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Evolution

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  • Anatomy/Anatomical
    Different organisms share similar structures that have very different functions, or have remnants of structures/organs that had a function in the past.
  • To the right showing various wings is an example of what type of structure?
    Analogous structures (different structures, similar functions)
  • What are homologous structures? Describe an example
    Homologous structures are physical structures that organisms from different species have in common. They are called HOMOlogous because they have the SAME struct
  • Explain below how we use Biogeography as evidence for evolution.
    We look at how organisms are distributed around the world and can see evidence of how different environments select for different features. For example: when Da
  • Would a fossil from layer F be older or younger than a fossil from layer B
    Younger- it sits on top of B on both sides of the fault line.
  • The picture shows a prehistoric mammal called Ambulocetus. This animal lived almost 50 million years ago in coastal waters. It used its back legs to swim in water and front legs to crawl on land. Scientists think that the whale evolv
    Examination of the body structures of both animals
  • Fossils
    Fossil organisms found in bottom (older) layers are more primitive than those in the upper (newer) layers; often times, these extinct fossils resembled modern l
  • GENETIC DRIFT
    Random change in the allelic frequencies in a population that results from chance. Bottleneck effect: some natural disaster (like a volcano) kills the majority
  • Which layer is the youngest?
    R
  • Embryological/Developmental
    During the early stages of life, embryos of very different organisms appear to be very similar. As they continue to develop, they become increasingly different.
  • What will happen to species when their environment suddenly changes due to natural disaster? How will that be reflected in the fossil layer (hint: think about the dinosaurs
    A very small number of them will survive or the entire species will die off. There will be a distinct part of the fossil layer that has them, then they will dis
  • Describe what bottleneck effect is.
    Eliminating a large portion of the population (catastrophic event) and few genetic variations are left remaining
  • Describe what gene flow is. Give an example of gene flow occurring in a bird species.
    The random movement of individuals between populations (of the same species) and it increases genetic variation
  • Some adaptations can include camouflage and mimicry. State how each help an organisms survive below: Mimicry
    the ability of an organism/species to look like a member of a different, usually poisonous species. This protects them from predators, who don’t want to eat som
  • How do we define evolution? **Be sure to include in your definition whether individuals evolve or populations**
    Evolution is the change in the traits of a population or species over time. NOT an individual.
  • In Madagascar scientists have discovered a moth, Xanthopan morganii praedicta, that has a 30.5 cm proboscis and feeds from and pollinates Darwin’s orchid, Angraecum sesquipedale. The orchid has a nectar-producing tube that is 27.9 cm long.
    The moth has little competition for food
  • How do we define a species?
    A group of organisms capable of interbreeding (mating) and producing fertile offspring (their kids can have kids).
  • GENE FLOW
    The random movement of individual organisms between two populations of a species. They are able to bring their unique combination of traits to the new populatio
  • What type of interaction occurs when limited resources are available for organism to use? How does this interaction impact an organism’s ability to survive and reproduce?
    Competition occurs when limited resources are available. Organisms that “win” the competition are able to survive and reproduce, organisms that “lose” the compe
  • Who was Charles Darwin?
    A 19th century naturalist (scientist who studies nature) who studied the differences found in species
  • Describe natural selection AND describe an example of natural selection
    Natural selection is a process that occurs when: A population experiences overproduction of offspring. The members of the population have genetic variation. So
  • Do these organisms have a common ancestor?
    No
  • What did Charles Darwin do and where did he do it?
    He researched organisms on the Galapagos Islands. He is known for his studies of finch beak shape/size.
  • What is the ultimate result of natural selection? (HINT: Your explanation should include the term “allele frequency”/It may act on phenotypes over time; however, think about what is it ultimately changing?)
    The ultimate result of natural selection is that traits (alleles) that are NOT suited for the environment will die off, or the allele frequency will decrease. T
  • s evolution studied and occurring at the population level or at the level of the individual organism?
    The population level.
  • How do adaptations contribute to survival and reproductive success? List an example.
    Having an adaptation that is suited to an environment means that the organism is well “fit” for its environment, or able to survive and reproduce. An example wo
  • What adaptation seems to increase the fitness of the cacti on the right? How do you think this adaptation increases the ability of cacti on the right to survive and reproduce?
    Having spines. This will increase its fitness because animals will not want to eat it, so it will survive and reproduce.
  • Figure 4 shows the situation several months later. What has happened?
    The deer has eaten off of the plant that has no spines, leaving the one with spines alone. The smooth cactus does not produces flowers the next year and dies of
  • What do we mean by the “gene pool”?
    The gene pool is all of the possible variations of a gene. For example: the gene pool for human hair is blonde, brown, black, red, and grey/white. There are sha
  • Which layer is the oldest?
    I
  • NATURAL SELECTION
    The gradual (slow) change in a population’s characteristics over time, due to environmental pressures. Does this process increase or decrease genetic variatio
  • MUTATION
    A change in DNA to produce a new trait. Ex: blue eyes are a mutation from the original brown eyes. Does this process increase or decrease genetic variation? I
  • Describe what the founder effect is.
    When a small group, from a large population, of individuals establish a new population in a new location.
  • Some adaptations can include camouflage and mimicry. State how each help an organisms survive below: Camouflage
    the ability of an organism to blend in with its environment. This helps the organism hide from potential predators (so they don’t get eaten) and prey (so they
  • Biogeography
    Different habitats favor different traits and can establish separate populations that have a common ancestor.
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