Lecture 17 Flashcards

1
Q

What are 3 reasons that green plants are important? and what are some direct needs to humans?

A
  1. key photosynthesizers (consume CO2 and produce O2) and produce carbohydrates
  2. energetic basis for all terrestrial ecosystems (support all the energy needs for the diversity of animal life)
  3. support “ecosystem services”, like soil production, nutrient recycling, soil stability, atmosphere composition, local weather and climate, surface water flow etc.

needs: food, building material, fuel, fibres, pharmaceuticals, aesthetics

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2
Q

What are the 3 major groups of “algae” defined by pigments: and considered to be POLYMORPHIC clades (different ancestors)

A

Brown algae (many seaweeds like kelp)

Red algae

Not algae : the “blue-green algae” should be called CYANOBACTERIA

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3
Q

What does polymorphic mean?

A

The occurrence of more than one form, as several alleles of a particular gene or winged and wingless forms of the same species

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4
Q

where do most GREEN algae live?

A
  • most live only in aquatic or other wet environments
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5
Q

What are the 4 things that need to be supported during the transition to land?

A
  1. desiccation protection : the ability of an organism to withstand or endure extreme dryness, or drought-like condition
  2. support (growing tall)
  3. gas exchange and transport
  4. reproduction? easy in water: reproductive cells can swim freely
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6
Q

What are some synapomorphies with aquatic green algae and terrestrial plants?

A

characteristics of chloroplasts (photosynthetic organelles)

  • photosynthetic pigments in both include chlorophyll a & b and carotene!
  • thylakoids (stacked membranes) in plant chloroplasts are similar to green algae in structure
  • synthesize starch as a storage product
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7
Q

plants adapted to life on land through what?

A

natural selection!

ex. new mutations: waxy surfaces (cuticle) would reduce drying

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8
Q

explain a basic synapomorphy of land plants?

A

waxy cuticle and stomata (pores)

  • waxy cuticle minimizes water loss through the surface cells
  • stomata can open and close to allow gas exchange while minimizing H2O loss
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9
Q

What is the def of green plant?

A
  • multicellular eukaryotes that are photoautotrophic; a monophyletic group that includes green algae, non-vascular plants, vascular and seed plants
  • produces starch
  • carbon from CO2
  • hydrogen and oxygen from H2O
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10
Q

What does photoautotrophic mean?

A

organisms that can make their own energy using light and carbon dioxide via the process of photosynthesis

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11
Q

What are the 3 basic type of land plants and explain them a little

A
  1. nonvascular plants: do not have vascular tissue to conduct water and provide support (ex. mosses)
  2. have vascular tissue but do not make seeds (ex. ferns)
  3. have vascular tissue and make seeds (ex. flowering plants or angiosperms and gymnosperms)
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12
Q

review the 5 major intervals of the fossil record of land plants

A
  1. origin of land plants : first evidence of land plants: cuticle, spores, sporangia
  2. Silurian-Devonian explosion: most major morphological innovations: stomata, vascular tissue roots, leaves
  3. Carboniferous: club mosses and horsetails abundant: extensive coal-forming swamps
  4. gymnosperms become increasingly abundant: both wet and dry environments blanketed with green plants for the first time
  5. Angiosperms abundant : diversification of flowing plants
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13
Q

at what period did the intial colonization of the land by small, simple plants began the transformation of Earth to a “green planet”?

A
  • Ordovician (before Silurian where new adaptations were well developed)
  • diversification of taxa, and increasing size continued during the Silurian-Devonian “explosion”
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14
Q

What happened in the Silurian Period?

A
  • improved adaptations to land (small plants) with cuticle, stomata, support tissues, spores
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15
Q

What happened during the Devonian Period?

A
  • first trees
  • first seeds
  • first insects
  • first tetrapods
  • also called the “Age of Fishes” with high diversity in salt and fresh water
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16
Q

How can vascular plants grow to tree size?

A
  • due to conduction and support tissues

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17
Q

What’s the synapomorphy of vascular tissues (xylem and phloem)?

A
  • VTallows for efficient transport of water and minerals (xylem) and sugars (phloem)
  • xylem tissues contains LIGNIN which is a tough chemical that provides hard structural support
  • VT allows for true stems, roots and leaves
18
Q

why is wood hard? due to what tough chemical?

A
  • LIGNIN
19
Q

What is the primary wall of plants made of? the secondary wall?

A
  • primary : cellulose
  • secondary : lignin
20
Q

What hardens plant tissues?

A
  • VT (xylem) and lignin
21
Q

What are the 3 selective advantages for improved traits of the plants (growing taller in the Devonian)?

