From simple beginnings, animals have come a long way. Even before the first humans appear on earth, evidence has shown that animals have been capable of evolving over millions of years. In fact, scientists have shown that animal-like eggs evolved far before the first creatures appear in the fossil record. Under a new milestone study, cells can rapidly evolve, developing specific roles under a wide spectrum of environmental conditions than has so far been accepted. This study published in Nature Communications shows how quickly and dramatically animal evolution occurs.
The study looked at the evolution of animal cells across the spectrum of habitats. All animal groups – both chordate and unicellular – showed widespread evolution within their genomes, revealing multiple cellular mechanisms interacting with one another. Surprisingly, the study did not consider the three animal taxa, the protozoa, which are a class of unicellular algae, and cilia, which are projections of the arthropods and certain insects. These three taxa collectively encompass all vertebrates, and their divergence from other animals via convergent evolution is the basis for the study’s conclusions.
The researchers began by designing a two-dimensional model of the early Earth with an outline representing the major evolutionary transitions. They then examined four representative animal groups to chart their evolution and compare them with each other and with the eukaryotic taxa. Surprisingly, all the branches showed convergent evolution – that is, they were derived from a common ancestor of all animals. This study provides evidence for the importance of animal cells in the development of multicellular eukaryotes. It also demonstrates that these organisms may have a role in controlling the Earth’s climate.
The study looked specifically at two animal species: Bacteria and Protista. Through fossils, we can recognize the relationships among these animals and some other groups of animals and invertebrates. What was surprising was that the analysis showed that Bacteria had more complex cell structures than did the invertebrates, indicating that they may be using something that Nature has provided instead of making their own structure. The main article discusses the major results from this study, but briefly mention the less obvious relationships. Specifically, we look at how Bacteria and the other animals and invertebrates make up the Earth’s watery surface, how the latter are related to animal and plant cells, and how plants control the weather. We also consider the possibility that animal species may utilize Earth’s magnetic field to create food, regulate body temperature, and even protect themselves from predators.
Studying the fossil record and inferring relationships between animals and their fossilized counterparts goes a long way toward answering questions about the relationships between animals and their fossilized relatives. Interestingly, this study confirms a long-standing theory about how insects arose. The study found that all vertebrates that lived earlier than the Triassic were composed of nothing more than simple unicellular organisms, while the later animals (which gave rise to modern insects) were composed of multiple cell layers. The paper also indicates that there is a relationship between dinosaurs and the animals known as Multicellular (Mammalia). This is because dinosaurs are hypothesized to have evolved from a group of mammals that are now classified as Mollusks.
Insects and the Earth are closely related. Many types of insects secrete chemical compounds that are vital for plant growth and development. Many kinds of animals are also specialists in dealing with predators. They often have highly developed defensive mechanisms, which allow them to avoid being eaten by other animals and sometimes survive an attack. Some examples of these include the fact that bees secrete venom to defend themselves against other bees and other insects, certain forms of birds have become specialized to trap other birds, and many amphibians (such as turtles and chameleons) secrete certain chemicals that either attack or flee prey.