Week 28

Monday & Tuesday, March 23 & 24, 2020: For first lesson of Week 28, we will revisit the concept of taxonomy, first introduced by Carl Linneaus back in 1735.  Visit the HHMI Creating Phylogenetic Trees from DNA Sequences web page.  Download and complete the worksheet by working through the Click and Learn activity.

For your work today, create a new Google Doc titled with your name – Week 28.  Share the Doc with Mr. Swart.  Write answers to the worksheet questions in your Week 28 Google Doc into a section titled “Creating Phylogenetic Trees from DNA Sequences Worksheet Answers”.

Wednesday-Thursday, March 25-26, 2020: Over the past few weeks, we have acquired a significant amount of evidence for evolution:

  • Natural selection (the common ancestry of brown bears and polar bears; dinosaurs and chickens)
  • Artificial selection (humans selecting for desired traits, such as dog breeding)
  • 13 different finch species now inhabiting the Galapagos Islands all evolving from a common Mainland finch ancestor

As we continue learning about evolution, we must expand our view to consider the concept of co-evolution:

  • Co-evolution is the idea that organisms do not evolve in a vacuum.
  • The term co-evolution is used to describe cases where two (or more) species reciprocally affect each other’s evolution.
  • Plants and insects represent a classic case of co-evolution — one that is often, but not always, mutualistic. Many plants and their pollinators are so reliant on one another and their relationships are so exclusive that biologists have good reason to think that the “match” between the two is the result of a co-evolutionary process.
  • For more about co-evolution, visit the evolution.Berkeley.edu website!

Important Vocabulary:

  • Host: an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter.
  • Bacteria: microscopic living organisms, usually one-celled, that can be found everywhere. They can be dangerous, such as when they cause infection, or beneficial, as in the process of fermentation (such as in wine) and that of decomposition.
  • Virus: Any of various simple submicroscopic parasites of plants, animals, and bacteria that often cause disease and that consist essentially of a core of RNA or DNA surrounded by a protein coat. Unable to replicate without a host cell, viruses are typically not considered living organisms.
  • Infection: Invasion and multiplication of an infectious agent in body tissues of the host and may lead to clinical symptoms or local cellular injury as a result of competition in metabolism, production of toxins, intracellular replication, or antigen antibody response.
  • Symbiosis: the interaction between two different organisms living in close physical association.
  • Symbiotic Relationships:
    • Mutualism: symbiosis that is beneficial to both organisms involved.
    • Commensalism: an association between two organisms in which one benefits and the other derives neither benefit nor harm.
    • Parasitism: a non-mutual symbiotic relationship between species, where one species, the parasite, benefits at the expense of the other, the host.

For your work today, create a new section in your Week 28 Google Doc titled “Biological Relationships Vocabulary”.  Then, for each of the 12 words from this lesson highlighted in red bold text, research your own examples of these biological relationships and write up your work in your Week 28 Google Doc.  Include source citations as appropriate.

Friday, March 27, 2020: Yesterday you learned about the many different ways organisms can live together.  Today we will focus on the type of symbiotic relationship called parasitism.  We will begin by watching a National Geographic video about zombie parasites.  The presenter, Anand Varma, applies his expertise in photography to the study of parasites.  Mr. Varma travels the world collecting specimen for study, and his ability to apply biological concepts to his work, think creatively, and drive to overcome failure make him and his work truly remarkable.

Next, read the article Meet the Parasites That Control Human Brains.  In your Week 28 Google Doc, create a section titled “Zombie Parasites” and share your thoughts on the following questions:

  • Why do zombie parasites persist?
  • What niche do they fill within an ecosystem?
  • Think about behaviors you see in yourself and those around you.  Ever wonder why people do what they do?
  • Does the existence of zombie parasites cause you to think differently about people and their actions?

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