BIOL 119 Chapter Notes - Chapter 31: Non-Vascular Plant, Ecosystem Services, Paraphyly
Ch. 31- Green Algae and Land Plants
• green algae- traditionally considered protists; more sense to study
them with land plants
o closest living relatives to land plants and form a monophyletic
group
o the transition from aquatic to terrestrial life occurred when land
plants evolved from green algae
• land plants were first organisms that could thrive with their tissues
completely exposed to the air
Plants Provide Ecosystem Services
• ecosystem- consists of all the organisms in a particular area and the
physical components of the environment
• green algae and land plants provide ecosystems services
o enhance life-supporting attributes of atmosphere, surface
water, soil, and physical components of an ecosystem
o alter the environment in ways that benefit many other
organisms
• plants produce oxygen- photosynthesis
• build and hold soil- fallen leaves etc. are food; root networks hold soil
particles in place
• hold water and moderate climate- take up and retain water, provide
shade and increase relative humidity
• Primary producers- dominant primary producers in terrestrial
ecosystems; land plants are the key in the carbon cycle- take CO2 from
the atmosphere and reduce it to make sugars
Plants Provide Humans with Food, Fuel, Fiber, Building Materials, and
Medicines
• Food- artificial selection
find more resources at oneclass.com
find more resources at oneclass.com
2
• Fuel- wood burning, coal, petroleum, natural gas
• Fiber/Building materials- nylon, polyester, cotton wood for building
houses, papermaking
• Pharmaceuticals- steroids, menthol
32.2 How do Biologists Study Green Algae and Land Plants?
• Morphological Traits
o Similarities: green algae are close to land plants due to similar
key traits in two groups
• Major differences among land plants: nonvascular plants, seedless
vascular plants, seed plants with vascular tissue
• Origin- most fossils that date from 60 million years ago are
microscopic and consist of reproductive cells (spores) and sheets of
waxy coating called cuticle
• Silurial-Devonian Explosion- rocks dated 416-359 mya, biologists find
fossils from most of the major plant lineages. Virtually all of the
adaptations that allow plants to occupy dry, terrestrial habitats were
present
• Carboniferous Period- Because coal formation is thought to start only
in the presence of water, Carboniferous fossils indicate the presence
of extensive forested swamps
• Gymnosperm Diversification- gymnosperms grow in readily dry
habitats, biologists infer that both wet and dry environments on the
continents became blanketed with green plants for the first time
during this time period
• Angiosperm Diversification- according to fossil record, green algae
appear first, followed by nonvascular plants, seedless vascular plants,
and seed plants. Organisms that appear late in the fossil record are
often less dependent on moist habitats than groups that appear
earlier
• Molecular phylogenies
o Green plants- monophyletic
o green algae- paraphyletic
find more resources at oneclass.com
find more resources at oneclass.com
3
o Charophyceae- closest living relative to land plants
o Land plants- monophyletic
o Nonvascular plants- earliest-branching groups among land
plants
o Nonvascular plants- paraphyletic
o Seedless vascular plants- paraphyletic; vascular plants-
monophyletic
o Seed plants- monophyletic
o Gymnosperms- monophyletic
o Angiosperms- monophyletic
31.3- What themes occur in diversification of land plants?
Powerpoint Notes
Plants provide ecosystem services
• Producing oxygen via oxygenic photosynthesis
• Building soil- providing food for decomposers
• Holding soil and preventing nutrients from being lost to wind or water
erosion
• Holding water in the soil
• Moderating local climate- provides shade and reduces the impact of
wind on landscapes
Plants are Primary Producers
• Convert solar energy to chemical energy
• Sugars produced by land plants support virtually all other organisms in
terrestrial habitats
• Provide most of our food supply and fuel, fibers, building materials
and medicines
• Food- agricultural research began with the initial domestication of
crop plants
o Artificial selection- for plants with certain properties has led to
dramatic changes in plant characteristics
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Plants provide humans with food, fuel, fiber, building materials, and. Medicines: food- artificial selection, fuel- wood burning, coal, petroleum, natural gas, fiber/building materials- nylon, polyester, cotton wood for building houses, papermaking, pharmaceuticals- steroids, menthol. Organisms that appear late in the fossil record are often less dependent on moist habitats than groups that appear earlier: molecular phylogenies, green plants- monophyletic, green algae- paraphyletic. 2: charophyceae- closest living relative to land plants, land plants- monophyletic, nonvascular plants- earliest-branching groups among land plants, nonvascular plants- paraphyletic, seedless vascular plants- paraphyletic; vascular plants- monophyletic, seed plants- monophyletic, gymnosperms- monophyletic, angiosperms- monophyletic. Nonvascular plants- lack vascular tissue, specialized groups of cells that conduct water or dissolved nutrients throughout the plant body, includes mosses. Fossil record: fossil record for green algae begins 700-725 mya, land plants fossil record begins 475 mya, 5 major events in the diversification of land plants.
