Question

snails eaten vs. snail shell color
snails eaten
references:
prolineserver. (2007, june 1). file:snail anim.gif. wikimedia commons. https://commons.wikimedia.org/wiki/file:snail_anim.gif
sanches, d. (2008). gaviao - caramujeiro (rostrhamus sociabilis) photograph. wikimedia commons, kimedia.org/wiki/file:flickr_-_dario_sanches_-_gavi%c3%83o - caramujeiro_(rostrhamus_sociabilis)_(used under cc by - sa 2.0)
multiple choice

1. which statement about natural selection is true?

a. helpful traits always become more common in a population over time.
b. only animals with helpful traits will be able to survive and reproduce.
c. all animals have an equal chance of reproducing over time.
d. helpful traits can become more common in a population over time.
e. the largest animals in a species always have an advantage in surviving.
multiple choice

1. based on figure 4, which of these statements correctly describes the likely effect of snail populations?

a. the next generation of snails will have no light - colored shells.
b. over time the population of dark - colored snails will decrease.
c. the snail kites will not affect the next generation of snails
d. over time the population of light - colored snails will decrease.

Explanation:

Question 1

To determine the correct statement about natural selection, we analyze each option:

• Option A: Helpful traits don't always become more common; it depends on fitness and environment. Eliminate A.
• Option B: Animals with helpful traits (increasing survival/reproduction) are more likely to pass them on, so these traits become more common over time. This aligns with natural selection.
• Option C: Reproduction chance isn't equal; traits affect survival/reproduction odds. Eliminate C.
• Option D: Helpful traits become more common, not less. Eliminate D.
• Option E: Largest animals don't always have survival advantage (e.g., energy needs, predation). Eliminate E.

From the bar graph, lightest - shelled snails are eaten least, darkest most. So:

• Option A: Next generation will have light - colored shells (since they survive better), not no light - colored. Eliminate A.
• Option B: Dark - colored snails are eaten more, so their population will decrease over time (fewer survive to reproduce). This is correct.
• Option C: Snail kites (predators) do affect snail populations via predation. Eliminate C.
• Option D: Light - colored snails survive better, so their population will increase, not decrease. Eliminate D.

Answer:

B. Only animals with helpful traits will be able to survive and reproduce.

Question 2