More Lessons for Biology
A series of free High School Biology Video Lessons.
In Biology, classification is the way to organize living things based on evolutionary relationships. Traditionally, we organize species into the standard hierarchy of kingdom, phylum, class, order, family and genus.
An overview of Biology classification systems.
Cladistics is the method of classifying organisms into groups called clades. Clades consist of an ancestor organism and all of it's decedents and one branch is the tree of life. Cladograms are diagrams that show relationships within a clade.
This video shows you how to construct a cladogram from a group of organisms using shared characteristics. It also discusses the process of parsimony in cladogram construction. It then explains how modern cladograms are constructed and walks through a cladogram of primates.
A phylogenetic tree is a branching diagram that shows evolutionary relationships. These trees, often compared to family trees, are constructed using a variety of evidence generally using DNA. In phylogenetic trees, sometimes the lengths of the branches represent time since a group split from each other.
Explanation of the Phylogenetic Tree.
This video discusses the specifics of phylogenetics. The evolutionary relationships of organisms are discovered through both morphological and molecular data. A specific type of phylogenetic tree, the cladogram, is also covered.
Like the Animal Kingdom, the Plant Kingdom is also a major part of the Linnaean system of classification that includes organisms like trees, bushes and grasses. The plants in this kingdom can be called autotrophs because they perform photosynthesis to provide food for themselves. These organisms also provide oxygen for humans and animals to survive.
Description of the plant kingdom.
Tis video surveys the Kingdom Plantae. It begins with a brief description of the phylogeny of land plants. It then describes the defining characteristics of plants, including cell walls, embryophytes, alternation of generation and photosynthesis. It briefly describes the sporophyte and the gametophyte. It finishes with brief discussion of plant evolution and includes major divisions, like bryophytes, ferns, gymnosperms, and angiosperms.
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