chapter 23 Flashcards
What in general definition for plants?
multicellular photosynthetic eukaryotes
What are plants thought to have evolved from?
fresh water green algae
What is evidence that all plants evolved from charophytes (a greasy water green algae)?
they all..
- have chlorophylls a and b
- store excess carbohydrates as starch
- have cellulose in their cell walls
all charophytes and all land plants are in the same blade and form a monophyletic group. What does this statement mean?
A monophyletic group includes a common ancestor and all of it’s descendant species. Thus means that charophytes and land plants have shared traits that place them in a monophyletic group.
What charophyte traits are also found in land plants?
- both have same mechanism for forming cell wall
- apical cells allow both to grow in length
- plasmodesmata provide means of communication between cells
- both retain and care for the zygote
What is alternation of generations?
- refers to the life cycle of plants; life cycle has alternating gametophyte and sporophyte generations
- sporophyte (2n) generation produces spores by meiosis; spore is haploid cell that will become the gametophyte
- gamrtophyte (n) generation produces gametes that fuse during fertilization to forms a zygote which will infer do mitosis you become the sporophyte
What are some traits unique to land plants that involve alteration of generations?
- alteration of generation
- both embryo and zygote protected from drying out
- sporophyte produces sporangia
- sporangia produce spores
- spores grow into gametophyte
- gametophytes gametangia produce gametes
What are some traits unique to land plants that don’t involve alternation of generations?
- vascular tissue to transport water and nutrients
- cuticle to provide barrier to water loss
- stomata to regulate water and gas exchange with the atmosphere
- apical tissue which allows the production of complex tissues and organs
What are the four major groups of plants? How are they organized? Provide an example of each.
Nonvascular Plants or Bryophytes: do not have vascular tissue (mosses)
Seedless Vascular Plants: have vascular tissue and produce spores (Lycophytes: club mosses and Pteridophytes: ferns and allies)
Vascular Plants with Seeds:
- gymnosperms- have vascular tissue and produce naked seeds - angiosperms- have vascular tissue and produce flowers that make seeds within a fruit
What is the dominant generation in nonvascular plants? seedless vascular plants? gymnosperms? angiosperms?
nonvascular plants: gametophyte
seedless vascular plants: sporophyte
gymnosperm: sporophyte
angiosperm: sporophyte
What are examples of the Bryophytes or nonvascular plants?
liverworts, horworts, and mosses
What are some characteristics of the Bryophytes or nonvascular plants?
- were first plants to colonize land
- don’t have vascular tissues
- don’t have true roots, stems, and leaves
- are low lying
- are found in moist areas
- gametophyte generation is dominant: produce eggs in archegonia and flagellated sperm in antheridia which need a thin film of water to swim to the egg
- sporophyte generation produces windblown spores
What is the major differences between a Lycophyte and a Pteridophyte?
Lycophytes- have leaves known as microphylls because they have only one strand of vascular tissue
Pteridophytes- have broad leaves with several strands of vascular tissue known as megaphylls
Why are megaphyll plants more “fit” than microphyll plants?
Since they have broader leaves, megaphylls can capture more sunlight and make more food during photosynthesis
What are some examples of the Lycophytes or seedless vascular plants?
club mosses: ground pines, spike mosses, and quillworts
What are some characteristics of the Lycophytes or seedless vascular plants?
- contain xylem and phloem
- have true roots, stems, and leaves
- leaves known as microphylls
- do not produce seeds
- produce spores and use them as dispersal stage
- sporophyte generation is dominant
What are some examples of the Pteridophytes or seedless vascular plants?
ferns, horsetails, whisk ferns
What are some characteristics of the Pteridophytes or seedless vascular plants?
- contain xylem and phloem
- have true roots, stems, and leaves
- leaves known as megaphylls
- do not produce seeds
- produce spores and use them as dispersal stage
- sporophyte generation is dominant
How do gymnosperms and angiosperms differ from seedless vascular plants?
- produce seeds, not spores
- seeds are used as dispersal stage
- are heterosporous
- seed is the sporophyte embryo
- seed coat and stored food allow embryo to survive harsh conditions during long periods of dormancy
How do the types of seed plants today (gymnosperms and angiosperms) differ?
gymnosperms- mostly cone-bearing seed plants (have naked seeds)
angiosperms- produce flowers and fruits with seeds enclosed (have seeds enclosed within ovary)
What are the four groups of gymnosperms? Know examples of each.
- conifers which have cones (pines, spruces, cedars, firs, cypresses)
- cycads (sago palm)
- ginkgoes (ginkgo tree)
- gentophytes (Ephedra)
What is meant by the term monoecious?
one plant has both pollen cones and seed comes
What is meant by the term dioecious?
pollen and seed cones are on separate plants
What are the characteristics of angiosperms?
- flowering plants
- typically heterosporous (have male microspores and female megaspores)
- ovules develop into seeds
- ovary develops into fruit
- include all the fruits, vegetables, nuts and grains that are staples of our diets
- belong to one of two classes: monocots or dicots
