Botany (Plant Biology)• Botany is the study of

plants or plantlike relatives.

• It is estimated that there are about 300,000 to 500,000 species of plants alive today.

• Plant-like relatives include certain bacteria, fungi, and algae, which themselves total about 1 million species.

General Characteristics of Plants• Photosynthesis

• Autotrophic (A.K.A. Producers) - Plants are self-feeders. They produce their own food.

• Their surplus carbohydrate is stored as starch.

• Many plants are green.• Eukaryotic• Cell walls are made of cellulose.• Multicellular• Plants are organized into nonvascular and

vascular (contain transport vessels).

A

Moss

• Belong to the Kingdom Plantae. Plantae (the plant kingdom) is divided into divisions instead of phyla.

• Many types – Trees, shrubs, herbs, grasses, ferns, mosses, algae.

• Plants provide food for humans. Most of the human population depends on the following plants for survival: rice, beans, soy, corn and wheat.

• Plants provide fabric, shelter, medicine and energy (burning of firewood and biofuels).

• Oxygen gas (O2) and organic nitrogen are produced by plants.

• Plants build new land, stabilize soil and prevent erosion.• Plants provide habitat structure for insects and wildlife.• Plants aid in temperature control and affect climate.• Plants of course die, decompose, and plants cycle

essential mineral nutrients in ecosystems.

Ecological Services of Plants

Scientific Method

1. Observation

2. Hypothesis

3. Experiment

4. Conclusion.

In order to understand the study of plants, we must understand the scientific method. To the right is a diagram.

Below is an abbreviated version of the scientific method.

After the conclusion, a scientist can repeat the entire process if the hypothesis is not supported.

Studying Plants from Different Perspectives

• Any plant is a product of 2 interacting components.1) The plant’s Genetic (Inherited) Material.

This is Plant Genetics.

2) The plant’s Environment in which it lives.

This is Plant Ecology.

• Compared to a psychological point of view for humans defining who we are, this is nature (genes) versus nurture (environment).

Plant Genetics• Plant Genetics is the study of plant heredity.• Underneath this broad discipline we have other disciplines.

Plant Evolution - The study of the change in genetics of plant populations through time.

Plant Systematics – The study of the organization of plant diversity into groups based on evolutionary relationships.

Plant Taxonomy – The science of naming, describing, and classifying plant life.

Systematics and Taxonomy are often used interchangeably.

Plant Ecology

• Plant Ecology is the study of how the environment affects the plant organism.

• Underneath this broad discipline we have other disciplines.

Plant Paleoecology – is used to understand past vegetation and climates based on plant fossil evidence.

Plant Biogeography – is the study of geographic distribution of plants from the present and past.

Plant Metabolism• Integrating these 2 main plant components (genes and

environment), we not only have the plant but more specifically the plant’s metabolism.

• PLANT METABOLISM is one way in which genes and environment become integrated. It is the process in which plants perform photosynthesis, transport materials internally, construct molecules and use hormones.

• The study of plant metabolisms includes more disciplines.

Plant Physiology - the science of plant function, processes and activities.

Plant Molecular Biology - the study of the interaction of biochemistry and genetics in the life of a plant.

• So genes, the environment and metabolism determine an individual plant.

More Plant Disciplines• Plant Morphology is important in the development of a

plant. Plant morphology is the study of how a plant develops from a single cell into diverse tissues and organs and an array of outer surfaces and shapes. This is the study of form and form development.

• Plant Anatomy – is the study of a plant’s internal structure, its tissues and cell types.

• Disciplines based on taxonomy:

Microbiology – study of bacteria.

Mycology – study of fungi.

Phycology – study of algae.

Bryology – study of mosses.• Dendrology – study of trees. This is not a taxonomic

discipline because trees are from different taxonomic groups. Example: Flowering Trees and Conifers.

Plant Biology

DisciplinesNow see them all together.

A Brief Survey of Plant ClassificationThis is taxonomy, which is based on systematics, which is based on evolution, which is based on genetics. See how we are working backwards.

Genus and species is a plant’s scientific name. When writing it, you need to capitalize the plant’s genus, lowercase its species and underline or italicize the entire scientific name.

Plant ClassificationAll life on earth belongs to one of 3 domains. They are Bacteria, Archaea and Eukarya. Organisms that belong to the domain Eukarya (Know as Eukaryotes, which have a nucleus around the DNA and complex organelles) are broken down into 4 kingdoms. They are Animalia, Protista, Fungi, and Plantae. Protista is arguably many kingdoms together but for our purposes, we are considering it to be one kingdom. Animalia, Plantae and Fungi are multicellular while Protista is unicellular.

