biology II - CHAPTER 33: INTRO TO ANIMAL DIVERSITY

TRUE OR FALSE? both traditional and molecular approaches of classification support the theory that the Chordates and the echinoderms share a common ancestor and thus belong to the same clade, the Deuterostomia.

TRUE

TRUE OR FALSE? in segmented animals like earthworms (phylum Annelida), each segment may develop a nearly complete set of adult organ systems.

TRUE

TRUE OR FALSE? locomotion is more efficient in segmented animals because individual segments can move semi-independtly.

TRUE

TRUE OR FALSE? both traditional and molecular approaches of classification support the theory that animals with radial symmetry such as members of the phylum Cnidaria and Bilateral split apart from one another early in the history of animals.

TRUE the branch point between these two groups of animals occurred very early.

TRUE OR FALSE? animals display bilateral symmetry can be divided into no more than one vertical plane at midline, where each half creates a mirror image of the other.

TRUE. bilateral symmetry is well correlated with the ability to move and an anterior consolidation of sensory structures, or cephalization.

TRUE OR FALSE? animals with radial symmetry include the phyla cnidaria and Ctenophora.

TRUE. these two radiate phyla are typically circular or tubular in shape, with a mouth at one end.

reasons why choanoflagellates are thought to be the closest living relatives to animals:

molecular comparisons between choanoflagellates and simple animals are similar. they are similar to the cells of simple animals.

During the Cambrian explosion, the evolution of Hox genes is thought to have assisted rapid speciation because ------- changes in the expression of Hox genes lead to ------- variation among certain important morphological traits.

simple; large

Which characteristics are included in the Lophototrochozoa grouping?

- a crown of tentacles - trochophore larvae

general characteristics within the animal species

- animals have the capacity to move to at some point in their life cycle. - most species undergo sexual reproduction where a small motile sperm unites with a larger egg cell to produce a zygote. - all animals are heterotrophs.

the molecular basis if animal classification focuses on sequence data. characteristics that would apply:

- molecular technique primarily compare the sequences of DNA or RNA to evaluate relatedness. - SSU rRNA is a large molecule that contains a lot of genetic information and is used for classification because it is universally found in all organisms. - new evidence from molecular techniques suggest that the Annelida and the Arthropoda are not as closely related as traditional approaches would indicate.

Invertebrates that shed their skin...

Ecdysozoa

TRUE OR FALSE? positions isolate each segment so each must contract or expand in unison.

FALSE

TRUE OR FALSE? redundancy in segmented animals is not an advantage.

FALSE

TRUE OR FALSE? the traditional approach to animal classification supports the theory that the protostomes are divided into two major groups: the Lophotrochozoa and the Ecdysozoa.

FALSE it was molecular evidence that suggested that the protostomes be divided into two new clades: the Lophotrochozoa and the Ecdysozoa.

TRUE OR FALSE? genetic analyses now suggest that animal groups arose independently from multiple clades.

FALSE evidence suggest that animals arose from one common clade

TRUE OR FALSE? a jellyfish displaying radial symmetry can be divided into no more than three lines of symmetry.

FALSE. jellyfish (phylum cnidaria) display true radial symmetry and are symmetrical along any longitudinal plane passing through the central axis of the body, not just three planes.

TRUE OR FALSE? all non-radiate animals, including the sponges, display bilateral symmetry.

FALSE. small sponges (phylum Porifera) display radial symmetry, but most display asymmetrical symmetry.

Germ layers

ectoderm