspring; passes on its advantageous genes to its offspring; those offspring will survive long enough to reproduce as well.
• Fitness is measured by viable offspring.
• The higher the reproductive rate, the greater the degree of fitness.
• When an organism has a high degree of fitness it is referring to its trait having a selective advantage in a particular environment.
• Selective pressures can be biotic (living factors) or abiotic (non-living factors).
• Artificial selection is the identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations.
• Selective pressure exerted by humans on populations as a means to improve or modify particular desirable traits.
• Humans have learned how to selectively breed certain organisms.
• Selective breeding and artificial selection are a type of BIOTECHNOLOGY.
• Natural selection, the ENVIRONMENT plays the role; in artificial - HUMANS play the role.
• The continued selection for bigger, starchier kernels by Native North American’s (over 10,000 years) developed todays modern corn cob.
• Increase nutritional value.
• Increase food production/harvest, thus increasing the economy for countries.
• To be drought resistant and pest resistant (allowing seasonal harvest).
• Artificial selection can have negative consequences such as Monoculture: Selective breeding in plants, has the tendency to produce genetically identical plants.
• Reduced genetic diversity makes crops susceptible to mass damage/entire crop failure because of disease or pests.