A
  • increased support and reduced height constraints: grow taller and compete for light. PHOTOSYNTHETIC COMPETITION
  • better anchoring (hard roots) and increased access to water and nutrients
  • increased surface area (leaves), photosynthetic capacity, and biomass
22
Q

explain the land plant life cycle

A
  • a multicellular haploid GAMETOPHYTE alternates with a multicellular diploid SPOROPHYTE

ADD THE LIFE CYCLE FORM THE BISC LAB MANUAL

  • spores-mitosis-gametophyte-mitosis-gametes-fertilization-zygote-mitosis-sporophyte-meiosis
23
Q

What do sporophytes produce and how?

A
  • spores are produced by meiosis in the sporangia

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24
Q

What are the spores in land plants protected by?

A
  • outer coat made of sporopollenin, complex waxy polymer that resists drying
  • the inner cells can be dispersed widely and start growing into a gametophyte in proper environments
25
Q

What do gametophytes produce and how?

A
  • gametes
  • eggs and sperms are produced through mitosis
26
Q

which part of the gametophyte produces sperm and which part produces the egg cells?

A
  • Antheridia produces sperm that needs water to reach eggs on another gametophyte
  • Archeogonia produces egg cells
27
Q

Whats the 3rd part of a gametophyte?

A
  • rhizoids
28
Q

explain the fern life cycle

A
  • sporophyte dominant

spores (dispersed by wind) - mitosis - developing gametophyte - mitosis - mature gametophyte - sperm swims to egg - fertilization - zygote (in the archegonium) - sporophyte - mitosis - mature sporophyte - meiosis - spores

29
Q

What happened from Devonian to Carboniferous “coal age”

A
  • seedless vascular plants
  • constraint: moist environments, flagellated sperm needs film of water to swim to egg
  • giant insects!
30
Q

Which 2 plants were gametophyte dominant

A
  • mosses and liverworts
31
Q

Why were there giant insects in the Carboniferous Period?

A

The high oxygen condition of the mid-Carboniferous period and the humid conditions allowed insects to grow very big on land

  • diffusion into insects allowed larger size
32
Q

What is pollen?

A
  • a male gametophyte protected by a spore coat made of sporopollenin
  • the male gametophyte produces sperm to fertilize ovules (eggs) produced by a female gametophyte
  • male gametophytes can travel by wind or animal, and are NOT DEPENDENT ON A FILM OF WATER
33
Q

What is the consequence of seeds and pollen combined?

A
  • freed seed plants form reproducing in moist environments
  • allowed for dispersal
  • colonization of most land surfaces
  • allowed interruption (dormancy) in their life cycle
34
Q

What are the 2 major groups of seed plants

A
  • gymnosperms and angiosperms
35
Q

what are gymnosperms

A
  • naked seed plants
  • include all the living seed plants that are not angiosperms
  • constraint: wind-pollinated and so are dependent on high pollen production and wind dispersal (random) for pollination
36
Q

What are angiosperms?

A
  • flowering plants
  • can use both wind, but especially transfer of pollen by pollinators!
37
Q

Where are the seeds usually formed in gymnosperms?

A
  • mostly formed on the surfaces of cone scales, and can be scattered when the cones dry out and open, or scatter
38
Q

describe the pine life cycle

A

microspore forms pollen grain - mitosis - pollen grain (male gametophyte) - pollination via wind - pollen grain meets the fertilization area - pollen tube delivers sperm to egg - fertilization/mitosis - embryo - seeds disperse via wind or animals - developing sporophyte - mature sporophyte

2 diff pathes
- cones with microsporangia

  • ovulate cone - ovules - megasporangium - meiosis and back to pollen grain meeting the fertilization area
39
Q

What is the consequence of lowers and vector pollination (not just wind)

A
  • insect-pollinated plants are not dependent on the wind and produce much less pollen
  • live at much lower densities, since pollinators come to them. this enhances biodiversity through specialization and speciation
40
Q

how does a fruit help a seed?

A
  • protects it and aid in the dispersal by animals, wind or water
  • the fruits of angiosperms surround and protect the seeds inside the fruits
41
Q

explain the angiosperm life cycle

A

microspore - mitosis - pollen grain - pollination - meets egg at the bottom of carpel (megasporangium - meiosis - megaspore - mitosis - female gametophyte) - double fertilization (unique to angiosperms) - zygote - mitosis - seed - developing sporophyte - mature sporophyte - top of stamen - meiosis - microspore

42
Q

What is the carpel?

A
  • ovary with ovules (eggs)