Phyla Closest to Chordates
The question asks to identify the phylum most closely related to Chordates from the given options. Evolutionary relationships are often determined by shared developmental patterns and genetic similarities.
Deuterostome Connection
Chordates belong to the superphylum Deuterostomia. Within this group, organisms share key embryonic features. Phylogenetic analyses show that the phylum Echinodermata (which includes starfish, sea urchins, and sea cucumbers) is the closest relative to chordates.
- Both chordates and echinoderms are deuterostomes.
- Key deuterostome features include radial cleavage and the anus forming from the blastopore.
Protostome Contrasts
The remaining options belong to the superphylum Protostomia:
- Annelida (segmented worms)
- Arthropoda (insects, crustaceans, etc.)
- Mollusca (snails, squids, etc.)
Protostomes have different developmental patterns (e.g., spiral cleavage, mouth forming from the blastopore). Since Echinodermata shares the deuterostome classification with Chordata, it is considered the most closely related phylum among the choices.
Important Questions from Phylogenetic trees
- Newts produce tetrodotoxin (TTX), a poison that targets sodium ion channels, for defense against their predators, garter snakes. Several species of garter snakes are resistant to newt TTX due to specific known amino acid substitutions in garter snake sodium channels. Which one of the following is best-suited to identify whether this adaptation in garter snakes has a single origin or multiple independent origins?
A phylogenetic tree representing the evolutionary relationship between various vertebrates is shown below.
Given this tree topology, which one or more of the following statements is/are correct?A phylogenetic tree for the evolution of two pigmentation traits in species of fish is shown for clades X, Y and Z. Genes A and/or B, if mutated, can cause dark pigmentation in the body.
Which one or more of the following statements is/are correct?- Whales and dolphins are hypothesized to have evolved along the northern shore of the Tethys Sea, prior to the Indian plate's collision with the Eurasian plate. To which one of the following animals are these aquatic mammals most closely related?
In the phylogenetic trees shown, the tips represent different species of geckos(labeled A to E) and the areas to which they belong. Which one of these is most consistent with the hypothesis that the geckos colonized the Western Ghats from Northeast India through the Eastern Ghats?
