Exam 32: An Overview of Animal Diversity

Use the following two diagrams (A and B) to answer the questions below. A: Morphological phylogeny. B: Molecular phylogeny. -What is true of the deuterostomes in the molecular phylogeny (B)that is not true in the traditional phylogeny (A)?

The figure above shows a chart of the animal kingdom set up as a modified phylogenetic tree. Use the diagram to answer the following questions. -Which two groups have members that undergo ecdysis?

Use the following information to answer the questions below. The most recently discovered phylum in the animal kingdom (1995) is the phylum Cycliophora. It includes three species of tiny organisms that live in large numbers on the outsides of the mouthparts and appendages of lobsters. The feeding stage permanently attaches to the lobster via an adhesive disk, and collects scraps of food from its host's feeding by capturing the scraps in a current created by a ring of cilia. The body is sac-like and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans are eucoelomate, do not moult (though their host does), and their embryos undergo spiral cleavage. -Using similarities in embryonic development, body symmetry, and other anatomical features to assign an organism to a clade involves 1. cladistics based on body plan. 2. molecular-based phylogeny. 3. morphology-based phylogeny.

What is the probable sequence in which the following clades of animals originated, from earliest to most recent? 1. tetrapods 2. vertebrates 3. deuterostomes 4. amniotes 5. bilaterians

Arthropods invaded land about 100 million years before vertebrates did so. This most clearly implies that

Use the following information to answer the questions below. The most recently discovered phylum in the animal kingdom (1995) is the phylum Cycliophora. It includes three species of tiny organisms that live in large numbers on the outsides of the mouthparts and appendages of lobsters. The feeding stage permanently attaches to the lobster via an adhesive disk, and collects scraps of food from its host's feeding by capturing the scraps in a current created by a ring of cilia. The body is sac-like and has a U-shaped intestine that brings the anus close to the mouth. Cycliophorans are eucoelomate, do not moult (though their host does), and their embryos undergo spiral cleavage. -If harbouring large populations of cycliophorans neither helps nor harms their lobster hosts, then cycliophorans can be properly considered to be 1. parasites. 2. mutualists. 3. commensals. 4. symbionts. 5. endosymbionts.

The Hox genes came to regulate each of the following in what sequence, from earliest to most recent? 1. identity and position of paired appendages in protostome embryos 2. anterior-posterior orientation of segments in protostome embryos 3. positioning of tentacles in cnidarians 4. anterior-posterior orientation in vertebrate embryos

You have before you a living organism, which you examine carefully. Which of the following should convince you that the organism is acoelomate?

A researcher is trying to construct a molecular-based phylogeny of the entire animal kingdom. Assuming that none of the following genes is absolutely conserved, which of the following would be the best choice on which to base the phylogeny?

Use the following information to answer the questions below. Trichoplax adhaerens (Tp) is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. They move using cilia, and any "edge" can lead. Tp feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. Tp sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage. -In its native environment, a Tp cell neither gains nor loses water. What should one expect to occur when Tp is placed into fresh water?

What is true of the clade Ecdysozoa?

Use the following table to answer the questions below. Proposed Number of Hox Genes in Various Extant and Extinct Animals -All things being equal, which of these is the most parsimonious explanation for the change in the number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in the table?

Use the following information to answer the questions below. Trichoplax adhaerens (Tp) is the only living species in the phylum Placozoa. Individuals are about 1 mm wide and only 27 μm high, are irregularly shaped, and consist of a total of about 2000 cells, which are diploid (2n = 12). There are four types of cells, none of which are nerve or muscle cells, and none of which have cell walls. They move using cilia, and any "edge" can lead. Tp feeds on marine microbes, mostly unicellular green algae, by crawling atop the algae and trapping it between its ventral surface and the substrate. Enzymes are then secreted onto the algae, and the resulting nutrients are absorbed. Tp sperm cells have never been observed, nor have embryos past the 64-cell (blastula) stage. -In how many of the following ways is Tp unlike the typical animal? 1. Tp is multicellular. 2. Tp lacks muscle and nerve cells. 3. Tp has cilia. 4. Tp has a different place where digestion of food occurs. 5. Tp lacks cell walls.

If the current molecular evidence regarding animal origins is well-substantiated in the future, then what will be true of any contrary evidence regarding the origin of animals derived from the fossil record?

According to the evidence collected so far, the animal kingdom is

Which of the following characteristics generally applies to protostome development?

Among the characteristics unique to animals is

The blastopore denotes the presence of an endoderm-lined cavity in the developing embryo, a cavity that is known as the

The blastopore is a structure that first becomes evident during

Fossil evidence indicates that the following events occurred in what sequence, from earliest to most recent? 1. Protostomes invade terrestrial environments. 2. Cambrian explosion occurs. 3. Deuterostomes invade terrestrial environments. 4. Vertebrates become top predators in the seas.