Exam 27: The Rise of Animal Diversity

Cycliophorans have two types of larvae.One type of larva is produced when the digestive system of a female is impregnated by a male.The digestive system then collapses and develops into a larva,which swims away in search of a new host after the surrounding female dies.Which is the embryonic tissue that is apparently most important in forming this type of larva?

Which of the following belong to the lobe-fin clade?

Evidence of which structure or characteristic would be most surprising to find among fossils of the Ediacaran fauna?

The decline of cyanobacteria in the early Cambrian oceans was most likely related to

Which of these characteristics added most to vertebrate success in relatively dry environments?

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

A: Morphological phylogeny. B: Molecular phylogeny. -Which of the following is a point of conflict between the phylogenetic analyses presented in these two figures?

The earliest known mineralized structures in vertebrates are associated with which function?

Jaws first occurred in which extant group of fishes?

The feeding mode of the extinct conodonts was

Please use the following information to answer the questions below. Placozoan evolutionary relationships to other animals are currently unclear,and different phylogenies can be created,depending on the characters used to infer relatedness.Placozoans are multicellular invertebrates with a simple structure of only two tissue layers and only four cell types.They have the smallest amount of DNA measured in any animal.In comparison,sponges have no tissues but about 20 cell types.One species of placozoans,Tp (Trichoplax adhaerens),produces a neuropeptide almost identical to one found in cnidarians.The genome of Tp,although the smallest of any known animal,shares many features of complex eumetazoan (even human!)genomes.The next three questions refer to the phylogenetic trees that follow.In the trees,the outgroup is a taxon that is outside the group of interest;members of the group of interest are more closely related to one another than to the outgroup. -Which tree(s)has (have)been created by emphasizing genomic features of placozoans?

Which of the following was probably the least important factor in bringing about the Cambrian explosion?

Which extant chordates are postulated to be most like the earliest chordates in physical appearance?

Internal fertilization,leathery amniotic eggs,and skin that resists drying are characteristics of which extant vertebrate group?

The last common ancestor of all bilaterians is thought to have had four Hox genes (genes that regulate development of posterior-anterior axes and body segments).Most extant cnidarians have two Hox genes,except Nematostella,which has three Hox genes.On the basis of these observations,some have proposed that the ancestral cnidarians were originally bilateral and,in stages,lost Hox genes from their genomes.If true,this would mean that

Which of the following is unique to animals?

If a multicellular animal lacks true tissues,then it can properly be included among the

The flagella of choanocyte cells in a sponge are most similar in basic function to

Which group's members have had both lungs and gills during their adult lives?

If a physoclistous fish removes gas from its swim bladder,this fish's density cannot actually change until that gas arrives at the