The most complex single-celled organism
The dinoflagellate is a very complex grade of protest. Dinoflagellates have a very complex development cycle. A typical dinoflagellate can metamorphize into more than a dozen different developmental stages.
Most stages of a dinoflagellate species are unicellular. However, most of them have one ‘colony forming’ stage. This stage is not precisely like the body of a multicellular organism, but it is in some ways similar to a body. Still, the dinoflagellate is considered unicellular in all stages. The colony is not so specialized to compel scientists to classify it as multicellular.
Each different stage of the dinoflagellate is relatively complex. The organism seems to have a stage that correlates with the form of other protist species. The complexity of the dinoflagellate's genome leads to the complexity of the dinoflagellate's lifestyle. The dinoflagellate turns its genes on and off in response to its environment. Each stage correlates with a network of genes that is part of the dinoflagellate genome. The dinoflagellates of a stage are determined by a network of genes that are expressed while most of the other gene networks are not expressed.
Most of the stages in a dinoflagellate's life can reproduce asexually, forming a clonal colony of dinoflagellates in this stage. This really is not much different from the differentiation of tissue types in a human body. Each one-celled stage of a dinoflagellate's life is more complex than the cell of a particular tissue in the human body. The dinoflagellate has more different types of stages than humans have different tissues.
So one can claim that a clonal colony of dinoflagellates is analogous to a tissue in a mammals body. A clonal colony of dinoflagellates some of which are in different stages of development can be thought of as a multicellular body more complex than any animal body.
Dinoflagellates can chose to be haploid or diploid with respect to karyotype. The haploid stages of dinoflagellate life are analogous to gametes in animals. Each of these ‘gametes’ itself has multiple stages of development. Two haploids can merge to form a zygote analog, usually called a cyst. So the dinoflagellates are even more complex than animals in terms of their sex life
Note that dinoflagellates sexually reproduce only once in their entire lives. Two haploid dinoflagellates fuse to form one diploid cell, which hibernates in the form of a cyst. When the cyst breaks, it asexually reproduces many times into a diploid community of cells. Members of this diploid community transform into any number of stages. However, the haploid cells can also make all sorts of transformations.
Dinoflagellate cells communicate with each other in a large number of ways. However, the chief means for one cell to communicate with another is through light. Many dinoflagellate species have the ability to bioluminesce.
The dinoflagellates use bioluminescence to control the rate of luminescence in a clonal community. So the density of a clonal community stops increasing before overpopulation kills any dinoflagellates in the same family.
So according to most definitions of complexity, a dinoflagellate is MORE COMPLEX than an animal. Yet, the dinoflagellate is unicellular.
The dinoflagellate is a very complex grade of protest. Dinoflagellates have a very complex development cycle. A typical dinoflagellate can metamorphize into more than a dozen different developmental stages.
Most stages of a dinoflagellate species are unicellular. However, most of them have one ‘colony forming’ stage. This stage is not precisely like the body of a multicellular organism, but it is in some ways similar to a body. Still, the dinoflagellate is considered unicellular in all stages. The colony is not so specialized to compel scientists to classify it as multicellular.
Each different stage of the dinoflagellate is relatively complex. The organism seems to have a stage that correlates with the form of other protist species. The complexity of the dinoflagellate's genome leads to the complexity of the dinoflagellate's lifestyle. The dinoflagellate turns its genes on and off in response to its environment. Each stage correlates with a network of genes that is part of the dinoflagellate genome. The dinoflagellates of a stage are determined by a network of genes that are expressed while most of the other gene networks are not expressed.
Most of the stages in a dinoflagellate's life can reproduce asexually, forming a clonal colony of dinoflagellates in this stage. This really is not much different from the differentiation of tissue types in a human body. Each one-celled stage of a dinoflagellate's life is more complex than the cell of a particular tissue in the human body. The dinoflagellate has more different types of stages than humans have different tissues.
So one can claim that a clonal colony of dinoflagellates is analogous to a tissue in a mammals body. A clonal colony of dinoflagellates some of which are in different stages of development can be thought of as a multicellular body more complex than any animal body.
Dinoflagellates can chose to be haploid or diploid with respect to karyotype. The haploid stages of dinoflagellate life are analogous to gametes in animals. Each of these ‘gametes’ itself has multiple stages of development. Two haploids can merge to form a zygote analog, usually called a cyst. So the dinoflagellates are even more complex than animals in terms of their sex life
Note that dinoflagellates sexually reproduce only once in their entire lives. Two haploid dinoflagellates fuse to form one diploid cell, which hibernates in the form of a cyst. When the cyst breaks, it asexually reproduces many times into a diploid community of cells. Members of this diploid community transform into any number of stages. However, the haploid cells can also make all sorts of transformations.
Dinoflagellate cells communicate with each other in a large number of ways. However, the chief means for one cell to communicate with another is through light. Many dinoflagellate species have the ability to bioluminesce.
The dinoflagellates use bioluminescence to control the rate of luminescence in a clonal community. So the density of a clonal community stops increasing before overpopulation kills any dinoflagellates in the same family.
So according to most definitions of complexity, a dinoflagellate is MORE COMPLEX than an animal. Yet, the dinoflagellate is unicellular.
