Classification and Phylogeny
Systematics is the science of the classification and reconstruction of phylogeny, it means that is responsible for reconstructing the origin and diversification of a taxon (unit that we want to classify, such as a species, a family or an order).
On the other hand, taxonomy is the study of the principles of scientific classification, the order and the name of organisms.
In other words, while systematics is responsible for creating systems of classification, which are represented by trees, taxonomy establishes the rules and methods to identify, name and classify each species in the different taxonomic categories based on systematics.
Taxonomy: Interpreting Graphics
Classification - reinforcement exercise
Dichotomous Keys: Norns | Smilies | Pamishans
Taxonomy Project - create a taxonomy scheme for aliens
NGSS Link
Inheritance and Variation of Traits help students in pursuing an answer to the question: “How are the characteristics from one generation related to the previous generation?” High school students demonstrate understanding of the relationship of DNA and chromosomes in the processes of cellular division that pass traits from one generation to the next. Students can determine why individuals of the same species vary in how they look, function, and behave. Students can develop conceptual models for the role of DNA in the unity of life on Earth and use statistical models to explain the importance of variation within populations for the survival and evolution of species. Ethical issues related to genetic modification of organisms and the nature of science can be described. Students can explain the mechanisms of genetic inheritance and describe the environmental and genetic causes of gene mutation and the alteration of gene expression. Crosscutting concepts of structure and function, patterns, and cause and effect developed in this topic help students to generalize understanding of inheritance of traits to other applications in science.
- Biological concept of species: a species is a group of natural populations which reproduce among them and reproductively isolated and have their own niche in nature. So, a species has common ancestry and share traits of gradual variation. This definition has some problems: it is only applicable in species with sexual reproduction and it is not applicable in extinct species.
- Evolutionary concept of species: a species is a single lineage of ancestor-descendent populations that maintains its identity in front of other lineages and has its evolutionary tendencies and historical destination. This approach and the biological one are, in fact, complementary because they are talking about different phenomenons.
- Phylogenetic concept of species: according to this point of view, a species is an irreducible group of organisms, diagnostically distinguishable from other similar groups and inside which there is a parental pattern of ancestry and descendants. This point of view covers sexual and asexual reproduction.