Gen Biology II - Exam 3 - Vocabulary

Monophyletic Group

a common ancestor and all of its descendants

Paraphyletic Group

a common ancestor and some, but not all, of it descendants

Convergent Evolution

similar features evolve independently in different lineages

Phylogeny

the evolutionary history and relationships of organisms

Cuticle

a waxy, resistant layer found in early plant fossils

Sporopollenin

a durable substance surrounding spores and pollen, protecting them from drying found in early plant fossils

Sporangia

structures that produce spores found in early plant fossils

Stoma/Stomata

a pore that allows gas exchange

Guard Cells

specialized cells surrounding the stoma that change shape to open or close the pore

What organisms make up the Viridiplantae?

Green algae and land plants.

Where are green algae important photosynthetic organisms?

Freshwater habitats.

What are the key photosynthesizers in terrestrial environments?

Land plants.

Why are green algae studied with land plants?

They are the closest living relatives to land plants, and land plants evolved from green algae.

What organisms dominated terrestrial life before land plants evolved?

Bacteria, archaea, and single-celled protists.

What made land plants distinctive among early terrestrial organisms?

They could thrive with their tissues completely exposed to air.

Name five major ways people use plants.

Food, fuel, fibers, building materials, and pharmaceuticals.

Name three important industries based on plants.

Agriculture, forestry, and horticulture.

How can plants negatively affect humans or natural areas?

Weeds reduce crop productivity; introduced species degrade natural areas; Ulva can proliferate uncontrollably.

What two broad components make up an ecosystem?

Organisms in an area and the nonliving physical environment.

Name six nonliving ecosystem components listed in the slides.

Atmosphere, precipitation, surface water, sunlight, soil, and nutrients.

Name five ecosystem services provided by green algae and land plants.

Produce oxygen, build soil, prevent erosion/nutrient loss, hold soil water, and moderate local climate.

How do green algae and land plants produce oxygen?

Through oxygenic photosynthesis.

How do plants help build soil?

They provide food for decomposers.

How do plants help prevent nutrient loss?

They hold soil and reduce wind and water erosion.

How can plants moderate local climate?

They provide shade and reduce the impact of wind on landscapes.

What is a primary producer?

An organism that converts energy from sunlight into chemical energy; land plants dominate this role on land.

How do land plants support other terrestrial organisms?

Sugars they produce support virtually all other organisms in terrestrial habitats.

How do plants contribute to the carbon cycle?

They take CO2 from the atmosphere and reduce it to make sugars.

Do land plants fix more CO2 than they release, according to the slides?

Yes; they fix much more CO2 than they release.

How has loss of plant-rich prairies affected atmospheric CO2?

It has contributed to increased atmospheric CO2 concentrations and, partly, rising global temperatures.

What is artificial selection in crop domestication associated with?

Selecting plants with certain properties, leading to dramatic changes in plant characteristics.

Which fuel sources replaced wood in industrialized countries?

Fossil fuels, including coal, petroleum, and natural gas.

What is the slide's connection between fossil fuels and plants?

Fossil fuels are derived from plants, living or long-deceased.

What materials do plants provide for clothing and household articles?

Raw materials for fibers used in clothing, rope, towels, and linens.

What do woody plants provide for construction and manufacturing?

Lumber for houses and furniture, and fibers used to make paper.

About what percentage of U.S. prescriptions include at least one plant-derived molecule?

About 25%.

Why do plants synthesize many compounds used in medicines?

Most of these compounds are synthesized by plants to repel herbivores.

How do botanists study diversification of green plants?

Compare morphological traits, analyze the fossil record, and estimate phylogenetic trees.

What forms can green algae take?

Unicellular, colonial, or multicellular.

What habitats can green algae occupy?

Marine, freshwater, or moist terrestrial habitats.

Where do most green algae live?

Aquatic habitats.

Where do most land plants live?

Terrestrial habitats.

Name four similarities between green algae and land plants.

Similar chloroplast structure, similar thylakoid arrangements, similar cell walls/sperm/peroxisomes, and starch storage in chloroplasts.

What storage product do green-plant chloroplasts synthesize?

Starch.

Which three green-algal groups are most similar to land plants?

Zygnematophyceae, Coleochaetophyceae, and Charophyceae.

What are the common names of Zygnematophyceae, Coleochaetophyceae, and Charophyceae?

Conjugating algae, coleochaetes, and stoneworts, respectively.

What is the common name of Zygnematophyceae?

conjugating algae

What is the common name of Coleochaetophyceae?

coleochaetes

What is the common name of Charophyceae?

stoneworts

What habitat and body form characterize the three green-algal groups most similar to land plants?

They are largely multicellular and live in freshwater.

What is the slide's hypothesis about the origin of land plants?

Land plants evolved from green algae that lived in freshwater habitats.

What is vascular tissue?

Specialized groups of cells that conduct water or dissolved nutrients throughout the plant body.

