Eukaryotes belong to the domain Eukaryota or Eukarya.Their name comes from the Greek εὖ (eu, "well" or "true") and κάρυον (karyon, "nut" or "kernel"). According to various archeological evidences, eukaryotic cells have started to exist more than 0.6 billion years ago . Where Did Eukaryotes Come From? Eukaryotes are more complex and have many more parts than prokaryotes. Up until now, their evolution is viewed by many as one of the most unusual events in biological history . The new eToL results from the widespread application of phylogenomics and numerous discoveries of major lineages of eukaryotes, mostly free-living heterotrophic protists. Living things have evolved into three large clusters of closely related organisms, called "domains": Archaea, Bacteria, and Eukaryota.
Our own eukaryotic cells protect DNA in chromosomes with a nuclear membrane, make ATP with mitochondria, move with flagella (in the case of sperm cells), and feed on cells which make our food with chloroplasts. In eukaryotes, mitochondria energetically support the nuclear genome; this may have enabled the evolution of complex traits. In humans, for example, eye colour is an inherited characteristic and an individual might inherit the "brown-eye trait" from one of their parents. Archaea and Bacteria are small, relatively simple cells surrounded by a membrane and a cell wall, with a circular strand of DNA containing their genes. Our own eukaryotic cells protect DNA in chromosomes with a nuclear membrane, make ATP with mitochondria, move with flagella (in the case of sperm cells), and feed on cells which make our food with chloroplasts.All multicellular organisms and the unicellular Protists share this cellular intricacy. For 15 years, the eukaryote Tree of Life (eToL) has been divided into five to eight major groupings, known as ‘supergroups’. All multicellular organisms and the unicellular Protists share this cellular intricacy. Evolution of Eukaryotes. As life on Earth started to undergo evolution and become more complex, the simpler type of cell called a prokaryote underwent several changes over a long period of time to become eukaryotic cells. However, the tree has been profoundly rearranged during this time. The origin of eukaryotes is a fundamental, forbidding evolutionary puzzle. The second broad theme focuses on specific aspects of cells, genomes, or evolution that are unique or uniquely well developed in eukaryotes. The chromatin material in prokaryotes lie in the cytoplasm while in eukaryotes it is present in the nucleus. Evolution in organisms occurs through changes in heritable traits—the inherited characteristics of an organism. The Evolution of the Eukaryotes As in the prokaryotic world, one can see from this schematic tree of the eukaryotes (below), that the majority of eukaryotic life is, in fact, microbial (protists). From prokaryotes to eukaryotes. Fossil records indicate that eukaryotes evolved from prokaryotes somewhere between 1.5 to 2 billion years ago. Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomal DNA. It took several mutations and surviving natural selection for eukaryotes to evolve and become prevalent. All multicellular organisms and the unicellular Protists share this cellular intricacy. Prokaryotes were the only form of life on Earth for millions of years until more complicated eukaryotic cells came into being through the process of evolution.