PWS Homework Questions 3

Identify three specific characteristics that have made angiosperms so dominant on earth and explain why those characteristic have contributed to their success.

1. Basically, angiosperms have gotten extremely good with sexual reproduction. a. They produce flowers, which allows pollination and fertilization success independent of environmental conditions and often promotes cross breading which increases genetic variation b. They have a dominant sporophyte plant which acts more or less as an "involved parent" a.k.a. the gametophyte is reduced (a few cells) and supported by a sporophyte The embryo is enclosed in a seed, which is enclosed in a fruit.

What are the shared characteristics that define bryophytes, ferns, gymnosperms and angiosperms as plants? What key characteristics differentiate each of these groups?

1. Bryophytes: • Bryophytes are known as amphibians of the plant kingdom cause they live in soil but are dependent on water for sexual reproduction. • These plants lack true roots, stem or leaves or they may possess root-like, leaf-like or stem-like structures. Gymnosperms: • Gymnosperms are plants in which the ovules are not enclosed by any ovary wall and they remain exposed both before and after fertilization. • These seeds develop post fertilization and are not covered, hence naked. • The gymnopserms includes medium-sized or tall trees and shrubs. • The gymnosperms are heterosporous and have a sporophyte dominant life cycle while the gametophytes phase is relatively short. Angiosperms: • Angiosperms are flowering plants; they have developed structures called flowers. • The seeds of these plants are enclosed by fruits. • The characteristics of angiosperm include flowers, seeds which contain endosperm and the production of fruits which enclose the seeds. Ferns: • Vascular, reproduce via spores and have neither seeds nor flowers • Have stems and leaves

What is a plant biome and what environmental factors most shape their development? Name five major plant biomes on the earth.

1. Plant Biome ○ a formation of plants that have common characteristics due to similar climates and can be found over a range of continents. Biomes are distinct from habitats, because any biome can comprise a variety of habitats. Environmental factors that shape their development: ○ Temperature- limits: 0°C (freezing point of water) to 45°C (protein denaturation) ○ Water- drought and flooding ○ Sunlight- visible light drives photosynthesis, excess UV light damages cells (like DNA) ○ Wind- accelerates evaporation, accelerates heat loss, influences plant size & structure ○ Soil- pH (5-8 is optimal), Nutrient deficiency (N and P), ion toxicity (Al & Mn) & salinity ○ Disturbance- Fire, volcano, avalanche etc. Five Major Plant Biomes ○ Desert ○ Savanna ○ Tropical forest ○ Grassland ○ Tundra

What factors contribute to the structure and distribution patterns of plant communities?

1. Plant Distribution and density are influenced by: a. Reproductive strategy and success b. Competition for resources c. Resource availability

Outline the three major factors driving human impacts on earth's environments. Using the IPAT formula and the principles found in D&C 104 in the previous slide develop a strategy for increasing human sustainability in earth's ecosystems.

1. The three main factors are a. Population b. Affluence c. Technology If we are to truly be accountable for the things God has given us, we should perhaps become more involved in the process of creating things and sustaining ourselves. We should take the time to learn how to make things for ourselves, such as growing our own gardens. When we spend time in nature coming to know God's creations, we are more in tune with him, and we realize just how involved he is in our lives. This gives us a sense of connectivity and accountability that we don't experience when we are on the consuming end of a system with so many products being made and wasted daily. The Lord has said that the earth is full, but that is only if we take care of it.

Explain the concept of ecological succession and name each of the steps.

2. Ecological succession is when ecosystems undergo a gradual change in the communities they support. There can be a disturbance (such as a fire or a volcano) that resets the system. The steps are as follows: a. Pioneering communities i. First to establish following disturbance b. Transition communities i. Intermediate c. Climax communities i. Final community type that persists until disturbance returns

Identify three specific characteristics that can be used to distinguish pines, firs and spruces.

2. Needle Shape: a. Pines--round cross-section b. Firs--flat c. Spruces--square cross-section Bark Type: a. Pines--rough b. Firs--smooth c. Spruces--rough Cones: a. Pines--woody in nature, with a rigid feel b. Firs--very soft cones, shatter easily c. Spruces--thinner scales than pinecones, which gives them a more flexible feel, papery

What are peatlands and permafrost? Describe the ecological significance of peatlands and permafrost in a warming world.

2. Peatlands: there are 400 billion tons of organic carbon stored in peatlands (resistant to decomposition because of antimicrobial properties of peat). In other words, they produce CO2. Permafrost are areas where the earth is permanently frozen. Right now, this makes up 20% of the earth's land surface. There are 950 billion tons of organic carbon stored in permafrost (formed when plant rich regions froze 40,000 years ago). As this thaws, even more CO2 will be released. Projections are that there will be a 90% thaw by the year 2100. As the earth warms, there will be more drought, and the peatlands will decrease, and therefore release even more CO2 as well.

Describe the steps of pollination and fertilization in a flower.

2. Pollination is the transfer of the pollen from the anther to the stigma. Then, the two immobile sperm cells (male gametophyte) are transferred down the pollen tube. Double Fertilization then occurs when the sperm cells reach the ovule (female gametophyte). One sperm fertilizes the egg, and the other fertilizes two polar nuclei cells (3n) which divides mitotically to form endosperm (embryo food).

What are three traits that allow conifers to effectively deal with drought conditions?

