Biology Test 3 Flashcards
Define Land Plants
Descended from a single group of green algae/multi-cellular eukaryotes with reproductive organisms
Relationship between Green and Red Algae, Dinoflagellates and Land Plants
Green Algae is the closest relative to land plants. They all began eons ago by acquiring the chloroplasts from engulfing cyanobacteria
Major Clades and their adaptations
Charophytes- Water plants
Bryophytes- Non-Vascular Land - cuticle/stomata
Lycophytes- cuticle, stomata, vascular tissue
Angio-Sperms- flowers, fruit, pollen, seeds
Gymno-Sperms- pollen, seeds, vascular tissue, cuticle, stomata
Describe what cuticle and stomata are, why they are adaptive, and how they function in land plants.
Cuticle-cover leaves to minimize rate of evaporation allowing plants to retain more water
Stomata-on the underside of leaves, open to let oxygen and carbon in and out of plants while they close to minimize water loss
Describe vascular tissue – including cellulose and lignin – why it is adaptive and how it functions in land plants
Vascular tissue is basically used to transfer water and nutrients throughout the plants. It is adaptive because the plants can only get nutrients from the ground but in order to grow the plant needs to produce xylem and phloem to transport nutrients from the roots to the tops of the plants. Lignin binds cellulose together on the cell wall and is the secondary wall behind the cell wall
Read/Think about seeds, pollen, flowers, and fruit. Given what you learn, describe why they are adaptive in land plants.
In land plants, seeds, pollen and flowers are all ways for reproduction and dispersal. They are adaptive in land plants because they have to find way to be transferred in order to continue their speciation. Flowers, pollen and seeds are relatively new adaptations compared to cuticle and stomata. These adaptations are found in the gymnosperms and angiosperms
Why does the adaptive value of a trait have to be tested and how do we test it?
Hypotheses can be tested by using them to make predictions, then checking to see if the predictions are correct by using experiments, observations, and through comparative methods.
The adaptive value of a trait must be tested because you should never rely on an explanation just because it is plausible and charming. It must be tested so we can confirm or deny the hypothesis and learn how the trait really evolved.
- Explain the Delph and Lively research on Fuschia excorticata, including a correct and complete response to the question posed during class. Given data that is new to you, analyze those data and evaluate hypotheses about evolution.
The Fuschia excorticata flower faces down and starts off green, but then turns red and the pollinators, bellbirds, visit the flower when it is green, which is odd because birds prefer to visit species with red flowers. So why then did this bird-pollinated species evolve green flowers? Also, why does the tree keep its flowers after pollination instead of just dropping them.
(I’m inserting the slides so you get all the information)
Hypothesis 1 Pollinator Attraction: Red flowers may still attract pollinators to the tree displaying them. Once drawn to the tree, pollinators could forage on the green flowers still present on the tree. Thus, retention of the red flowers could increase the overall pollination efficiency of the individual tree retaining them.
Prediction: Green flowers surrounded by red flowers should receive more pollen than green flowers not surrounded.
Test: Remove red flowers from some trees but not others, and from some branches within trees but not others. Compare the amount of pollen deposited on green flowers in red-free trees and branches versus red-retaining trees and branches.
Result: No significant differences. Hypothesis rejected.
- Know the nine macronutrients that are essential elements for plants – carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, calcium, potassium, and magnesium. Draw a diagram of a plant that shows where different macronutrients come from.
Carbon, oxygen, and hydrogen are obtained from air or water and the rest of the macronutrients and micronutrients must be absorbed from the soil.
- Describe the types of interspecific interactions peanut plants have in their soil and recognize that other plants have similar types of interspecific interactions.
Fungi- Apergillus flavus and aspergillus parasiticus infect peanuts; produce aflatoxins shown to be carcinogenic
Animals- lesser cornstalk borer: Larvae feed on roots and developing pods. Millipedes: feed on seedling plants and developing pods.
Bacteria and Archaea: 1-4 billion bacteria per tsp of soil. Most are helpful; rhizobia.
- Explain the role of root nodules in legumes and how nitrogen-fixing bacteria infect a plant.
Root nodule bacteria convert atmospheric nitrogen (N2) to ammonia (NH4+). N2 cannot be used by plants, but NH4+ can.
Mutualistic relationship: peanuts gain nitrogen; rhizobia bacteria gain sugars and hemoglobin (oxygen for cellular respiration)
Nitrogen-fixing bacteria infect a plant:
Root hairs release a chemical signal that attracts rhizobia. Rhizobia move into hairs.
