Life on this earth simply did not start out with animals. All the life on earth started from the primordial ooze where inorganic molecules produced organic molecules, organic molecules formed bigger molecules, and, eventually organic molecules hang together inside membranes. This leads to cell-like structures and then cells. Simpler cells lead to more complex cells. Eventually, and it did take a while, we get the cells that make up animals.
All animals and plants are classified as multicellular eukaryotes: their bodies are made up of large numbers of cells, and microscopic inspection of these cells reveals that they contain a nucleus and a number of other organelles. Compared to prokaryotic organisms such as bacteria, plants and animals have a relatively recent evolutionary origin. DNA evidence suggests that the first eukaryotes evolved from prokaryotes, between 2500 and 1000 million years ago. That is, eukaryotes as a taxon date from the Proterozoic Era, the final Era of the Precambrian. Fossils of both simple unicellular and more complex multicellular organisms are found in abundance in rocks from this period of time. In fact, the name "Proterozoic" means "early life".
Plants and animals both owe their origins to endosymbiosis, a process where one cell ingests another, but for some reason then fails to digest it. The evidence for this lies in the way their cells function. Both plant and animal rely on structures called mitochondria to release energy in their cells, using aerobic respiration to produce the energy-carrying molecule ATP. There is considerable evidence that mitochondria evolved from free-living aerobic bacteria: they are the size of bacterial cells; they divide independently of the cell by binary fission; they have their own genome in the form of a single circular DNA molecule; their ribosomes are more similar to those of bacteria than to the ribosomes found in the eukaryote cell's cytoplasm; and like chloroplasts they are enclosed by a double membrane as would be expected if they derived from bacterial cells engulfed by another cell.
Like the plants, animals evolved in the sea. And that is where they remained for at least 600 million years. This is because, in the absence of a protective ozone layer, the land was bathed in lethal levels of UV radiation. Once photosynthesis had raised atmospheric oxygen levels high enough, the ozone layer formed, meaning that it was then possible for living things to venture onto the land.
The oldest fossil evidence of multicellular animals, or metazoans, is burrows that appear to have been made by smooth, wormlike organisms. Such trace fossils have been found in rocks from China, Canada, and India, but they tell us little about the animals that made them apart from their basic shape.
International Conference on Synthetic Biology, September 28-30, 2015 (Houston, USA); 6th World Congress on Biotechnology, October 05-07, 2015 (New Delhi, India); 3rd International Conference on Genomics & Pharmacogenomics, September 21-23, 2015 (San Antonio, USA); World Bio Summit & Expo, November 02-04, 2015 (Dubai, UAE); International Conference on Genetic Counselling And Genomic Medicine, August 11-12, 2016 (Birmingham, UK); Cell Symposia: Stem Cell Epigenetics 20-22 September 2015 (Barcelona, Spain); EMBO Conference The DNA damage response in cell physiology and disease 5-9 October 2015 (Cape Sounio, Greece); EMBO Conference Nuclear structure and dynamics 7-11 October 2015 (L'Isle-sur-la-Sorgue, France); CSH Asia Mitochondria 12-16 October 2015 (Cold Spring Harbour, New York); ABCAM Chromatin Structure and Function 16-19 November 2015 (Grand Cayman Island).
- Evolution of vertebrates & invertebrates
- Development of multicellular organisums
- Eukaryotes and Prokaryotes
- Modern mammal groups
Related Conference of Animal Evolution
12th International Conference & Exhibition on Tissue Preservation, Life care and Biobanking (B2B & Networking)
Animal Evolution Conference Speakers
- Animal Evolution
- Chromosomal Evolution
- DNA & Protein Substitution
- Driving forces of Evolution
- Genome Architecture
- Genome Evolution
- Molecular Evolution
- Molecular Genetics
- Molecular Oncology
- Molecular Phylogenetics
- Nucleic acid Evolution
- Plant Molecular Evolution
- Protein Evolution
- Role of ribosome and mitochondria
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