Anthro 7 Midterm Key, Winter 1998
I strongly discourage re-grade requests. Any such request must be made in writing and
must explain why you think your answer deserved more points than it received. If you
request a re-grade, we may re-grade all your answers, not just the one that want re-
graded, and we may subtract points rather than add them.
Here are model answers to the midterm questions:
(1) According to Darwin's theory, what three conditions must occur in order for natural
selection to occur? Describe each condition in a phrase or a complete sentence, not a
More offspring are produced than can survive.
Organisms within populations vary, and this variation affects their
ability to survive and reproduce.
Variation is heritable, i.e. offspring tend to resemble their parents.
(2) Are an organism's genes more like a
, or more like a
? Explain your
answer. As part of your explanation, describe the relevant difference between a (literal)
blueprint and a (literal) recipe.
It's more like a recipe. The components of a recipe (words, letters)
don't map one-to-one on to the components of, e.g. a cake (flavor,
texture). Instead, a recipe specifies which processes to perform on
which ingredients in what order. Similarly, the genes, which code
directly only for protein synthesis, specify a complex sequence of
steps performed on various substances. In contrast, the components of a
blueprint (lines, spaces) do map one-to-one on to the components of,
e.g. a house (walls, rooms). The flow of information between blueprint
and house is reversible, but the flow of information between recipe and
cake is not reversible.
(3) You are a breeder of one-humped camels. Year after year, you breed your animals,