Transcript CB098-008.30_Intro_to_Botany

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
A
stored as starch.
M
• Many plants are green.
o
s
• Eukaryotic
s
• Cell walls are made of cellulose.
• Multicellular
• Plants are organized into nonvascular and
vascular (contain transport vessels).
• 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.
Ecological Services of Plants
• 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.
Scientific Method
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.
1.
2.
3.
4.
Observation
Hypothesis
Experiment
Conclusion.
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
Disciplines
Now see
them all
together.
A Brief Survey of Plant Classification
This 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 Classification
All 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.
Here is the taxonomy for a tulip tree.
Doman: Eukarya
Tulip Tree
Kingdom: Plantae
Liriodendron tulipifera
Division: Magnoliophyta
Class: Magnoliopsida
Order: Magnolioles
Family: Magnoliaceae
Note the endings to
the taxonomic levels
in the plant
kingdom.
Division  -phyta
Class 
-opsida
Order 
-ales
Family 
-aceae
Genus: Liriodendron
Species: tulipifera
Note: The division known as Magnoliophyta is the same as Anthophyta
Plant Classification
Cladistics – 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,
which improve the absorbing
Corn Smut on Corn
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 Sea
The 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
Phytoplanker, which is a
Volvox
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
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