Bio Chap 34

Select the vertebrate taxon or taxa whose origin(s) involved duplication of Hox genes -Gnathostomes -Craniates -The genus Homo

-Gnathostomes -Craniates

Which of the following chordate groups include(s) humans? -Hominins -Amniotes -Gnathostomes

-Hominins -Amniotes -Gnathostomes

Which of the following statements best describes the overall process of descent with modification?

A trait present in an ancestral organism is modified by natural selection over time in descendants of that ancestor. Evolution is a process of descent with modification: Characteristics present in an ancestral organism are altered in its descendants over time as they face different environmental conditions. One result of descent with modification is that related species can have characteristics that have an underlying similarity yet different functions. Descent with modification occurring in different evolutionary lineages may result in species in each of those lineages having characteristics that function similarly yet are not due to common descent as those species have independently adapted to similar environmental conditions.

What is the significance of the evolution of Hox gene clusters during vertebrate evolution?

Duplication of Hox genes made increased morphological complexity possible; As a result of gene duplication, craniates possess two or more sets of Hox genes (lancelets and tunicates have only one). Other important families of genes that produce signaling molecules and transcription factors are also duplicated in craniates. The additional genetic complexity due to duplication of Hox genes may have made it possible for craniates to develop more complex morphologies than those of lancelets and tunicates

Which of the following statements describing hominin evolution is/are correct

Homo sapiens is the only surviving member of a highly branched evolutionary tree of hominin species.

What did the Haikouella, a primitive early chordate fossil, lack that vertebrates have?

a skull; Haikouella lacked a skull, a trait found in vertebrates.

Which of the following chordates is most likely to look the LEAST like other chordates?

adult tunicate An adult tunicate does not have a notochord (or vertebrae), a nerve cord, or a post-anal tail. The only chordate feature it retains is pharyngeal slits.

Listed below are four adaptations of terrestrial vertebrates. Which is a characteristic only of truly terrestrial animals with no need to return to water at any stage of the life cycle?

amniotic eggs

Most members of which of the following groups are most closely associated with a wet or moist environment?

amphibians

The diagnostic feature of Chondrichthyes is _____.

an endoskeleton of calcified cartilage The cartilaginous skeleton of sharks and their relatives is reinforced with calcium.

Jaws evolved _____.

by modification of the skeletal rods that previously supported the anterior pharyngeal gill slits According to a leading hypothesis, this marked a reduction in the number of pharyngeal gill slits and a change in the function of gills from feeding to respiration.

Based on the highlighted (white) branches in the phylogenetic tree shown, which of the following labels refers to a paraphyletic group?

green algae; A monophyletic group consists of an ancestral species and all of its descendants. Examples of monophyletic groups in this phylogenetic tree include red algae, plants, chlorophytes, charophytes, and the supergroup Archaeplastida. In contrast, a paraphyletic group consists of an ancestral species and some, but not all, of its descendants. In this tree, green algae are a paraphyletic group, because they consist of chlorophytes, charophytes, and their common ancestor, but not plants, which are also descended from the same common ancestor.

There are three major groups of mammals, categorized on the basis of their _____.

method of reproduction; Monotremes are egg-laying mammals, marsupials are pouched mammals, and eutherians are placental mammals.

Neural crest cells appear on the edges of the neural tube and spread throughout the embryo, giving rise to all of the following structures except __________.

pharyngeal slits (or clefts) of invertebrate chordates The neural crest is unique to vertebrates and does not exist in earlier chordate lineages, such as invertebrates

Which of the following statements about hominin evolution is correct? As hominins have evolved, _____.

sexual dimorphism was significantly reduced Reduced sexual dimorphism is associated with pair-bonding.

Which of the following is NOT a diagnostic feature of the Chordata?

vertebrae; Lancelets and tunicates are two subgroups of chordates that lack vertebrae. Hagfishes do, too.

In the phylogenetic tree shown, which of the following are shared ancestral characters for members of the turtle-leopard group?

vertebral column; four limbs; A shared ancestral character is a character that is not unique to a particular group, having originated in an ancestor of that group. For members of the turtle-leopard group, the phylogeny shows that a vertebral column, hinged jaws, and four limbs are all shared ancestral characters, having originated before the turtle-leopard group diverged from other lineages shown in the tree. In contrast, a shared derived character is an evolutionary novelty that is unique to a particular group; in the phylogeny shown here, an amnion is a shared derived character for the turtle-leopard group.