Note the endings to the taxonomic levels

in the plant kingdom.

Division -phyta

Class -opsida

Order -ales

Family -aceae

Note: The division known as Magnoliophyta is the same as Anthophyta

Here is the taxonomy for a tulip tree.

Doman: Eukarya

Kingdom: Plantae

Division: Magnoliophyta

Class: Magnoliopsida

Order: Magnolioles

Family: Magnoliaceae

Genus: Liriodendron

Species: tulipifera

Tulip Tree

Liriodendron tulipifera

Plant ClassificationCladistics – A set of quantitative methods and concepts for generating hypotheses about the evolutionary relationships among taxa (any taxonomic rank, e.g. order or class); a form of systematics that show evolutionary relationships among organisms by arranging them in a branching diagram (a cladogram), each branch representing organisms that share certain derived traits.

Cladogram (a.k.a Phylogenetic Tree) - A diagram presenting a hypothesis on the sequence of branching events that occurred to generate a given set of present day taxa from their common ancestor. A cladogram is a diagrammatic representation of evolutionary relationships for a group of organisms.

Cladograms show shared features inherited from a common ancestor. Taxonomy and Systematics are based on evolutionary groupings. The more we understand relationships, the more we need to change names & lineages.

Cladogram or Phylogenetic Tree

Note: B’s closest relative is C. A,B,C are closely related. A node represents the most recent common ancestor of the lineages that break off. On this cladogram. The top represents today and as you go down, you are traveling back in time.

The Domains Bacteria & Archaea Include Photosynthetic Bacteria

Organisms that belong to the Domains Bacteria & Archaea are prokaryotes and thus are made of prokaryotic cells. Their cells have circular DNA not bound by a nucleus. The cells are small and do not have organelles. Bacteria can be decomposers and pathogens.

Cyanobacteria or Blue-green Algae are photosynthetic bacteria, which have the pigment chlorophyll for photosynthesis. These bacteria have cell walls made of peptidoglycan (2 rows of amino sugars joined by peptide linkages).

Many Cyanobacteria species also have the unique capability of Nitrogen Fixation, which is the ability to incorporate inorganic nitrogen gas (N2) from the atmosphere into organic nitrogen in the form of Ammonnium (NH4

+).

The Kingdom Fungi contains Decomposers and Pathogens

The kingdom Fungi belongs to the Domain Eukarya. Fungi like Animalia are eukaryotes, which do not photosynthesize. Fungi includes molds, mildew, mushrooms, toadstools, rusts, and smuts. Fungi are mostly terrestrial and have cells walls made of chitin. They reproduce by spores and are known as important DECOMPOSERS. Fungi often have important relationships with the roots of plants,

Corn Smut on Cornwhich improve the absorbing capacity of the plant’s root systems. Considering human food, yeast fungi is important in producing cheese, leavened bread and alcoholic drinks. Fungi such as Penicillium have been important in producing antibiotics. Fungi are also important pathogens of animals and plants.

Protists Include the Grasses of the SeaThe kingdom Protista include animal-like (protozoa), fungi-like and plant-like (photosynthetic) protists. They are generally unicellular but can be colonial like volvox. Protists are usually aquatic. Algae, which performs photosynthesis are single cells or clusters, filaments, sheets or 3-dimensional. Algae are important producers for many aquatic food chains. Microscopic algae are called Phytoplankton or

VolvoxPhytoplanker, which is a photosynthetic organism (generally one-celled) that is part of the plankton, a body of floating cells near the surface of fresh or saline bodies of water. Phytoplankton (grasses of the sea) make ½ of all the oxygen gas in the atmosphere.

Kingdom Plantae

The kingdom Plantae includes all the plants. Many live in water but most are adapted for life on land. Plants are much more complex organisms than Bacteria, Fungi or Protists.

Redwood Forest

BIO 141 Botany with Laboratory

• This product is sponsored by a grant awarded under the President’s Community-Based Job Training Grants as implemented by the U.S. Department of Labor’s Employment and Training Administration. The information contained in this product was created by a grantee organization and does not necessarily reflect the official position of the U.S. Department of Labor. All references to non-governmental companies or organizations, their services, products, or resources are offered for informational purposes and should not be construed as an endorsement by the Department of Labor. This product is copyrighted by the institution that created it and is intended for individual organizational, non-commercial use only.