Making sense of our planet’s many species. Taxonomy Making sense of our planet’s many species.

Which of these species are related?

There are only two main groups here: Perissodactyl mammals Artiodactyl mammals

Within each group, there are more groups: Bovidae Equidae Camelidae Tapiridae Rhinocerotidae Suidae

Think about what you just did: How did you decide how to organize these animal? What guided your choices?

Organizing Life: Requires clear criteria, such as: Anatomy (body structure) Genetic similarity (DNA) Mode of Reproduction Sometimes, behaviour (feeding, communication, locomotion….) It also requires good observation skills & useful tools/methods. Classification helps us make sense of the natural world around us.

Aristotle: The Scale of Nature Greek Philosopher, “father of Biology” Organized all things according to their Psyche (a kind of soul) Vegetative Psyche (lowest – you exist) Animate Psyche (middle – you move) Rational Psyche (highest – you think) Problems: Anthropocentric; Subjective; unable to prove existence of these psyches.

Aristotle: The Scale of Nature Artist Mark Dion did this installation of Aristotle’s idea in New York, 1994

Medieval: Great Chain of Being In Medieval Europe, not a lot of scientific innovation happened. Aristotle was so respected, nobody thought to question his ideas… So they took the Scale of Nature and added a few things to make the Great Chain of Being Intended to link all of Creation into one unifying system, it added Saints, Angels & God at the top, demons below. Problems: Still Anthropocentric; Very Subjective; unsuccessfully fused belief systems & scientific thought.

Medieval: St. Augustine St. Augustine (354 – 386) was an even earlier Christian writer. Believed that the natural world was a reflection of the spiritual world Decided to classify all living things into just three groups: Useful, Harmful & Superfluous Problems: Even more Anthropocentric (useful = to us!); Very Subjective; categories too broad On the up-side, he left out non-living things and supernatural beings….!

Enter Carl Linne – Linnaeus! Swedish botanist, physician & zoologist (1701 – 1778) First systematic classification system, based on physical traits. Publishes his Systema Naturae, 1735 Initially, 3 kingdoms of Life (later 5) Each kingdom had 6 more Taxa: Kingdom, Phylum, Class, Order, Family, Genus & Species. Genus + Species = scientific name Clear, objective, not anthropocentric!

Linnean Classification Kingdom Plantae Fungi Animalia Phylum Anthophyta Basidiomycota Chordata Class Monocotydae Agaricomycetes Aves Mammalia Order Liliaceae Russulales Galliformes Primates Family Lilium Russulalacea Phasianidae Hominidae Genus Boletus Gallus Homo Species longiflorum edulis domesticus sapiens

Organizing Life: Kingdoms? Domains? Large groupings of living things based on broadly- shared common traits Oldest classification method How many? In the distant past, 3; in current use, 5, 6 Five kingdoms are: Monera, Protista, Fungi, Plantae, Animalia. Large groupings of living things based on genetic similarities in DNA More recent method Three domains recognized: Archaea = microbes with ancient form of DNA Prokarya = microbes with no nucleus, more evolved DNA Eukarya = organisms with nucleate cells, eukaryotes.

The Five Kingdoms:

The Three Domains:

Hints for taxonomists: Don’t get frustrated at the unrecognizable Greek & Latin words. Kings Play Chess On Friday, Generally Speaking! All organisms have their own unique species name. An organism with the same word for Genus & species is called a Type Species. When writing a species’ name, it is always Genus + species