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13.1: Introduction - Biology

13.1: Introduction - Biology


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Module 11 – Diversity of Life I

Introduction

In Module 3, we defined cells as the basic unit of life and then went on to categorize all cells into one of two groups: eukaryotes or prokaryotes. What allows for that diversity?

In the these next two modules, we begin to explore the diversity of life and the three domains of life: Archea, Bacteria, and Eukarya. In this module, we will scan the following groups of organisms:

  • bacteria
  • archea
  • protists
  • fungi

We will even take a look at viruses, which are not classified as living things 1 .

Learning Outcomes

This module addresses the following Course Learning Outcomes listed in the Syllabus for this course:

  • Demonstrate knowledge of biological principles.
  • Demonstrate knowledge of scientific method.
  • Communicate scientific ideas through oral or written assignments.
  • Interpret scientific models such as formulas, graphs and tables.
  • Demonstrate problem solving methods in situations that are encountered outside of the classroom 1 .

Module Objectives

Upon completion of this module, the student will be able to:

  • Define the three domains of life: Archea, Bacteria, and Eukarya.
  • Describe several ways microbes are essential to life.
  • Describe how viruses “hijack” living cells and state the purpose of this “hijacking.”
  • Define several types of beneficial bacteria.
  • Describe several types of bacteria that have ill effects on humans.
  • Answer the questions:
    • What traits would an organism have in order to be classified as a protist?
    • What protists are able to undergo photosynthesis?
  • Define autotroph and heterotroph.
  • Define pathogen , extremophile , mutualism , and binary fission.
  • Describe several roles for fungi in society and nature.
  • Define lichen , hyphae , sessile , spore , yeast , mutualism .
  • Answer the questions:
    • How do fungi obtain nutrients?
    • How is this similar/ dissimilar to the way humans obtain nutrients? 1

Introduction

According to the United Nations Office on Drugs and Crime, approximately 95% of those who commit homicide are men. While behavior is shaped by the environment one grows up and lives in, genetics also play a role. For example, scientists have discovered genes that appear to increase one’s tendency to exhibit aggressive behavior. One of the genes, called MAOA, is located on the X chromosome. In one recent study involving a group of male prisoners in Finland, scientists found that the prisoners who inherited a variant of this gene were between 5% and 10% more likely to have committed a violent crime. Men only have one copy of the gene, since men only have one X chromosome. Women, however, have two copies of the X chromosome and therefore two copies of the gene. Therefore, women who inherit the variant allele will most likely also have a normal allele to counteract its effects. It is important to note that many men inherit the variant copy of MAOA and only some commit violent crimes. The environment seems to play a much more critical role. You can read more about nature/nurture roles in crime in this article.

Teacher Support

Before students begin this chapter, it is useful to review these concepts: DNA and chromosome structure relationships among DNA, genes, and chromosomes overview of the steps of mitosis and meiosis overview of independent assortment ploidy (haploid versus diploid).


Chapter 13: Introduction to Animal Reproduction and Development

Figure 13.1 Female seahorses produce eggs that are then fertilized by the male. Unlike with almost all other animals, the young then develop in a pouch of the male seahorse until birth. (credit: “cliff1066″/Flickr)

In the animal kingdom, each species has its unique adaptations for reproduction. Asexual reproduction produces genetically identical offspring (clones), whereas in sexual reproduction, the genetic material of two individuals combines to produce offspring that are genetically different from their parents. During sexual reproduction the male gamete (sperm) may be placed inside the female’s body for internal fertilization, the sperm may be left in the environment for the female to pick up and place in her body, or both sperm and eggs may be released into the environment for external fertilization. Seahorses provide an example of the latter, but with a twist (Figure 13.1). Following a mating dance, the female releases eggs into the male seahorse’s abdominal brood pouch and the male releases sperm into the water, which then find their way into the brood pouch to fertilize the eggs. The fertilized eggs develop in the pouch for several weeks.


Watch the video: μάθημα 39 Κυτταρική Διαίρεση part 5, Μείωση εισαγωγή. Βιολογία Γ λυκείου, Biology maniax. (May 2022).