Video- adaptation, mutations, natural selection n

• Adaptation


  A trait that makes an organism more suited to its environment
• Adaptation


  The process by which a population becomes dominated by organisms that are suited to their environment
• Natural selection


  Organisms with beneficial heritable traits increase their share of the gene pool in the population because they're more likely to mate and produce offspring
• Fitness


  A measure of an organism's ability to survive and reproduce in its specific environment
• Adaptations


  Make the organisms better suited to survive and reproduce because they're better suited to the specific environmental context that they live in
• Types of adaptations


  • Anatomical (changes to physical structures)
  • Physiological (changes in the function of structures)
  • Behavioral
• Honeybee adaptations


  • Africans construct nests right out in the open air
  • North Americans prefer to live inside protected structures
• Traits that helped African honeybees survive were liabilities in much of North America
• Natural selection has to work with what an organism has
• Remarkable adaptations


  • Pistol shrimp can slam their claws shut to implode water and knock nearby fish unconscious
  • Honeybees can vibrate their flight muscles to create a biological convection oven to cook predators
  • Parasitic wasps that live inside other parasitic wasps inside caterpillars
  • Hornets with solar panel-like patches on their abdomen
• Variation - Differences between individuals within a population
• Adaptation - A characteristic that helps an organism to survive and reproduce in its habitat
• Natural Selection is the process by which organisms better adapted to their environment tend to survive and reproduce more than those less well adapted.
• Genetic variation - Changes in DNA sequence
• Heritable variation - Variation that is passed from one generation to another
• Heritable variation - Variation passed from parent to offspring through genes
• Environmental variation - Variation caused by environmental factors such as diet or climate
• Genetic variation - Variation caused by differences in genes
• Disorders suffered by some members of the human race

  • Premature aging
  • Growing a bark-like substance out of your skin
  • Having facial hair like a werewolf
• Genetic mutation


  Where we grow and develop in the womb is controlled by our DNA, small sections of DNA called genes carry the code telling the body how to build itself
• Usually this DNA code works fine but sometimes these genes carry mistakes in their code, these mistakes are known as mutations
• Mutations may have no effect, they may be beneficial, or they may be harmful
• If the mutation is beneficial


  The mutated individual will have a better chance of surviving and reproducing, with all the offspring benefiting from this mutation too
• If the mutation is harmful


  The individual may not be able to survive and reproduce
• Natural selection


  1. Non-beneficial and harmful genes are eventually weeded out of a population

  2. Species tissues evolve through a slow process of natural selection so that only the beneficial mutations are incorporated into a population whilst the harmful ones are removed
• Sickle cell disease


  A genetic mutation that is harmful to humans, it causes the hemoglobin molecules inside red blood cells to crystallize, making the red blood cells an abnormal sickle shape which makes it harder for them to carry and release oxygen
• Individuals with sickle cell disease are at risk of a whole host of medical problems such as heart attack and stroke
• As recently as the 1970s, sickle cell sufferers did not live much beyond the age of 14, usually before they had a chance to reproduce and pass on their defective genes to the next generation
• Sickle cell carriers are more immune to malaria than those who aren't

  They are more likely to survive and reproduce, thus passing on the sickle cell trait
• Genes carry the code which tells our bodies how to develop, and sometimes this code changes, which is called mutation
• Mutations happen all the time, they can be beneficial, neutral, or harmful in their effects
• Over time and as a result of ongoing mutations, species evolve and change through natural selection