TAXONOMY
AND
CLADOGRAMS
Chapter 19
CAROLUS LINNAEUS
• Perhaps no one in history has contributed more hours of
work to science than Carolus Linnaeus
• Linnaeus is the father of taxonomy, or the science of
classifying organisms.
• Linnaeus developed the binomial standard for naming
organisms (genus and species, Homo sapiens)
• He also organized and classified ALL known plants at the
time according to a system of rules and a hierarchy of
important features
CAROLUS LINNAEUS
• Why is there a need for organization?
– Common names change from country to country, and even within
a country. Its important for scientists to all speak the same
language
– Its just too hard to not have a system of organization. There are
too many species and organisms on the planet to try and just
“wing it.”
– Its not always obvious whether two species are related, or how so.
We need agreement, which means we need a system
• Water buffalo vs a bison
• Salamander vs gecko
• Clydesdale horse vs mustang horse
– Latin is a universal language and, at the time of Linnaeus, most
scholars spoke (it was a high school class at one point). No one’s
feelings would be hurt by using this language.
THREE-DOMAIN SYSTEM
• Since Aristotle, organisms were first organized based on one
question: Do they move (animals) or not move (plants)?
• In the 1880’s German scientist Ernst Haeckel added a 3rd kingdom
to describe single-celled organisms, the protists.
• In 1969, scientists began to create the 5-kingdom system based
on prokaryotic or eukaryotic cells, single-celled or multi-cellular,
and how they obtain energy. The groups were plants, animals,
fungus, protists and monera.
• By 1980, Carl Woese of the University of Illinois argued that the
number of single-celled monera was more than the other four
groups combined and showed tremendous variety by
themselves.
• He proposed combining the other four groups into the category
called “Domain: Eukarya” and separate monera into two other
forms: “Domain: Bacteria” and “Domain: Archaea”
DOMAIN BACTERIA
• Bacteria are prokaryotic organisms.
• They can live in colonies and typically form symbiotic
relationships with other organisms, but they are
unicellular.
• Although some contain pigments for photosynthesis
(cyanobacteria for example), most consume organic
material for chemosynthesis or glycolysis.
• They cause a number of minor and major diseases for
eukaryotes, but are essential to nearly every nutrient
cycle in ecosystems due to their ability to remove waste
from the environment
– 90% of the cells in your body are bacteria
DOMAIN ARCHAEA
• Archaea are also prokaryotic and unicellular organisms.
• The defining characteristic of archaea is their ability to
live in extreme environmental conditions (high/low pH,
salinity, temperature, pressure, light conditions, etc).
• This may be due to their plasma membranes and cell
walls, which are made not of separate phospholipids as
the other domains but instead have strong, branching
designs.
• Archaea are able to obtain nutrients from chemicals
that would be considered toxic by all other species,
such as sulfur, methane, benzenes, and phenols
DOMAIN EUKARYA
• Eukarya are the eukaryotic, multicellular organisms on the
planet (or single-celled, eukaryotic organisms).
• The four kingdoms within eukaryotes are animalia, plantae,
fungi, and protists
• Other common traits of eukaryotes include sexual reproduction,
although the life cycles are incredibly different
• Due to their complexity, eukaryotes are believed to have arisen
due to multiple mutations and combinations of prokaryotic cells
• As such, these organisms are much younger than the prokaryotic
organisms
• The multicellular, eukaryotic conditions of these organisms
allow them to have thousands of more functions than
prokaryotes, but also thousands of more requirements to remain
alive
DOMAIN EUKARYA: PROTISTS
• Protists are defined by being a eukaryotic cell that
primarily lives in colonies of single-celled organisms
• Protists contain six separate phyla within their
kingdom
– Green algae and Red algae
– Brown algae, diatoms, water molds
– Euglenas
– Amoebas, slime molds
– Foraminifrins and radiolarians
– Choanoflagellates
• *Be able to name these organisms as protists, not by
their different phyla.*
DOMAIN EUKARYA: FUNGI
• Fungi are eukaryotic cells, form spores for reproduction, lack
flagella for motility, and have chitinous cell walls (not cellulose)
• Although the fossil record for fungi is weak, fungi appear to be
more closely related to animals than plants
• Fungi obtain nutrients through saprotrophic mechanisms (they
release digestive enzymes to break down organic matter, then
absorb nutrients through their cells)
• Fungi have five recognized phyla
– Club fungi (mostly edible mushrooms)
– Sac fungi (cup fungus)
– AM fungi (Glomerales)
– Chytrid fungi (Aquatic fungus)
– Zygomycota (Black mold)
DOMAIN EUKARYA: PLANTAE
• Plants are defined as eukaryotic, photosynthetic,
multicellular organisms with cellulose-based cell walls.
They are also one of two groups with clearly defined
separate tissues that build their bodies
– They also have a crazy reproductive system called
the alternation of generations—more on that later.
• Plants have four recognized phyla (more on these in
our plant unit later)
– Bryophytes (moss, liverworts, hornworts)
– Tracheophytes (ferns, horse tails, club mosses)
– Gymnosperms (conifers, cycads, ginkgos, gnetals)
– Angiosperms (flowering plants)
DOMAIN EUKARYA: ANIMALIA
• Animals are known for their extreme adaptations for
motility (movement), relying primarily on respiration for
energy, and an enormous catalog of organs and tissues
that create different features and functions for animals.
• Animals are branched first into vertebrates or
invertebrates (based on the presence of a backbone)
– Human bias: we’ve named an entire category of
animals based on what they DON’T have, even though
invertebrate species outnumber vertebrate species
11:1
• America and Non-America
• Land and Non-Land
DOMAIN EUKARYA: ANIMALIA INVERTEBRATES
• Eleven phyla make up the invertebrate groups
– Echinoderms (starfish, urchins, sand dollars)
– Arthropods (insects, arachnids, crustaceans)
– Nematoda (roundworms)
– Annelids (worms and leeches)
– Mollusca (squids, slugs, snails)
– Platyhelminthes (flatworms)
– Rotifers (ascomores)
– Lophoporans (brachiopods)
– Ctenophores (comb jellies)
– Cnidarians (jellyfish, anemones, corals)
– Sponges
DOMAIN EUKARYA: ANIMALIA VERTEBRATES
• The vertebrate branch contains five major groups of phyla
– Fish (although the types and numbers of species in this group
are more than the other three groups combined)
• Contain jaws, bones, and lungs
– Amphibians
• Development of four limbs
– Reptiles and birds (simultaneously appear in the fossil
record)
• Development of external eggs with protective shells
• Birds have feathers, hollow bones, and are warm-blooded
• Reptiles have scales, flexible bones, and are cold-blooded
– Mammals
• Internal eggs, production of milk in mammary glands, fur
EXTRA CREDIT QUESTION
• This question is worth an extra 5% on your essay exam
• You may check your answers with me ahead of time for a
yes or no response as many times as you like.
• The warty hammer orchid is a plant whose flower has developed
to both look and smell like a like a female wasp’s body during
ovulation (ready to be impregnated)
• The male wasp lands on the flower attempting to mate with it.
In the process, the wasp collects pollen on its body which it then
carries to the next WH orchid plant in another attempt to mate.
• Without a brain or an ability to plan, reason, observe, or infer,
explain in no more than a 3-5 sentence paragraph how a flower
develops into the perfect shape and scent to trick a wasp into
mating with it.