Vocabulary
What does it mean if a trait is "advantageous?"
It's a trait that helps the organism survive and reproduce
What happens to the frequency of a helpful trait over time?
A helpful trait becomes more frequent (common) over generations
Give an example of variation within a species
Different heights, different speeds, being antibiotic resistant, different size teeth, etc.
Plants make their own fuel (glucose) as well as oxygen. They take in carbon dioxide, water, and sunlight to do this!
What does it mean if a trait is "heritable?"
A heritable trait is passed on to offspring via DNA (genes)
If an environmental change caused a loss of biodiversity, what would the graph look like?
The entire population would decrease or species would go extinct
How do plants get carbon dioxide?
They take it in through their stomata (tiny pores in the leaves)
What does it mean if an organism is "resistant" to something like an antibiotic or pesticide?
Resistant = not killed by the substance
A species started with 75% large ears and 25% small ears. After many generations and environmental change, the population ended up 20% large ears and 80% small ears. Which of the traits was advantageous in the new environment?
Small ears was advantageous because the frequency of small ears increased. Small ears might retain less heat or be less attractive to predators.
If there is an environmental challenge, what does it mean when "the best suited organisms are more likely to survive?"
Organisms with certain traits have a better chance of living long enough to reproduce (because those traits help them)
How do a plant's stomata maintain homeostasis?
The stomata close to keep water from leaving the plant when it's hot and dry. If it's cool and not too dry, the stomata stay open to let in carbon dioxide.
Having different traits in a population (different colors, sizes, abilities, etc.)
If no members of a species have traits that enable it to survive an environmental disruption, what happens?
The species goes extinct (dies off)
If there is an environmental challenge, what does it mean when "helpful traits are more likely to be passed down to the next generation?"
If a trait helps an organism survive/reproduce and the trait is genetic (in DNA), offspring of survivors are likely to inherit that trait
How does the pancreas maintain homeostasis?
If blood glucose is high, the pancreas releases insulin. Insulin is a hormone that causes blood sugar levels to decrease. The blood sugar levels decrease because insulin tells body cells to take in more glucose.
(The pancreas also releases glucagon, which causes blood glucose levels to rise if they are too low)
Does an individual organism evolve by getting new traits?
NO!!! A population can evolve when certain traits are passed down more often, but organisms can't change their genes.
A species of insects has an average wingspan of 1.5 inches. If they need to squeeze into small spaces to hide, how will the average size change?
What does it mean if a species evolves a trait over time?
Over many generations, helpful traits become more common because the organisms with those traits survive and pass them on. An organism CANNOT change its genes/traits.
What is a positive feedback mechanism?
A positive feedback mechanism is a cycle that keeps going. The body's response causes more of the same response.