3.3a Evolution as a Practical Idea

Question 1: evolution to occur?

• There must be a limitation on resources and a competition for those resources

• Organisms within a population must be variable.

• Organism variability must be heritable.

The essence of Darwin and Wallace’s theory is that natural selection will occur if what three conditions are met?

a struggle for existence, variation and inheritance

• additionally, evolution is a practical subject with relevance to human health and human economic activity (in particular) agriculture.

Which of the following below are examples of evolution relevant to human health and agriculture?

• The spread of antibiotic resistant bacteria through overuse of antibiotics B.

• The advance of metastatic cancer (resistance to chemotherapy) within an individual

• The development and spread of infectious viruses

• The appearance and challenge of ‘super weeds’ – plants that herbicides cannot contain

• The development of resistance in insects to insecticide chemicals

What has happened to Infectious bacteria in recent decades?

They have increasingly become resistant to antibiotics, limiting our ability to cure infections.

The advance of metastatic cancer (resistance to chemotherapy) within an individual is an example of what?

an example of natural selection at work

growing problem for industrial agriculture example:

the evolution of herbicideresistant ‘super weeds’

• Pig weed has become increasingly resistant to glyphosate in recent years:

The development and spread of infectious viruses is another example of what?

example of how evolution impacts human life

How have insects also become resistant to many insecticides?

natural selection and evolution.

• Malaria-carrying mosquitoes are evolving resistance to insecticides:

• Cockroaches have evolved a resistance to insecticides and a distaste for sweet baits

What is the Red Queen's hypothesis?

hypothesis in evolutionary biology proposed in 1973, that species must constantly adapt, evolve, and proliferate in order to survive while pitted against ever-evolving opposing species

• under his hypothesis, species have to "run" or evolve in order to stay in the same place, or else go extinct

How can we stay ahead of these evolving agents – threats to human health and

prosperity?

• Use of combination therapies: evolving agents may not be able to develop resistance to several treatments given at the same time (with different modes of action).

• Sequential treatments: adaptive therapy; Evolutionary theory and experiments predict that evolving agents are often able to adapt easily to a singular, continuous selective pressure – so in this method, combination therapies are administered one drug at a time.

• Use of evolving agents as a counter-response: eg phage therapy, ‘natural’ beekeeping, etc…

• Monitoring of evolving populations to aid in development of countermeasures (eg flu and pandemic tracking, vaccine preparation)