Biology Final 120-Set 2

Front 1

What are the derived characteristics that distinguish plants from algae?

Back 1

Alternation of Generations, Walled spores produced in sporangia, Multicellular gametangia, Apical meristems

Front 2

What was the primary selective pressure that drove the evolution of land plants?

Back 2

The evolution of land dwelling plant and fungi that brought plants to land. Also better sunlight on land for photosynthesis.

Front 3

What is the general timeline for the types of plants that dominated the terrestrial environment during Earth’s history? Which ones formed the first forests? Which were dominant during the age of dinosaurs? Which dominate now?

Back 3

Bryophytes first came on land as mosses. Seedless vascular plants were the first forests. During the age of the dinosaurs gymnosperms dominated. Angiosperms now dominate life on Earth.

Front 4

What are the major groups of land plants? Be able to write the basic phylogeneitc classification of the plant kingdom (as on pg 1 of the Ch. 29 notes)

Back 4

Land plants can be divided into 2 main groups, based on presence of vascular tissue – cells joined into tubes (xylem and phloem) to transport water and nutrients. Vascular plants can be divided further based on whether or not they produce seeds:Non-vascular plants (Bryophytes): Liverworts, Hornworts, most Mosses
Vascular Plants

Front 5

What are the basic characteristics of the bryophyte life cycle?

Back 5

Spore > male or female gametophyte > sperm released, or egg retained > fertilization > sporophyte grows on gametophyte > spores released

Front 6

How is the life cycle of a fern different than that of a bryophyte?

Back 6

Unlike bryophytes, the sporophyte (2n) is the dominant part of the life cycle in vascular plants – it grows from, but is independent of, the gametophyte

Front 7

What major evolutionary advances can be seen in the ferns and similar species?

Back 7

a.Specialized transport tissues that allowed for greater overall height of the plants
i.Xylem
ii.Phloem
b.True roots likely evolved from the tissue at the base of the stems
c.True leaves – vary in complexity:
i.Microphylls – very simple, small leaves with only a single “vein”
ii.Megaphylls – larger leaves with a highly branched vascular system, which can support much greater photosynthetic productivity
d.Sporophylls – specialized leaves that produce spores.

Front 8

What are the distinguishing characteristics of gymnosperms? What are the basics of their life cycle?

Back 8

-Sporophyte stage dominates in the life cycle
-Cones are the reproductive structures
-The gymnosperms include four plant phyla
a.Largest is Coniferophyta – includes pines, spruces, junipers, etc.
i.Most conifers are evergreens, with the needle-shaped leaves adapted to dry conditions
ii.Much of our lumber comes from conifers
iii.Conifers are among the oldest organisms on Earth
In most conifer species, each tree has both ovulate (female) and pollen (male) cones.
Pollination happens some time before the female gametophyte (egg) has fully formed in the ovule. The female gametophytes form, and each contain multiple eggs (n).
The pollen grain germinates, delivering one or more sperm nuclei that combine with the eggs during fertilization, forming an embryo – a new sporophyte (2n).

Front 9

What are the distinguishing characteristics of angiosperms? What are the basics of their life cycle?

Back 9

-The reproductive adaptations of angiosperms include flowers and fruits
-Angiosperms are usually referred to as flowering plants – vascular, seed-producing ---plants that produce two reproductive structures: flowers and fruit.

Front 10

Flowers: Most flowers have mechanisms that ensure cross-pollination, rather than self-fertilization. What parts of a flower are there?

Back 10

Male: anther and filament
Female: stigma, style, ovary, ovule
Other: petals, sepals.

Front 11

What is heterospory? How does this feature of the seed-bearing plants mean their life cycle differs from the seedless plants?

Back 11

2 types of spores produced in two different parts of the plant (e.g. male and female cones or stamen and carpal of flowers). Seedless plants grow their different parts at different times, for seedless plants they grow their male and female parts at the same time.

Front 12

What is a good example of coevolution that includes angiosperms?

Back 12

Pollinator–plant relationships are examples of coevolution – a mutual evolutionary influence between 2 species

Front 13

What uses have humans found for plants?

Back 13

Today’s agriculture is based almost entirely on cultivation of angiosperms for food. Some of the many examples:
a.Corn, rice wheat, potatoes
b.Coffee beans and tea leaves
c.Cocoa and other spices
Other uses:
d.Building materials – lumber for homes, furniture, etc.
e.Wood pulp for paper
f.Medications such as menthol, morphine and quinine
g.Perfumes and decoration

Front 14

What are the 3 plant organs? The three plant tissue types? The main cell types? Be able to define each.

