Question

A professor begins a lecture on animal phylogeny (as shown in Figure 32.11) by saying, “We are all worms.” In this context, what did she mean?

Short answer

The professor used the phrase “We are all worms” to indicate that human beings (one of the chordate animals) evolved along with worms from a common ancestral organism.

Step-by-step solution

Vertebrates and invertebrates

The organisms of the animal kingdom are grouped under several phyla and classes, but on a broader aspect, these organisms can be classified into vertebrates (animals that comprise a vertebral column in their body) and invertebrates (soft-bodied animals that lack vertebral column).

Human beings- being as worm

Human beings are animals belonging to the chordate group. They are part of class Mammalia and are known for their reasoning and speech production abilities. Another characteristic of human beings is that these chordates exhibit bipedal locomotion.

Phylogeny of animals (worms)

The phylogenetic tree of animals suggests that all the chordate animals (including humans) share a common ancestor with the invertebrate animals of the worm category (such as acoelomate and annelids).

The professor exclaimed: “We are all worms.” as she wanted to convey that humans share common ancestry with worms and, thus, must contain some common features.