Germ Layers and Organisms Flashcard

Front

Which germ layer forms the outer layer, including skin and nervous system?

Back

Ectoderm

Answer explanation

The ectoderm is the outermost germ layer in embryonic development, giving rise to the skin and the nervous system. Therefore, it is the correct answer for the layer that forms the outer structures.

Front

What does the endoderm form?

Back

Digestive tract and respiratory system

Answer explanation

The endoderm is one of the three primary germ layers in embryonic development. It primarily forms the digestive tract and respiratory system, making 'Digestive tract and respiratory system' the correct choice.

Front

Which germ layer is responsible for forming muscles and bones?

Back

Mesoderm

Answer explanation

The mesoderm is the germ layer responsible for forming muscles and bones, as it gives rise to the skeletal, muscular, and circulatory systems, among other structures. The ectoderm and endoderm form other tissues.

Front

How many germ layers are present in diploblastic organisms?

Back

2

Answer explanation

Diploblastic organisms have two germ layers: the ectoderm and the endoderm. This is in contrast to triploblastic organisms, which have a third layer called the mesoderm. Therefore, the correct answer is 2.

Front

Example of a diploblastic organism: Mollusks, Arthropods, Cnidarians, Vertebrates

Back

Cnidarians

Answer explanation

Cnidarians, such as jellyfish and corals, are diploblastic organisms, meaning they have two germ layers: ectoderm and endoderm. In contrast, mollusks, arthropods, and vertebrates are triploblastic, having three germ layers.

Front

What type of symmetry do diploblastic organisms exhibit?

Back

Radial

Answer explanation

Diploblastic organisms, such as cnidarians, exhibit radial symmetry, allowing them to be divided into similar halves around a central axis. This symmetry is advantageous for their lifestyle, facilitating interaction with the environment from all directions.

Front

Which body plan is associated with triploblastic organisms?

Back

Complex

Answer explanation

Triploblastic organisms have three germ layers: ectoderm, mesoderm, and endoderm. This complexity allows for more advanced body structures and systems, making the 'Complex' body plan the correct association.

Front

What is a coelom?

Back

A fluid-filled body cavity

Answer explanation

A coelom is defined as a fluid-filled body cavity found in many animals, providing space for organs and allowing for greater complexity in body structure. This distinguishes it from other options like germ layers or symmetry.

Front

What type of symmetry do triploblastic organisms typically have?

Back

Bilateral

Answer explanation

Triploblastic organisms, which have three germ layers, typically exhibit bilateral symmetry. This means their body can be divided into two mirror-image halves, a characteristic that aids in directional movement and organization.

Front

Which of the following is an example of a triploblastic organism? Coral, Jellies, Mollusks, Anemones

Back

Mollusks

Answer explanation

Mollusks are triploblastic organisms, meaning they have three germ layers: ectoderm, mesoderm, and endoderm. In contrast, corals, jellies, and anemones are diploblastic, having only two germ layers.