- analyze the economic and environmental advantages and disadvantages of an artificial selection technology, and evaluate the impact of environmental changes on natural selection and endangered species
- investigate evolutionary processes, and analyze scientific evidence that supports the theory of evolution
- demonstrate an understanding of the theory of evolution, the evidence that supports it, and some of the mechanisms by which it occurs
BIG IDEAS
- Evolution is the process of biological change over time based on the relationships between species and their environments.
- The theory of evolution is a scientific explanation based on a large accumulation of evidence.
- Technology that enables humans to manipulate the development of species has economic and environmental implications.
UNIT TASK PREVIEW
In this Unit Task you will choose a current topic in applied evolutionary biology from medicine, conservation biology, agriculture, or from a field of your choosing. You will complete an analysis of the application, reviewing the evolutionary principles at work, what the theory predicts, and how the theory is applied to the situation in question.
The Unit Task is described in detail on page 378. As you work through this unit, look for the Unit Task Bookmarks to see how information in the section relates to the Unit Task.
Print Page 277
FOCUS ON STSE
IN PURSUIT OF POISONS
Poisons can make powerful medicine. At first this might sound like a contradiction. How can a poison be of medical benefit? The answer lies in what ails you. We use a variety of drugs to kill infectious bacteria and parasitic organisms that have invaded our bodies. We also try to kill our own cells if they have become cancerous and are dividing out of control. Antibiotics, chemotherapy drugs, and other medicines are poisonous to their intended target. How do scientists go about finding these "poison pills"?
Many poisons are produced by living organisms. In their search for these poisons, evolutionary biologists often look for situations in which there is an ongoing evolutionary "arms race" between predator and prey or between pathogen and host. In these situations a species may have evolved chemical defences to deter a predator or to fight off infectious organisms.
The tropical rainforests of Central and South America are home to some dramatically coloured poison dart frogs. Their bright coloration serves as a warning to would-be predators that these frogs contain poisons. In addition to the poisons these particular frogs use to ward off predators, all frogs produce antimicrobial chemicals in their skin to resist infections. More than 100 of these chemicals have been isolated, and at least one is able to kill some strains of highly drug-resistant bacteria. Researchers believe these substances could become the basis for a powerful new generation of antibiotics. Ironically, the existence of many of these same frog species is threatened by a serious fungal skin disease. The fungus is being introduced to new ecosystems by human activity. Without previous exposure to the fungus, many frog species have not had an opportunity to evolve a chemical defence against it.
Scientists apply evolutionary or Darwinian thinking to all aspects of healthcare and indeed to all aspects of biology. As you will learn, the theory of evolution provides important insights and informs our understanding of individuals, species, communities, and entire ecosystems. Evolutionary biology is a vital tool for maintaining and enhancing our own health as well as that of the diversity of life on Earth.
Questions
1. Many potent medicines are derived from plant toxins, while relatively few come from animal sources. (a) Why might plants have evolved more poisons than animals? (b) Would you expect plant poisons to be more concentrated in leaves, fruits, or roots? Explain your reasoning. (c) Fruits and roots make up a larger portion of a typical human diet than leaves. Are you surprised? Explain.
2. Given that many drugs are actually biological poisons designed to kill certain types of cells, is it surprising that many drugs have adverse side effects? What does this suggest about the challenges of developing safe and effective drugs to combat disease?
3. When exposed to sunlight, human skin produces vitamin D, an extremely important compound. Biologists are concerned that lifestyle changes could cause widespread vitamin D deficiency. How does this concern reflect Darwinian thinking?
4. Some species of Amazonian snakes are able to eat poison dart frogs. How does this illustrate the concept of an evolutionary arms race?
OVERALL EXPECTATIONS
- analyze the economic and environmental advantages and disadvantages of an artificial selection technology, and evaluate the impact of environmental changes on natural selection and endangered species
- investigate evolutionary processes, and analyze scientific evidence that supports the theory of evolution
- demonstrate an understanding of the theory of evolution, the evidence that supports it, and some of the mechanisms by which it occurs
BIG IDEAS
- Evolution is the process of biological change over time based on the relationships between species and their environments.
- The theory of evolution is a scientific explanation based on a large accumulation of evidence.
- Technology that enables humans to manipulate the development of species has economic and environmental implications.
UNIT TASK PREVIEW
In this Unit Task you will choose a current topic in applied evolutionary biology from medicine, conservation biology, agriculture, or from a field of your choosing. You will complete an analysis of the application, reviewing the evolutionary principles at work, what the theory predicts, and how the theory is applied to the situation in question.
The Unit Task is described in detail on page 378. As you work through this unit, look for the Unit Task Bookmarks to see how information in the section relates to the Unit Task.
Print Page 277
FOCUS ON STSE
IN PURSUIT OF POISONS
Poisons can make powerful medicine. At first this might sound like a contradiction. How can a poison be of medical benefit? The answer lies in what ails you. We use a variety of drugs to kill infectious bacteria and parasitic organisms that have invaded our bodies. We also try to kill our own cells if they have become cancerous and are dividing out of control. Antibiotics, chemotherapy drugs, and other medicines are poisonous to their intended target. How do scientists go about finding these "poison pills"?
Many poisons are produced by living organisms. In their search for these poisons, evolutionary biologists often look for situations in which there is an ongoing evolutionary "arms race" between predator and prey or between pathogen and host. In these situations a species may have evolved chemical defences to deter a predator or to fight off infectious organisms.
The tropical rainforests of Central and South America are home to some dramatically coloured poison dart frogs. Their bright coloration serves as a warning to would-be predators that these frogs contain poisons. In addition to the poisons these particular frogs use to ward off predators, all frogs produce antimicrobial chemicals in their skin to resist infections. More than 100 of these chemicals have been isolated, and at least one is able to kill some strains of highly drug-resistant bacteria. Researchers believe these substances could become the basis for a powerful new generation of antibiotics. Ironically, the existence of many of these same frog species is threatened by a serious fungal skin disease. The fungus is being introduced to new ecosystems by human activity. Without previous exposure to the fungus, many frog species have not had an opportunity to evolve a chemical defence against it.
Scientists apply evolutionary or Darwinian thinking to all aspects of healthcare and indeed to all aspects of biology. As you will learn, the theory of evolution provides important insights and informs our understanding of individuals, species, communities, and entire ecosystems. Evolutionary biology is a vital tool for maintaining and enhancing our own health as well as that of the diversity of life on Earth.
Questions
1. Many potent medicines are derived from plant toxins, while relatively few come from animal sources.
(a) Why might plants have evolved more poisons than animals?
(b) Would you expect plant poisons to be more concentrated in leaves, fruits, or roots? Explain your reasoning.
(c) Fruits and roots make up a larger portion of a typical human diet than leaves. Are you surprised? Explain.
2. Given that many drugs are actually biological poisons designed to kill certain types of cells, is it surprising that many drugs have adverse side effects? What does this suggest about the challenges of developing safe and effective drugs to combat disease?
3. When exposed to sunlight, human skin produces vitamin D, an extremely important compound. Biologists are concerned that lifestyle changes could cause widespread vitamin D deficiency. How does this concern reflect Darwinian thinking?
4. Some species of Amazonian snakes are able to eat poison dart frogs. How does this illustrate the concept of an evolutionary arms race?
October 26th, 2017
Chapter 7
November 9th, 2017
Chapter 8
UNIT PROJECT - due Nov. 29, 2017
*UNIT PROJECT MARKING SCHEME*
McGraw-Hill Ryerson Evolution slides:
Chapter 7
Chapter 8
Chapter 9