Identify the pattern of embryonic development shown in each drawing below and name the phylum (or phyla) that exhibit this pattern.

Verified step by step guidance

1. Observe the three drawings labeled a, b, and c. Each drawing represents a different stage of embryonic development.
2. In drawing a, identify the two primary germ layers: the ectoderm (outer layer) and the endoderm (inner layer).
3. In drawing b, note the formation of the future mouth. This indicates the development of a protostome, where the mouth forms before the anus.
4. In drawing c, observe the formation of the future anus. This indicates the development of a deuterostome, where the anus forms before the mouth.
5. Identify the phyla: Protostomes include phyla such as Arthropoda, Mollusca, and Annelida. Deuterostomes include phyla such as Chordata and Echinodermata.

Key Concepts

Germ Layers

Germ layers are the primary layers of cells in the early embryo that develop into all tissues and organs. The ectoderm forms the outer layer, giving rise to the skin and nervous system, while the endoderm becomes the inner layer, developing into the digestive tract and associated organs. Understanding these layers is crucial for identifying embryonic development patterns.

Embryonic Development Patterns

Embryonic development patterns refer to the specific arrangements and transformations of germ layers during the early stages of an organism's development. Two primary patterns are protostome and deuterostome development, distinguished by the fate of the blastopore, which becomes the mouth in protostomes and the anus in deuterostomes. Recognizing these patterns helps classify organisms into their respective phyla.

Phyla Classification

Phyla classification is a taxonomic rank used to group organisms based on shared characteristics and evolutionary history. In the context of embryonic development, organisms are often classified as either protostomes (e.g., arthropods, mollusks) or deuterostomes (e.g., chordates, echinoderms) based on their developmental patterns. This classification is essential for understanding the diversity of life and evolutionary relationships.