Question

1. there are 3 types of polar bears: ones with thick coats, ones with thin coats and ones with medium coats. it is fall, soon to be winter. the temperatures are dropping rapidly and the bears must be kept warm, or they will freeze to death. many of the bears have had ~2 cubs each but due to the extreme temperatures, many mothers only have one cub left.

a. what bear will natural selection select against? _____________ for? _____________
darwins 5 points: identify the 5 points in the scenario above.
population has variations. ________________________________________________________
some variations are favorable. ______________________________________________________
more offspring are produced than survive.____________________________________________
those that survive have favorable traits. ____________________________________________
a population will change over time. _________________________________________________

Explanation:

• Natural Selection Against/For: In a cold environment (winter approaching), thin - coated bears would struggle to stay warm (selected against as they may freeze), while thick - coated bears are well - suited (selected for as they can better survive the cold).
• Darwin's 5 Points:
• Population has variations: There are three types of polar bears (thick, thin, medium - coated), showing variation in coat thickness.
• Some variations are favorable: Thick - coated is favorable for surviving the cold winter.
• More offspring are produced than survive: Bears have ~2 cubs each, but many mothers only have one left (due to extreme temperatures), so more are born than make it to survival.
• Those that survive have favorable traits: Surviving cubs (in the context of coat thickness for winter survival) likely have thicker coats (assuming the survival is related to coat thickness as a trait).
• A population will change over time: Over generations, if thick - coated bears are more likely to survive and reproduce, the proportion of thick - coated bears in the population will increase.

Answer:

a. Against: Thin - coated bear; For: Thick - coated bear
Darwin's 5 points:

• Population has variations: Three types of polar bears (thick, thin, medium - coated)
• Some variations are favorable: Thick - coated is favorable for cold survival
• More offspring are produced than survive: Bears have ~2 cubs each, but many mothers have only 1 left
• Those that survive have favorable traits: Surviving cubs (related to coat - thickness - for - survival trait)
• A population will change over time: Proportion of thick - coated bears may increase over generations