Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

50 Cards in this Set

  • Front
  • Back
What do green plants consist of?
• The green plants consist of the green
algae and land plants.
•Green algae have traditionally been
considered protists, but we study them
along with land plants for two reasons: (1)
they are the closest living relatives to land
plants, and (2) the transition from aquatic
to terrestrial life occurred when land plants
evolved from green algae.
Why Do Biologists Study the Green Plants?
• Agriculture, forestry, and horticulture are among the
most important endeavors supported by biological
•Tens of thousands of biologists are employed in
research designed to increase the productivity of
plants and create new ways of using them that benefit
•Plants Provide Ecosystem Services
–Plants produce oxygen via oxygenic photosynthesis, build
soil by providing food for decomposers, hold and prevent
nutrients from being lost by erosion by wind and water
(Figure 29.1), hold water, and moderate the local climate.
Why Study Plants?, cont.
• Land plants are the dominant primary producers in
terrestrial ecosystems and are key to the carbon cycle
on continents (Figure 29.2).
•Plants are eaten by herbivores, which are eaten by
carnivores, which are eaten by
omnivores—organisms that eat both plants and
animals. Omnivores feed at several different levels in
the terrestrial food chain.
Describe the process of artificial selection.
•Humans have actively selected seeds
to plant the next generation of crops,
a process called artificial selection
(Figure 29.3).
Name some plant-based fuels and fibers.
• In addition to food, humans have depended on
plants for cooking and heating fuels and as a source
of fibers for clothing and other things (Figure 29.4).
•Wood has been replaced by other fuels (some of
which came from ancient plants). Today, the primary
interest in woody plants is for building materials and
fibers used in papermaking.
What is bioprospecting?
• Bioprospecting is the effort to find naturally
occurring compounds that can be used as drugs,
fragrances, insecticides, herbicides, or fungicides.
Some drugs derived from land plants are listed in
Table 29.1.
What are hydroponics?
•Hydroponics, the liquid culture of plants, can be
used to harvest large quantities of plant chemicals.
What do ethnobotanists study?
•Ethnobotanists study how humans use plants and
research new uses for plants.
How Do Biologists Study Green Plants?
• To understand how green plants originated and
diversified, biologists use three tools:
1. They compare the fundamental morphological
features of various green algae and green plants;
2. They analyze the fossil record of the lineage; and
3. They assess similarities and differences in
molecular traits such as the DNA sequences from
selected genes.
The 12 most important phyla of
land plants are grouped into three
categories...what are they?
nonvascular plants
seedless vascular plants
seed plants
Nonvascular Plants?
–Liverworts and hornworts lack vascular
tissue—specialized groups of cells that conduct
water or dissolved nutrients from one part of the
plant body to another.
–Mosses have some tissues that can transport
water, but lack reinforced cell walls typical of
true vascular tissue
Seedless vascular plants?
•Whisk ferns
–Have well-developed vascular tissue
–Do not make seeds
•A seed consists of an embryo and a store of
nutritive tissue, surrounded by a tough
protective layer.
Seed plants?
•Five major lineages:
•Have vascular tissue
•Make seeds
The gnetophytes, cycads, ginkgoes,
and conifers are collectively known
as __________, because their seeds
do not develop in an enclosed
structure (naked).
In the flowering plants, or
__________, seeds develop inside a
protective structure called a carpel.
• The fossil record for land plants
began ____ million years ago. It is
massive and is broken up into five
segments, each of which
encompasses a major event in the
diversification of land plants (Figure
What are the steps for evaluating Molecular Phylogenies?
1. Land plants probably evolved from green algae.
2. The green algal group called Charales is the sister
group to land plants—meaning that Charales are
their closest living relative.
3. The green algae group is paraphyletic.
4. The land plants are monophyletic.
5. The nonvascular plants are the most basal groups
among land plants.
6. Morphological simplicity of the whisk ferns is
probably a derived trait.
7. Seeds and flowers evolved only once.
How did plants adapt to dry conditions?
• Plants had to adapt to conditions in which
only a portion of their tissues were bathed in
•The adaptation to the water problem arose in
two steps:
–preventing water loss from cells
–transporting water from tissues with access
to water to tissues without access.
Plants prevent water loss in what 2 ways?
Cuticle and Stomata
• Cuticle is a waxy, watertight sealant
that gives plants the ability to survive
in dry environments.
•Gas exchange is accomplished by
stomata, which have a pore that
opens and closes (Figure 29.10).
Transporting Water: Vascular Tissue and
Upright Growth
• The first land plants probably lacked rigidity and
were low and sprawling. Early upright land plants
were able to pump water into cells and became rigid
due to turgor pressure.
•Vascular tissue evolved in a series of gradual steps
that provided an increasing level of structural
support, allowing plants to grow upright (Figure
How Do Plants Reproduce
in Dry Conditions?
•All land plants undergo alternation of
•Have a multicellular haploid phase called the
•Have a multicellular diploid phase known as
the sporophyte
•The relationship between gametophyte and
sporophyte is variable (Figure 29.14)
Variation in Alternation of
• The sporophyte is small in bryophytes, larger
in ferns, and dominant in gymnosperms and
The male gamestophyte of seed plants is reduced to a microscopic structure call a ___________?
Pollen grain
Seed plants can produce two distinct types of spores and spore-producing structures. This development is know as what?
What were the two evolutionary changes that occurred in the early history of land plants?
