chapter 8 - systematics Flashcards
Botanical Classification
- Indian writings from 1600 BCE classify plants into different morphological forms
- Chinese writings from 480 BCE have lists of plants with their pharmacological uses
Who is the “Father of Botany”
- Theophrastus, Greece 300 BCE
- student of Aristotle
- produced a list of 500 plants with names
- including the genera Asparagus, Narcissus, and Crocus
Dioscorides
- 40-90 AD
- Materia Medica
- describes medical plants
- was the standard medical reference for 1500 years until the renaissance
Renaissance
- invention of the printing press allowed more information to be recognized and written
- beforehand the information was only passed on orally
- creation of herbals: medical plant identification and preparation books
Who was Carolus Linnaeus
- Swedish botanist, physician, and zoologist
- studied botany because at the time plants were the only medicine available
What did Carolus Linnaeus establish?
- established a consistent taxonomic system that was relatively easy to use
- created the binomial scientific name system
Binomial nomenclature breakdown
- first word is the genus and capitalized
- second word is the specific epithet and lowercase
- generic (genus) name can be used independently but the specific epithet cannot
- names of plants include the author that named them at the end
- Linnaeus: L
- ex. Pisum sativum L. (garden pea)
Solanum lycopersicum collected by Linnaeus, why are they kept?
- kept original specimen
- can now sequence DNA and compare to others for evolution data
- can look at how climate change has affected the number of stomates in plants, most plants have less stomates because of more CO2 in the atmosphere
- can compare new species to it
Flower language
- in the Victorian era messages could be sent with plants
- plants in bouquets had specific meanings
- roses: love, four-leaf clover: luck, olive branch: peace (these even used now)
Common names of plants
- can have same common name for different species
- can have multiple common names for a single species
- ex: Maclura pomifera: bodeck, bow-wood, sage apple, hedge apple, hedge osage, mock orange…
- using scientific name is better for research
Modern taxonomy
- based on morphological, physiological, and molecular evidence
- includes classic hierarchy and taxons
What is the classic heirarchy
kingdom, phylum, class, order, family, genus, species
What is a taxon
any taxonomic rank
What taxon do most botanist research?
family taxons
What is a genus
- a group of species that share many characteristics
- ex. Quercus: oaks
- red oaks and willow oaks are separate species but both fall into the same genus
- share the characteristics of having oak acorns
What is a problem associated with classifying plants morphologically?
- convergent evolution
- in certain habitats UNRELATED species can evolve to look very similar (because of environmental and social factors)
- ex: Cactaceae, Euphorbiaceous, and Asclepiadaceae - all look similar like cactus but are unrelated species
Cladistics
- taxonomic relationships examining evolutionary branching patterns
- cladograms can help determine how related organisms are
What is a clade?
- a branch of a cladogram which includes all common ancestors and all descendants
- clades are monophyletic, natural groupings
- all share a common ancestor
Who is Charles Darwin?
- proposed the evolutionary theory of natura selection
What are the premises of natural selection?
- all members of a species show variation
- populations produce more offspring than can survive
- individuals compete for resources and mates (in plants: who can attract more pollinators)
- individuals best suited to environment pass on more genes, thus population evolves
Can natural selection act on a population of clones?
No, because there is no variability in the genetic information of the population
Saving species through systematics
- tropical rain forests contain 70% of the world’s species
- 250,000 species of angiosperms in which 20K are used by humans as a food source
50% of human calories come from what three plants?
- wheat, rice, corn
How is agriculture inhibiting the future of agriculture?
- a lack of diversity in what is being grown
- creates less genes to alter agriculture in the future
