Eucarya

A eukaryote is an organism whose cells are organized into complex structures enclosed within membranes. Many living organisms we are familiar with, including all animals, plants, and fungi, are eukaryotes. The defining membrane-bound structure that differentiates eukaryotic cells from other types of cells is the nucleus. Cells without a nucleus are called prokaryotic cells, and […]

The Tree of Life

The phylogenetic tree or evolutionary tree shows the evolutionary relationships among various biological species. In a phylogenetic tree, each node with descendants represents the most recent common ancestor of the descendants. Each node is called a taxonomic unit. Key Concept: All cells come from preexisting cells. Most broadly, scientists classify life into three domains. Humans, […]