Text questions: Chapter 3

Question 1

Explain, using songbirds (Passeriformes) to illustrate, how unique characters can indicate if taxa are monophyletic (= evolved from common ancestor).

Answer 1

Unique characters can define related groups. For example species of the passerine order have helical shaped sperm and a preen gland with a unique structure. They also have specialized perching feet with a large hallux, uniquely arranged tendons, and simplified foot muscles which all help with their ability to perch. Unique and complex vocal organ.

Question 2

Review the different foot structures of birds to show how unrelated birds evolved similar, but not identical, arrangements of the 4 toes.

Answer 2

Most perching birds have ansiodactyl feet )primitive condition.
-8 different groups (owls, cuckoos, woodpeckers and allies, etc.) have zygodactyl feet. Different working order of these bones in some of the groups show evolution of this trait in different ways.

Question 3

How have DNA studies shed light on the relationships of: a) swallows with different nest construction behaviors; b) Galliformes and Anseriformes; and c) grebes and flamingos?

Answer 3

b