Exam 17: The Evolution of Animals

At a natural history museum, you see a skeleton with the following characteristics: four long, slender finger bones and a smaller opposable thumb bone, and larger feet with long toes. In what type of environment would you expect this organism to have lived?

Scenario Several studies involving molecular analyses of Comb jellies, also known as sea gooseberries, cast doubt on the theory that sponges are the oldest animal phylum. Reported results of the studies suggested that Comb jellies, more complex animals having muscles and a nervous system, may actually be the true, first phylum of animals that diverged from a metazoan common ancestor. However, in 2015, a team of scientists re-analyzed the genetic data in the Comb jellies research with more specialized methods, and they determined that sponges were indeed the oldest animal phylum. -Suppose that the re-analysis of the genetic data confirmed that Combjellies are the oldest animal phylum. It is therefore likely that their complex traits, such as organ systems, would probably have been present in the common ancestor as well. Therefore, any organisms that would have diverged from the common ancestor after the comb jellies, such as sponges, should likely have similar organ systems. What is the best hypothesis for why sponges do not have a nervous system?

The first hominid species to spread beyond Africa was ________.

-The evolutionary tree indicates that humans and orangutans shared a common ancestor approximately ________.

Almost every element of bird anatomy is modified for what?

________ are characterized body tissues, radial symmetry, and tentacles with stinging cells.

There are more species of ________ than of any other type of animal.

Radial symmetry is seen in a ________.

________ are the most diverse group of arthropods.

All ________ exhibit the arthropod characteristic of multiple pairs of specialized appendages.

A characteristic of arthropods that has allowed for their great success is the presence of ________.

Tunicates are examples of ________.

-The phylogenetic tree indicates that annelids are most closely related to ________.

-The phylogenetic tree indicates that ________ demonstrate the most advanced body plan in reference to the presence of tissues and bilateral symmetry.

How do New World monkeys differ from Old World monkeys?

While on an archaeology expedition, you unearth a skeleton with the following characteristics: four long, slender finger bones and a smaller opposable thumb bone, long arm bones, fingernails, and eye sockets close together on a skull. What type of organism do you suspect you may have found?

Which mode of nutrition characteristic distinguishes animals from other eukaryotes?

A(n)________ is an example of a chordate that is not a vertebrate.

You discover an organism that has scaly skin and is aquatic but returns to the land to reproduce. What else would you expect to find in this organism?

-The evolutionary indicates that if a new anthropoid specimen was discovered and estimated to be approximately 42 million years old, it would be characterized as ________.