Back 14

Three basic plant organs: Roots, Stems, and Leaves. Plant organs have dermal, vascular, and ground tissues

Front 15

ROOT SYSTEM.
general anatomy? Their role in acquiring needed substances from the environment?

Back 15

Roots
-Anchors plant in soil
-Absorbs minerals and water
-Store food for “later”
-Monocots – mat of thin, fibrous roots (e.g. grasses)
-Eudicots – taproot system (e.g. carrots) – one large main root with many lateral roots (shown)

Front 16

SHOOT SYSTEM.
general anatomy? Their role in acquiring needed substances from the environment?

Back 16

Shoots
•Two types of shoots: vegetative and reproductive
•Stems have alternating nodes and internodes
•Terminal buds are primary points of growth (show apical dominance)

Front 17

What are the general types of root systems? What are some of the specialized roots and what is/are their roles?

Back 17

prop, storage, "strangling" aerial, butress, pneumatophores

Front 18

Describe the anatomy and functions of stems and leaves of the shoot system.

Back 18

see figure 35.2
Leaves are main source of photosynthesis and stem is what transports water and sap

Front 19

What is apical dominance? How might it be naturally and artificially altered in a growing plant?

Back 19

a.terminal bud gets all the energy for growth unless “removed”, at which point axillary buds break dormancy and grow.
b.If a plant loses its terminal bud then the axillary bud starts to grow.

Front 20

What are some types of MODIFIED STEMS and what is/are their roles?

Back 20

oStolons (“runners” of strawberry plants)
oRhizomes (horizontal, underground stems)
oTubers (e.g. Potatoes – swollen ends of rhizomes used for food storage)
oBulbs (e.g. onions – vertical underground shoots consisting mostly of the swollen bases of leaves that store food)

Front 21

What are some types of MODIFIED LEAVES and what is/are their roles?

Back 21

tendrils, spines, storage leaves, bracts, reproductive leaves.

Front 22

What is the name of the specialized cells of the xylem and phloem? How is their anatomical structure at maturity related to their role in the plant?

Back 22

• Cells of the xylem – tracheids and vessel elements; transport water from roots
o dead at functional maturity – form empty “pipes” for water flow
o highly porous
• Cells of the phloem – sieve-tube members and companion cells
• Sieve-tube elements:
o alive at maturity
o Porous
Companion cells
o Serve sieve-tube elements
o May help load sugars into phloem

Front 23

Describe primary and secondary growth of a plant. How are they different from one another?

Back 23

a. Apical meristems
i. add length to the root and shoot tips – called primary growth.
b. Lateral meristems add “thickness” to the stems – called secondary growth
Primary growth adds length. Secondary growth adds thickness

Front 24

Briefly describe how the processes of growth, morphogenesis and differentiation are related to producing the plant “body”.

Back 24

a. Morphogenesis depends on cells “knowing where they are” in relationship to other cells. If not, you get abnormal growth.
b. Growth- need to know where to grow, such as toward sunlight.
c. Differentiation- is what makes different parts of the plant such as leaves, stems and roots in the right place. Only express certain genes at certain times to make these.

Front 25

How do physical forces influence transport of materials in a plant? Over what scales does transport occur?

Back 25

Physical force of gravity.
Scale is entire plant. Could be a few hundred feet in the air.

Front 26

Flaccid vs. Turgid

Back 26

• Turgid cells have enough water – outward pressure on cell walls allow the plant to maintain its shape.
• flaccid = wilted plant. Not enough water in cells

Front 27

Describe the process of bulk transport of water within the xylem of a plant. What role do the roots, xylem, and stomata play in this process?

Back 27

-Transport in vascular plants occurs at three levels:
a. Short-distance diffusion into/out of individual cells
i. water uptake by root hairs
b. Short-distance active transport of substances from cell to cell
i. sugar “loading” into phloem
c. Long-distance bulk transport – movement of a fluid driven by pressure
i. within xylem and phloem
ii. as leaves transpirate water out of their leaf pressure moves water within the xylem from the roots

Front 28

Describe the translocation of phloem sap in a plant. What is meant by the terms “source” and “sink” in this regard?

Back 28

--Sucrose is moved into sieve tubes via active transport (concentration in sieve tubes can be 2-3x higher than surrounding tissue)
--So, movement of phloem sap is by bulk flow (flow caused by pressure)

Front 29

What are the most important nutrients for a plant?

Back 29

N, S and P are most important nutrients along with C, H and O

Front 30

What substances are plants “made of”?