What defines nonvascular plants?

They lack vascular tissue, include mosses and liverworts (bryophytes), and use spores rather than seeds.

How do seedless vascular plants reproduce and disperse?

They have well-developed vascular tissue but do not make seeds; they use spores.

What example of a seedless vascular plant is named in the slides?

Ferns.

What are the three key parts of a seed described in the slides?

An embryo, a store of nutritive tissue, and a tough protective layer.

What are angiosperms and gymnosperms?

Angiosperms are flowering plants with 'encased seeds'; gymnosperms have 'naked seeds.'

When does the fossil record for green algae begin?

About 700–725 million years ago.

When does the fossil record for land plants begin?

About 475 million years ago.

What does the timing of green-algae and land-plant fossils support?

The hypothesis that land plants are derived from green algae.

What major morphological innovations are highlighted in the land-plant fossil timeline?

Stomata, vascular tissue, roots, and leaves.

What early land-plant features are mentioned in the timeline?

Cuticle, spores, and sporangia.

What are the five major intervals/events in the slide's land-plant diversification timeline?

Early cuticle/spores/sporangia evidence; major morphological innovations; coal-forming swamps; green plants spreading through wet and dry environments; diversification of flowering plants.

What is a cuticle?

A thin, waxy-like, watertight barrier that coats aboveground parts of land plants and helps prevent drying.

What is sporopollenin?

A waxy substance that surrounds spores and pollen in modern land plants and helps them resist drying.

What is a sporangium?

A spore-producing structure; plural is sporangia.

What date range is associated with the Silurian–Devonian explosion in the slides?

416–359 million years ago.

What plant adaptations are present in fossils from the Silurian–Devonian interval?

Most major plant lineages and adaptations for dry terrestrial habitats, including water-conducting vascular tissue and roots.

What helped plants colonize land in conjunction with plant adaptations?

Symbiotic fungi.

What date range is associated with the Carboniferous Period in the slides?

About 359–299 million years ago.

What characterizes Carboniferous coal deposits described in the slides?

Carbon-rich rock containing fossil spores, branches, leaves, and tree trunks.

Which plants account for most fossils in the Carboniferous deposits described?

Seedless vascular plants.

When were gymnosperms prominent in the fossil record?

About 299–145 million years ago.

Name gymnosperm groups listed as living today.

Ginkgoes; redwoods, junipers, and yews; pines, spruces, and firs.

What habitat conditions do gymnosperms grow readily in?

Dry habitats.

When did angiosperms appear, according to the slides?

About 150 million years ago.

Which modern plants are named as descendants of plants that produced the first flowers?

Grasses, orchids, daisies, oaks, maples, and roses.

How are angiosperm pollen grains transported?

By wind or insects; pollen carries cells that later develop into sperm.

What does monophyletic mean in the context of plant phylogeny?

A group includes a common ancestor and all descendants of that ancestor.

Why are green plants considered monophyletic?

A single common ancestor gave rise to all green algae and land plants.

What does paraphyletic mean?

A group includes some, but not all, descendants of a single common ancestor.

Why are green algae considered paraphyletic in the slides?

The group includes some, but not all, descendants of the common ancestor because land plants are excluded.

Which living green-algal group is identified as the closest relative to land plants?

Zygnematophyceae, the conjugating algae.

How many successful transitions from freshwater environments to land are indicated for land plants?

One.

How are nonvascular plants described in the plant phylogeny?

They are the earliest-branching groups and the most ancient living group of land plants, but are paraphyletic.

What is the phylogenetic status of seedless vascular plants versus vascular plants as a whole?

Seedless vascular plants are paraphyletic, while vascular plants as a whole are monophyletic.

What groups make up the monophyletic seed plants?

Gymnosperms and angiosperms.

What major divergence occurred among seed plants?

A major divergence in seed development.

What challenge did plants have to overcome to live on land?

They had to adapt to living and reproducing in a dry environment.

What three problems did early land-plant adaptations help solve?

Preventing water loss, protecting against harmful UV radiation, and moving water to tissues without direct water access.

How does a cuticle help a land plant?

It creates a watertight seal over aboveground parts, helping the plant survive dry environments.

What problem does the cuticle create for plants?

It also keeps CO2 out.

What is a stoma, and what is the plural?

An opening surrounded by specialized guard cells; plural is stomata.

How does a stoma open and close?

Guard cells change shape, opening or closing the pore.

What occurs through the stomatal pore?

Gas exchange.

How does UV light damage DNA?

It causes thymine dimers.

Why were algae less exposed to UV damage than early land plants?

Water absorbs UV light.

What compounds protect many plants from UV damage?

Flavonoids, which absorb UV light.

How did upright growth benefit land plants?

Upright individuals gained better access to sunlight when competition for space and light intensified.

How did the first land plants grow?

They had a low, sprawling growth habit and kept much of their tissue in contact with moist soil.