<P> Multicellularity has evolved independently at least 46 times , including in some prokaryotes , like cyanobacteria , myxobacteria , actinomycetes , Magnetoglobus multicellularis or Methanosarcina . However , complex multicellular organisms evolved only in six eukaryotic groups : animals , fungi , brown algae , red algae , green algae , and land plants . It evolved repeatedly for Chloroplastida ( green algae and land plants ) , once or twice for animals , once for brown algae , three times in the fungi ( chytrids , ascomycetes and basidiomycetes ) and perhaps several times for slime molds and red algae . The first evidence of multicellularity is from cyanobacteria - like organisms that lived 3 -- 3.5 billion years ago . To reproduce , true multicellular organisms must solve the problem of regenerating a whole organism from germ cells ( i.e. sperm and egg cells ) , an issue that is studied in evolutionary developmental biology . Animals have evolved a considerable diversity of cell types in a multicellular body ( 100 -- 150 different cell types ) , compared with 10 -- 20 in plants and fungi . </P>
<P> Multicellularity has evolved independently at least 46 times , including in some prokaryotes , like cyanobacteria , myxobacteria , actinomycetes , Magnetoglobus multicellularis or Methanosarcina . However , complex multicellular organisms evolved only in six eukaryotic groups : animals , fungi , brown algae , red algae , green algae , and land plants . It evolved repeatedly for Chloroplastida ( green algae and land plants ) , once or twice for animals , once for brown algae , three times in the fungi ( chytrids , ascomycetes and basidiomycetes ) and perhaps several times for slime molds and red algae . The first evidence of multicellularity is from cyanobacteria - like organisms that lived 3 -- 3.5 billion years ago . To reproduce , true multicellular organisms must solve the problem of regenerating a whole organism from germ cells ( i.e. sperm and egg cells ) , an issue that is studied in evolutionary developmental biology . Animals have evolved a considerable diversity of cell types in a multicellular body ( 100 -- 150 different cell types ) , compared with 10 -- 20 in plants and fungi . </P>
when did the first true multi-cellular organisms with true tissues evolve
when did the first true multi-cellular organisms with true tissues evolve
3 -- 3.5 billion years ago
3 -- 3.5 billion years ago