Question

Explain what is represented by the red-colored portion of the branch leading to animals. (See Figure 26.5, “Visualizing Phylogenetic Relationships,” to review phylogenetic tree diagrams.)

Short answer

The red-colored region in the eukaryotic phylogeny of fungi and other animals represents the common ancestor of all animals that existed between a time range of 1 billion years ago (1 bya) and 770 million years ago (770 mya).

The most recent ancestral organism shared between the animal group and choanoflagellates represents an organism of the red-colored portion.

Step-by-step solution

Evolution

In biology, the process or phenomenon which provides an explanation of diversity in life forms (both in extinct and extant organisms) is denoted by the term evolution. The study of evolution incorporates fossil study (exhibits structural diversity) and genomic comparison (gives an idea of the closest organism).

Phylogenetic tree

A phylogenetic tree is defined as the branched diagram that provides an idea of biological diversification over the ages. In the phylogenetic tree, the terminal ends of the branches (leaves) depict the diversified group/organism, and the branched line represents the common ancestral group of the diverse forms.

Explanation for the red-colored portion

The phylogenetic tree of eukaryotic organisms depicted above shows the diversification of fungi and animals. In this phylogeny, the red-colored segment is a branch region that relates to the ancestral organisms common to all the groups of animals.

This organism lived between 1 bya and 770 mya; it had more resemblance to the animals, yet it was not classified as an animal. The most recent organism, which served as a common ancestor for the choanoflagellates and animal groups, exemplifies an organism of that red-colored region.