Causes of Evolution
Name two factors that can cause competition among organisms.
Limited resources like food, water, and shelter.
Give an example of a biotic factor that affects populations.
Number of predators or spread of bacteria.
What is the term for bacteria becoming less affected by antibiotics over time?
Antibiotic resistance.
Why is genetic diversity important for evolution?
It allows populations to adapt to changing environments.
What is the significance of antibiotic resistance in bacterial populations?
It shows how bacterial populations can evolve to survive treatments, posing challenges for humans.
What is the term for the process where traits that improve survival and reproduction become more common over generations?
Natural selection.
What happens when an abiotic factor like climate changes drastically?
Populations adapt over many generations through changes in gene frequency thanks to natural selection (assuming an advantageous variation exists within the population) or may face extinction.
How do mutations contribute to bacterial resistance?
They create genetic variation that may allow some bacteria to survive antibiotics.
What is the role of random genetic mutations in evolution?
They create new traits that may provide advantages.
How can humans maintain a healthy microbiome?
By limiting unnecessary antibiotic use and eating diverse, healthy foods.
Share an example of something that could force the evolution of a population of organisms over multiple generations.
Any selective pressure would be an appropriate answer (Disease, Changes to Environment, Changes to Resources Available, etc...)
Why is genetic variation important in the process of natural selection?
It provides the raw material for advantageous traits to be selected.
Why is it important to finish a full course of antibiotics?
To prevent surviving bacteria from reproducing and spreading genes for resistance.
What are the two source of heritable variation in populations?
Genetic mutations and new gene combinations from sexual reproduction.
How do bacteria communicate for the survival of their population?
Quorum sensing (feedback mechanism that starts or stops bacterial reproduction based on the number of bacteria around)
What happens to organisms with advantageous traits in a population?
They survive and reproduce more successfully, increasing those traits' frequency.
How does the frequency of a beneficial gene change over time in a population?
It increases, leading to the adaptation of the population.
What does the term "biofilm" describe in bacterial populations?
A cooperative structure that protects bacteria from harsh conditions.
How does sexual reproduction contribute to genetic variation?
By combining different genes from two parents.
In what ways do bacteria cooperate with each other for the survival of their population?
One way that bacteria can cooperate is by excreting (releasing) something into the environment that can benefit not only themselves, but also their neighboring cells that are often genetically related to them. This could be an enzyme that breaks down antibiotics, toxins that kill off competitors, or compounds that assist in acquiring nutrients. They can also do biofilm formation (a protective slimy layer secreted by bacteria that creates a large group of bacteria huddled together under the slime for protection).
Explain the idea of a "heritable genetic variation"
Genes can be passed from generation to generation. The same is true for genes that are mutated/varied from what is typical. The fact that variations can be inherited contributes to the long-term species' diversity and allows for certain variations to be selected for by natural selection.
How does the increase in advantageous traits occur in a population over generations?
Through differential survival (some individuals survive; some don't) and reproduction (the survivors reproduce) linked to environmental pressures.
How does antibiotic resistance relate to the process of natural selection?
Bacteria with resistance genes survive and reproduce, increasing resistance in the population.
What happens when a population lacks genetic diversity?
It may struggle to adapt to environmental changes, risking extinction.
How can bacteria support the health of their human host?
All of the bacteria and other microorganisms we host are collectively called the microbiome. Everyone has a slightly different microbiome and your microbiome can change throughout your life or even from month to month. One important component of the microbiome is that these bacteria often make specific molecules called metabolites that can assist their human host in obtaining nutrients and energy, proper immune function, and protection against pathogens.