Back 30

-Plants are about 80-90% water by weight
-Of the remaining material ~95% is organic substances (mostly carbohydrates, including cellulose), with ~5% inorganic ions.
a. So, the majority of a plant is C, H, O.
b. N, S and P are also relatively abundant, since they are part of a number of organic molecules.

Front 31

How might the soil affect the health and growth of a plant?

Back 31

If there is not enough nutrients in the soil then the plant will not be able to absorb nutrients.

Front 32

How do nitrogen-fixing bacteria affect plant nutrition? What kind of relationship do plants and these bacteria have?

Back 32

-Plants must get N via absorption of NH4+ and NO3-
-the only way to get N in these forms is via the actions of nitrogen-fixing and nitrifying bacteria

Front 33

In what other types of “nutritional” relationships do plants participate?

Back 33

• mycorrhizae are modified roots consisting of mutualistic, symbiotic associations of fungi and roots (Figure 37.12)
o The fungus increases surface area for water uptake and selectively absorbs phosphate and other minerals from the soil, while the plant supplies sugar.
o Fungi may also secrete root growth factors and antibiotics.
• Both of these mutualistic associations likely evolved very early during the colonization of land by plants.

Front 34

Describe a pollen grain and an embryo sac. What is/are the role(s) of these two structures in the life cycle of an angiosperm?

Back 34

A pollen grain is a male gametophyte. They are what fertilize the egg. An embryo sac is what protects and feeds the developing plant.

Front 35

What’s the difference between pollination and fertilization in angiosperms? Which happens first?

Back 35

Pollination is the traveling of pollen, usually with an animal or the wind. Fertilization is the actual fertilization of the egg with the pollen.

Front 36

What is double fertilization, and what might be an advantage related to it?

Back 36

In double fertilization:
a. One sperm fertilizes the egg forming the zygote
i. This is a new sporophyte!
b. The other sperm combines with the “helpers” to produce the food-storing endosperm of the seed from the remains of the embryo sac
Ovules > seeds
Ovaries > fruits

Front 37

Where do seeds and fruits come from?

Back 37

Ovules develop into seeds containing the embryo + nutrient supply (Figs. 38.7, 38.8)
Ovary develops into the fruits containing the seeds

Front 38

Germination?

Back 38

Germination starts with H2O absorption, triggering other metabolic changes in the embryo à growth of new plant
Germination is triggered by environmental cues:
a. Rain, temperature change, light

Front 39

What are the possible ways (natural and artificial) for plants to reproduce asexually?

Back 39

-Asexual reproduction in plants is called vegetative reproduction
-Vegetative propagation is common in agriculture – e.g. cuttings and grafting

Front 40

What are the major plant hormones and roles of each?

Back 40

a. Auxin (IAA) – promotes elongation of stems in new shoots, roots, cell differentiation, branching, regulates fruit development
b. Abscisic acid (ABA) inhibits growth, promotes seed dormancy, allows plants to withstand drought
c. Cytokinins – interact with auxins to stimulate cytokinesis (cell division) in roots
d. Gibberellins – stimulate seed and bud germination; growth in both leaves and stems; flowering and fruit development (see Figure 39.10)
e. Brassinosteroids – promote cell expansion and division in shoots; concentration dependent effects on roots; promote seed germination
f. Ethylene

Front 41

What is leaf abscission and what effect do ethylene and auxin have on it?

Back 41

leaf abscission – which occurs in autumn when a leaf falls. (leaf breaks off from tree branches) changes of these hormonal controls signal abscission to occur.

Front 42

What are some of the general ways that plants respond to light?

Back 42

• Plants can detect the direction, intensity, and wavelength of light. Many plant processes (e.g. transpiration, enzyme synthesis) oscillate during the day in response to changes in light levels, temperature, and relative humidity (Figure 39.20).
-Plants also time many events (flowering, seed production, dropping leaves) to seasonal changes in light intensity and day length
-Plants will grow toward the light

Front 43

What are some other stimuli to which plants respond? What are the adaptive advantages of each of these responses?

Back 43

-Roots and shoots respond to gravity for proper growth direction
-Some respond to “touch”:
a. Vines cling with special tendrils that coil only when they touch something
b. The Venus flytrap uses sensory hairs to signal a closing of the leaves

Front 44

43. In general, how do plants defend themselves against herbivores and pathogens?

Back 44

Defense against pathogens:
a. First line of defense is a physical barrier – the cuticle/epidermis/bark
b. Second line of defense is chemical – e.g. antimicrobial, antifungal; other chemicals signal for alteration of localized cell wall structure (putting up a “barricade” within the plant’s tissues)
Herbivores
a.Produce poisons
b.Hard outer layer
c.Thorns