Download Chapter 1-Plants in Our World Formation of earth-4.5

Chapter 1-Plants in Our World
Formation of earth-4.5-4.6 billion years ago
Evidence of life from organic material-3.8 billion years ago
Many cyanobacteria are photosynthetic, but these microscopic organisms have a much simpler structure than plants
Photosynthesis
First eukaryotic organisms-1.9-2.1 billion years ago
The eukaryotic nucleus and endomembrane system are
thought to have originated by infolding of the cell
membrane in an ancestor of modern eukaryotic cells.
Modern protist lineages, fungi,animals, and plants
inherited mitochondria from early protists.
First photosynthetic eukaryotic organisms-1.5 billion years ago
Because all modern eukaryotic organisms known to
contain plastids also possess mitochondria, it is thought
that algae acquired plastids after mitochondria through
endosymbiosis
“This eukaryote capable of carrying out photosynthesis via endosymbiosis with its captured
partner is considered the first plant from which all plants are subsequently descended.”
Importance of Photosynthesis
Over millions of years, plants have radiated into several major groups.
Devonian Era-evolution of the first seed plants
Gymnosperms
Gymnosperms
Key innovations in the evolution of land plants were pollen and seeds.
Packaging the embryo into a seed enables plants to surround the embryo
with nutritive tissue, providing for the early survival of the embryo.
Jurassic Period-evolution of flowering plants-200 million years ago
Angiosperms
Cretaceous Period-angiosperm radiation
The diversification of the angiosperms over 100-200 mya was due to selection imposed by interactions with other
plants, fungi bacteria and animals.
There is evidence that the increase in diversity with the origin of seed plants and then evolution of angiosperms followed events
of genome duplication.
The theory that Neanderthals disappeared due to a focused meat-based diet has been laid to rest by recent research by
scientists from the Smithsonian and George Washington University. The evidence they collected shows that
Neanderthals ate grains, seeds, and even palm fruits.
http://www.mnh.si.edu/highlight/Neanderth
al_Diet/
Different plants were available all over the world, and people developed their own unique uses for plants.
Use of flowering plants for food
Plants are defined as organisms that:
1)are multicellular
2)have cellulose cell walls
3)have chlorophyll and are photosynthetic (or originated from photosynthetic ancestors).
4) are adapted to in many ways to life on land (or if aquatic, are descended from land-adapted plants).
Because flowering plants are the most important in terms of human goods and services, they are the focus of this course.
Our definition of a plant becomes more specific to flowering plants:
.
All plants have growth points for shoot and root tips called apical meristems
Root apical meristems are
much simpler, being
primarily root tips.
Shoot apical meristems occur at the tips of
the shoots, buried inside the developing
leaves.
Plants also provide many secondary compounds:
Other plant compounds are important for:
Putting Order into Plant Diversity
Historically, there have been two independent kinds of nomenclature.
1)Common names
2)Scientific names
Through the ages, humans have given organisms common names
Scientific names- (Binomial system)
Carolus Linnaeus (1707-1779) (originally Carl von Linné)
Carl von Linné,
Alexander Roslin, 1775.
Currently owned by and
displayed at the Royal
Swedish Academy of
Sciences.
Scientific names
Two-word name consisting of:
1)
Generic name
2)
Specific epithet
Ex: Zea mays
Generic Specific
name epithet
Generic names
- Generic name (genus name) is treated as a Latin noun.
- Capitalized
- Underlined or written in italics.
What is a genus?
Genera that originate from a common ancestor and share one or
more derived characters are clustered together in a plant family.
https://botanistinthekitchen.wordpress.com/
Specific epithet
Major plant organs
Roots play a variety of roles in plants
-roots anchor plants and absorb water and minerals
-some roots are useful as human food
-roots are important sites of hormone production
-the roots of some plants help support stems
There are two major types of root system:
Adventitious roots develop from the shoot system.
Stems are fundamental plant organs with multiple functions.
grow by activity of apical meristems
-store food materials and sometimes serve as
photosynthetic organs.
-conduct sugars produced in leaves
-transport water and materials from roots
The function of phloem is
primarily the movement of
sugar from one part of the plant
to another.
Xylem is involved in the
transport of water and
(usually) dissolved mineral
nutrients.
Modified stems
Leaves are complex structures composed of 4 main types of tissues:
Modified leaves
Reproductive Structures
If a flower has both androecium and gynoecium (male and
female) it is called a perfect flower.
If only one sex is present, it is an imperfect flower.
Monoecious example
Dioecious example
http://www.nzdl.org
The elaboration of flower shapes, sizes and colors that we see
usually reflects the way in which the flowers are pollinated.
Fruits
Every sexually reproducing flowering plant bears some type of fruit that serves the purpose of protecting the seeds and
dispersing them to areas for germination.
Seeds
Within fruits, there are usually one or more seeds that contain
an embryo, variable amounts of stored food and a protective
coat derived from maternal tissues.
Within fruits, there are usually one or more seeds that contain an embryo, variable amounts of stored food and a protective
coat derived from maternal tissues.
Study outline-Chapter 1-Plants in Our World
Understand important major geologic events in the history of plants (Table 1.1)
-formation of the earth
-evidence of life
-first photosynthetic prokaryotic organism
-definition of photosynthesis (Figure 1.2)
-first eukaryotic organism
-endosymbiotic theory/eukaryotic evolution/mitochrondial evollution
-first photosynthetic eukaryotic organism
-plastid evolution
-importance of photosynthesis in plant evolution
-5 major plant groups that evolved (Figure 1.3)
-bryophytes, lycophytes, ferns, gymnosperms and angiosperms
-evolution of the first seed plants
-gymnosperms– cycads, ginkgophytes, conifers and gnetophytes
-key innovations in the evolution of land plants (pollen and seeds)
-evolution of flowering plants (Figure 1.3)
-characteristics of angiosperms
-angiosperm radiation
-understand important evolutionary changes that was influenced by angiosperm radiation
-morphology, secondary compounds that influenced pollinators and predators,
and genome duplication
-Understand how different plants available around the world influenced diet and culture
-Understand general definition of plants from General Botany and the more specific definition to
flowering plants in the Plants in Our World course
-Understand general structure of apical meristem
-shoot apical meristem (SAM) and root apical meristem (RAM)
-Understand common names vs. scientific names
-Understand the definitions of generic name, specific epithet (Table 1.3), genus and family
-Understand characteristics of major plant organs
-Roots – characteristics of roots; tap vs. fibrous (Figure 1.10); modified root examples
-Stems – characteristics of stems; vascular bundles (Figure 1.12); monocot vs. eudicot stem; modified stem examples
-Leaves – characteristics of leaves (Figure 1.14); leaf examples (Figure 1.15)
-Understand reproductive structures
-flower structure (Figure 1.9); perfect vs. imperfect ; monoecious (Fig. 1.18) vs. dioecious; flower type and pollinator (Fig. 1.20)
-general characteristics of fruits (Figures 1.23 and 1.24)
-general characteristics of seeds; monocot vs. eudicot seed (Figure 1.10);
features of seeds that make them good sources of food