3. Conifers deal with drought by: a. Conserve nutrients by not being forced to produce a new set of leaves every year (smaller leaves) b. Photosynthesize if conditions are harsh to prevent--or delay--new growth (they have green leaves all year round, so they can photosynthesize whenever they want to) c. Wax on the needles is believed to reduce their temperature, as well as transpiration and light absorption. It helps them retain water as well. d. Sunken stomates (deep) help slow water loss e. Tracheids, not vascular tissue

Explain why cross pollination is desirable, identify the metabolic costs associated with it, and outline three strategies plants use to increase the probability of cross pollination.

3. Cross pollination is extremely valuable to plants because it increases their genetic variation, therefore making it more likely for them to survive. However, it does have some metabolic costs: ○ Pollinator attraction § Showy, smelly flowers § Reward: nectar ○ Wind pollination § Copious pollen production Strategies for cross-pollination include: ○ Self-incompatibility § stigma and/or style doesn't allow self-pollen tube growth ○ Dioecious flowering strategy § unisexual flower produced on different plants (he tree, she tree) ○ Male and female flowers and/or organs are developmentally staggered

Describe the anatomy of a fern leaf and explain how relationship between the sporophyte and gametophyte generations differs between ferns and seed plants (gymnosperms and angiosperms).

3. The fern leaf starts out as a young leaf, called a fiddlehead. When the leaf matures, it is called a megaphyll or a frond. On the underside of each leaf, there are many, many sori, each of which is made up of a bunch of sporangium. In Ferns: When the adult sporophytes split from 2N to N and N, the spores don't have a specific gender, they are just different from each other. But when they mature into a gametophyte, one N produces and egg, and the other N a sperm, which are then used in the fertilization process. The only reason they produce a gametophyte is so that they can have something to disperse to use to reproduce. In Angiosperms and Gymnosperms: There are seeds that are used for sexual reproduction. There are male and female gametophytes that are distinct and separate, but the gametophytes are still "supported" by their "parent" sporophyte.

Explain three major reasons why plants produce fruit. What are four ways in which fruits promote seed dispersal?

4. Plants produce fruit: ○ To serve as a fertilizer for germinating seeds ○ To protect the embryo from § Drying out § Pathogens § Herbivores ○ For seed dispersal § Animals (including humans) □ Seeds are discarded □ Seeds are consumed and pass through the gut with a pile of ready-made fertilizer § Wind □ Dandelion § Water □ Coconut

Draw and label all the major anatomical features of a "complete flower".

Complete Flower: sepals, petals, stamens, and carpel [also, see diagram in Ch 6&23, Q 1]

Draw and label the major structures of a seed and describe how each contributes to embryo survival.

Endosperm--food supply Seed coat--protects embryo and controls germination timing Seed--fertilized ovule [also, see diagram in Ch 6&23, Q 2]

How is alternation of generation different in gymnosperms and angiosperms than in ferns?

In the Gymnosperms and Angiosperms, the gametophyte generation is dependent on the Sporophyte generation (parents), whereas in the ferns, it is not. [see diagrams in Ch 22, Q 1]

Fill in the table below. For the temperature and precipitation ranges use the words in the parentheses; if there is broad range use two terms linked with a hyphen (e.g. cold-moderate)

SEE TERMS LIST FOR: Tropical Forests Savannas Grasslands Deserts Chapparal Temperate Deciduous Forests Coniferous Forests Tundra

Much of ecosystem function is defined by interaction among organism; define the following terms related to how organisms interact: commensalism, mutualism, parasitism and competition.

a. Commensalism i. Interaction between two species where one benefits and the other is unaffected (ex. Epiphyte) b. Mutualism i. Interaction between two species in which both organisms benefit 1) Plant and bacteria associations (nitrogen cycling, nitrogen fixation) 2) Mycorrhizas 3) Plants and insects (acacia and ants pollination) c. Parasitism i. Association where one organism benefits at the expense of the other organism d. Competition i. When two species live in the same area and need the same resources, one will end up being reduced or eliminated

Name five major ways that we impact our environment and what can be done to reverse those effects?

a. We cut down photosynthesizing plants to make room for factories and animal feeding areas that create more CO2 instead of reducing it. i. We could make a point to plant a tree for every one we cut down. b. We pollute the air by using toxic chemicals as fuel or in the factories we run. i. We could use other forms of energy, such as hydraulics or even windmills. c. We are using up our water supplies quickly. i. We can find more ways to catch rainfall and purify it instead of taking up water strictly from underground. d. Water pollution is also a huge problem. i. We could impose fines on individuals and businesses that dump waste into water. We could also make it much easier for people to recycle their waste. e. Planned obsolescence is another problem. Products are designed to go out of date or stop working within a short timeframe. i. We could fine individuals and companies that do this intentionally. Some of this has already begun with cell phone chargers. It is now required that all android cell phones have the same charger so that we don't throw away the old ones when our phone needs replacing.

Describe the floral anatomy that produces simple, multiple and aggregate fruits? What are the two major classes of dry fruits and what defines their differences?

○ Simple Fruit--develop from a single carpel in a single flower (cherry) ○ Aggregate Fruit--develop form one flower with many carpels (blackberry) ○ Multiple Fruit--develop from multiple flowers (pineapple) Dry Fruits ○ Dehiscent--split open at maturity to shed seeds ○ Indehiscent--remain closed at maturity

Describe four different strategies that flowers employ to attract pollinators.

○ Smells ○ Nectar rewards ○ Color ○ Sexual deception

Describe the three different methods of pollinator deception and explain its risks and rewards to plant fitness.

○ Visual- flower appears like nectar providing flower but has no nectar ○ Chemical- flowers produce female pollination phermones ○ Visual sexual- flower visually and anatomically looks similar to female fly Risks: ○ If they kill off their pollinators completely, the plant will also die Rewards: They can attract pollinators without actually giving anything up