–Gametes were produced in complex multicellular
structures (Figure 29.16)
•Gametangia (antheridia and archegonia)
–The embryo was retained on the parent and
nourished (Figure 29.17).
•The embryo does not need to find its own resources
–Based on this innovation, biologists call the land
plants embryophytes.
The Evolution of Pollen
• When pollen evolved, seed plants lost their
dependence on water for fertilization.
•In the sporophyte-dominated gymnosperms and
angiosperms, the male (sperm producing)
gametophyte is reduced to a pollen grain
–The pollen grain is a male gametophyte surrounded
by a tough outer coat to reduce dessication
–When it lands near the egg, the pollen grain
releases the sperm cells used in fertilization
•This advance removed the dependence on water
for fertilization (sexual reproduction).
The Evolution of the Seed
• A seed is a structure that encloses and protects a
developing embryo.
•Seeds are often attached to a structure that aids
in dispersal by wind, water, or animals (Figures
29.18 and 29.19).
•In angiosperms, the seed is surrounded by a
–Fruit aids in the dispersal of seeds by animals.
–An _____ ______ occurs when a single lineage produces a large
number of descendant species that are adapted to a wide variety of
Adaptive radiation
•Angiosperms represent one of the great adaptive radiations in
the history of life.
• Angiosperms are the most diverse land plants living today.
–About 250,000 species have been described, and more are discovered
each year.
•The success of angiosperms in terms of geographical
distribution, number of individuals, and number of species
revolves around a reproductive organ: the flower (Figure 29.20).
•Angiosperm diversification is associated with what three key
•Angiosperm diversification is associated with three key
(1) vessels
(2) flowers
(3) fruits
–Angiosperm diversification is closely tied with the diversification of
animals, particularly insects
Key Lineages of
Green Plants
• The evolution of cuticle, pores,
stomata, and water-conducting tissues
allowed green plants to grow on land,
where resources for photosynthesis
are abundant.
Facts about Green Algae
• The green algae are a paraphyletic group that
totals about 7000 species.
•They have a double membrane and chlorophylls
a and b, but relatively few accessory pigments.
•Green algae live in close association with other
organisms, such as fungi and cyanobacteria.
•Member groups include:
–Charales (Stoneworts)
Ulvobionta (green algae)
–Most green algae you have seen belongs to this
group (e.g., Volvox). They are important primary
producers in aquatic areas (Figure 29.27).
Coleochaetales (green algae)
–Most grow as flat sheets of cells (e.g., water lilies),
and the multicellular individuals are haploid
(Figure 29.28).
Charales (Stoneworts)(green algae)
–They commonly accumulate crusts of calcium
carbonate over their surfaces. They can form
extensive beds on lake bottoms (Figure 29.29).
Nonvascular Plants (“Bryophytes”)
• The nonvascular plants, or bryophytes, are the
most basal lineages of land plants.
•The three lineages with living representatives
(liverworts, hornworts, and mosses) do not form
a monophyletic group, but instead represent an
evolutionary grade.
–Hepaticophyta (Liverworts)
–Anthocerophyta (Hornworts)
–Bryophyta (Mosses)
Hepaticophyta (Liverworts)
–Liver-shaped leaves; can grow on bare rock or tree
bark, which helps in soil formation (Figure 29.30).
Anthocerophyta (Hornworts)
–The sporophytes look like horns and have stomata
(Figure 29.31).
Bryophyta (Mosses)
–Mosses can be abundant in extreme environments
and can become dormant. Sphagnum species are
among the most profuse (Figure 29.32).
Seedless Vascular Plants
• The seedless vascular plants are a paraphyletic
group that forms a grade between the
nonvascular plants and the seed plants.
•All species of seedless vascular plants have
conducting tissues with cells that are reinforced
with lignin, forming vascular tissue.
–Lycophyta (Lycophytes, or Club Mosses)
–Psilotophyta (Whisk Ferns)
–Sphenophyta (Horsetails)
–Pteridophyta (Ferns)
–(Lycophytes, or Club Mosses) Lycopods are the most
ancient plant lineage with roots. Tree-sized lycophytes
dominated the coal-forming forests of the Carboniferous
period (Figure 29.33).
Psilotophyta (Whisk Ferns)
–Whisk ferns are restricted to tropical regions and have no
fossil record (Figure 29.34).
Sphenophyta (or Equisetophyta) (Horsetails)
–Horsetails can flourish in waterlogged soils by allowing
oxygen to diffuse down their hollow stems (Figure 29.35).
Pteridophyta (Ferns)
–Ferns are the only seedless vascular plants to have large,
well-developed leaves (Figure 29.36).
Seed Plants
• The seed plants are a monophyletic group
–Consists of the gymnosperms and the angiosperms.
–Defined by the production of seeds and pollen grains.
Gnetophyta (Gnetophytes)
–There are three living genera; the drug ephedrine has been
isolated from this group (Figure 29.37).
Cycadophyta (Cycads)
–They harbor large numbers of symbiotic, nitrogen-fixing
cyanobacteria, which are important sources of nutrients
(Figure 29.38).
Ginkgophyta (Ginkgoes)
–One species is alive today. It is deciduous, and individual
trees are either male or female (Figure 29.39).
Coniferophyta (Conifers)
–Named for its reproductive structure, the cone.
Conifers dominate all high-latitude and high-altitude
forests (Figure 29.40).
Anthophyta (Angiosperms)
–The defining adaptation of angiosperms is the
–Flowering plants supply the majority of food that
supports virtually every other land species (Figure
–Also produce fruit for dispersal of the seed