Biol/Envs 160 – Plants

Taught by Stuart Allison

Winter 2013

http://courses.knox.edu/bio160/

What is botany?

Botany is the branch of biology concerned with the study of plants – it is a very old science

Theophrastus – 370-285 BCE

Botanic garden at University of Padua Medical School – 16th Century Illustration

Subfields of Botany• Plant molecular biology – study of molecular and submolecular

processes carried out by plants – much focus on photosynthesis as unique to plants

• Plant physiology – study of how plants capture and transform energy and how they grow and develop

• Plant cytology – study of cell structure, function, and cell life history

• Plant morphology – study of the form of plants• Plant anatomy – study of the internal structure of plants• Plant classification – may also be called taxonomy or

systematics – how plants are evolutionarily classified and named

Subfields of Botany cont’d

• Plant genetics – study of heredity and variation

• Ecology – study of relationships between organisms and their environment – plant ecology focuses on relationships of plants to their environment

• Paleobotany – study of biology and evolution of fossil plants

• Economic botany – study of the uses of plants by people

• Ethnobotany – study of traditional uses of plants by various groups of people

• Agronomy – study of soil management and raising crops

Plants are:

• multicellular, eukaryotes (organisms with a nucleus and subcellular organelles), with cellulose cell walls, almost all plants are capable of carrying out photosynthesis using chlorophyll b and carotene pigments

Plants first evolved on land

• Plants originated on land and many of the adaptations that make them plants arose as a response to life on land – today we recognize four main groups of land plants – about 280,000 species

Four main groups of land plants

• bryophytes – true mosses, hornworts, and liverworts

• pteridophytes – ferns, club mosses, horsetails• gymnosperms – seed plants with a “naked”

seed – conifers, cycads, ginkgos, and gnetophytes

• angiosperms – seed plants with a “covered” or “vessel” seed – the flowering plants

Mosses - Bryophyta

Bracken Fern - Pteridophyte

Sword Fern Sori

Equisetum – Common Horsetail - Pteridophyte

Lycopodium – Big Club Moss - Pteridophyte

Gymnosperm - Ponderosa Pine

Cycad – Sago-Palm - Gymnosperm

Gingko biloba - Gymnosperm

Gnetophyta – Ephedra –Mormon tea - Gymnosperm

Gnetophyta –Welwitschia - Gymnosperm

Rosa californica – Angiosperm

Columbia Lily – Angiosperm

Plants:

• are the base of food chains for almost all life on earth

• modify the atmosphere by releasing oxygen

• store tremendous amounts of carbon in their bodies

• Thus knowledge of plants is essential as we deal with environmental problems

Plants:• constitute the structure of our landscapes

• help form soils

• shelter animals

• control local climates

• refresh the atmosphere,

• and are even capable of cleaning up some pollutants.

• Plants are able to do all of those things because they are so fundamentally different from animals.

“An appreciation of plants is the sign of a superior intellect.”

Plant generations can cross thousands of years

Methuselah – a Judean Date Palm

Arctic lupine

Plants have one major limitation

Mycorrhizae – association between a plant root and fungi

Pollination

Coevolution

• where two or more species evolve in concert with each other so that as one changes, the other changes in response to that change

• “In a broad sense, biological coevolution is ‘the change of a biological object triggered by the change of a related object’.”

• “Coevolution does not imply mutual dependence. The host of a parasite, or prey of a predator, does not depend on its enemy for survival.”

» Quotes from Wikipedia

Human-Dog Coevolution

Human-Dog Coevolution

Apple – desire for sweetness

The sweetest fruit?

Detail from ‘The Fall of Man’ by Goltzius

Tulip – desire for beauty

Cannabis – desire for intoxication

Potato – desire for control