Question

If you were studying the evolution of animal-specific cell-to-cell signaling systems, from which of the following would you choose representative species to observe? a. Rhodophyta b. Excavata c. Choanomonada d. Radiolaria e. Chlorophyta

Short answer

c. Choanomonada

Step-by-step solution

Analyze the Choices

Go through all the option to understand what they represent. Rhodophyta are red algae and belong to the plant kingdom, Excavata are a major group of unicellular organisms including both free-living and parasitic species, Radiolaria are protozoa and belong to the supergroup Rhizaria, and Chlorophyta are green algae, also from the plant kingdom.

Determine the Best Choice

Evaluate each option in the context of the provided prompt. Here, the question pertains to evolution of 'animal-specific' cell-to-cell signalling so we should choose an organism closely related to animals.

Choose the Correct Option

Choanomonada, also known as Choanoflagellates, are a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals. They are an ideal representative species to pick for observing evolution of animal-specific cell-to-cell signalling systems as their relationship to metazoans has been deeply studied, and they provide a crucial understanding of the origin of animals.

Key concepts

Choanoflagellates

Choanoflagellates are fascinating organisms that play a key role in understanding the evolution of animals. These are free-living unicellular and colonial organisms that use a flagellum to move. What makes choanoflagellates particularly special is their close relationship to animals.

• They are considered the closest living relatives of the Animal Kingdom.
• Studying choanoflagellates helps scientists learn about the traits that might have been present in the earliest animals.
Chaoanoflagellates have a structure called a "collar" made of microvilli that surrounds their flagellum. This structure helps them capture food particles.

Interestingly, the genes found in choanoflagellates are remarkably similar to those in animals, especially those involved in cell-to-cell signaling. This similarity allows scientists to trace the evolutionary steps from single-celled organisms to complex multicellular animals.

Cell-to-Cell Signaling

Cell-to-cell signaling is an essential process in multicellular organisms, allowing cells to communicate and coordinate their activities. This communication is crucial for various functions, including development, immune responses, and maintaining homeostasis.

In the context of evolution, one of the key questions has been how animals developed complex systems of cell signaling. Choanoflagellates have provided vital clues.
• They possess many of the same proteins involved in signaling that are found in animals.
• These proteins include those involved in communication pathways that influence cell division, differentiation, and adhesion.
By studying choanoflagellates, researchers can infer how early animals might have developed these sophisticated communication systems. This knowledge helps explain how multicellularity could have arisen from simpler organisms.

Animal Kingdom

The Animal Kingdom is a diverse group of multicellular organisms that exhibit a wide range of forms and functions. Despite their diversity, all animals share certain characteristics, such as being eukaryotic, possessing specialized tissues, and having the ability to move at some point in their life cycle.

The evolution of this kingdom is a subject of immense interest to scientists because it involves understanding the transition from simple unicellular organisms to complex multicellular forms.
• Animals are believed to have evolved around 600 million years ago during the Precambrian era.
• This evolution involved significant changes such as the development of specialized cell types and complex body plans.
Choanoflagellates provide a living window into the evolutionary past, offering insights into what the common ancestor of all animals might have looked like. Their study sheds light on key innovations such as the development of cell-to-cell signaling and adhesion proteins that are essential for multicellularity.

Evolutionary Biology

Evolutionary Biology is the study of the origins and changes in the diversity of life over time. It involves understanding how species evolve via mechanisms like natural selection, genetic drift, mutations, and gene flow.

In the context of animals, evolutionary biology seeks to elucidate how complex life forms have arisen from simpler ones. One of the fascinating aspects of this field is studying the transition from unicellular organisms, like choanoflagellates, to the complex life forms seen in the Animal Kingdom.
• Through comparative studies, researchers use fossils, morphological data, and genetic information to reconstruct evolutionary histories.
• A critical aspect of this research is understanding the molecular foundation of development and how novel traits evolve.
• These studies help explain the massive diversity seen in living organisms today.
Evolutionary biology is instrumental in unraveling the mysteries of how cell-to-cell signaling systems, like those observed in choanoflagellates, might have laid the groundwork for complex multicellular life.