Chemical signal: Plant secondary metabolites
Rhizobia proliferate inside root hair and cause an infection thread to form.
Infection thread grows into the cortex of the root.
Infection thread bursts, releasing rhizobia inside cortex cells.
Nodule forms from rapidly dividing cortex cells.
- Explain the three ways plants obtain nitrogen: from free-living bacteria, assisted by mycorrhizal fungi, or from Rhizobial bacteria.
Free- living bacteria: bacteria in the soil that is converted into: ammonium, nitrites, and nitrates
Mycorrhizal fungi: spreads bacteria through the soil
Rhizobial bacteria: located in root nodules of legumes and converts atmospheric nitrogen into ammonia.
- Explain how plants use the metabolites that humans also use.
Plants use secondary metabolites in defense against herbivores, prevention of infection by pathogens, and protection from environmental stressors such as drought, UV radiation, and high temperatures.
Humans use plant secondary metabolites for spices, dyes, and medicines.
Both plants and humans use tannins, which are compounds that are stored in the vacuoles of plant cells in bark and leaves.
For plants, tannins protect the bark and tissue from infection by pathogens.
For humans, tannins give the bitter or tart flavor found in tea and wine.
- Describe some research questions an ethnobotanist would investigate.
What plants are used by a given group of people?
What ailments are the plants used to treat?
How are the plants used?
How the culture views plant in folklore, symbols, and ceremony?
- Explain how to design a study involving clinical trials, including the use of a control group, the purpose of randomization and how it is insured, and the use of blind testing.
Stages of research: First, researchers gather data from communities who traditionally used the plant and learn about is medicinal use. Second, they identify and isolate the compound that acts as the active ingredient. Third, the active ingredient is tested on animal subjects to determine its effectiveness and side effects that may be too dangerous for human testing. To perform animal testing, researchers must obtain appropriate permits to ensure proper handling and safety. Fourth, human subjects are tested.
The researchers identify a hypothesis to test.
A placebo serves as a control, which is a standard for comparing the treatment and to assure no other variables exist.
Randomization is used to get accurate results and prevent any bias or potential lurking variables. Participants are randomly assigned to the two groups, one group receiving the placebo and the other receiving the treatment.
Blind testing: participants are not told if they are receiving the treatment or placebo. This is to ensure that there is no bias. In a double-blind study, neither the participants nor researchers know who is taking the treatment or placebo.
- Explain the concepts of mean, standard deviation, and probability as they pertain to scientific investigation.Interpret quantitative data using means, standard deviations, and probability measures, and draw conclusions from those data.
Mean: average value of the group or population
Standard Deviation: how far spread out the individual values are from the mean
Small standard deviation means similar means (or values)
Large standard deviation means very different means (or values)
Probability: how likely the outcome of an experiment is due to chance; reported as the p-value.
P-value= 5% or lower- there is a significant difference between two means (or values)
P-value= greater than 5%- there is not a significant difference between two means (or values) and difference is due to chance.
- Answer the following questions for both Kava and St. John’s wort: What category of land plants do they belong to? Are they native to the U.S.? How long have humans used the plant for medicine?
Kava: Angiosperm, Native to South Pacific Islands
St. John’s Wort: Angiosperm, native to Greece (Europe)
the nine macronutrients that are essential elements for plants
carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, calcium, potassium, and magnesium.
Describe the types of interspecific interactions peanut plants have in their soil and recognize that other plants have similar types of interspecific interactions.
- The peanuts have many different types of interactions that occur in the soil. There is predation (Millipedes feeding), commercialism (food for larvae), and even mutualism (the bacteria).
- The bacteria gain sugars and hemoglobin that aids in respiration and the bacteria convert nitrogen into a usable form for the plant (nitrogenase).
Explain the role of root nodules in legumes and how nitrogen-fixing bacteria infect a plant.
Root nodule bacteria convert atmospheric nitrogen (N2) to ammonia (NH4+). N2 cannot be used by plants, but NH4+ can.
2. The root hairs release a chemical that attract the bacteria. The bacteria enter and multiply inside the root hair, and then move into the cortex of the root. They then form a nodule that allows the bacteria to rapidly reproduce and create the nodule.
Explain the three ways plants obtain nitrogen: from free-living bacteria, assisted by mycorrhizal fungi, or from Rhizobial bacteria.
From Rhizobia: the bacteria lives inside the root itself and takes in nitrogen from the soil and converts it to ammonia, which is usable by the plant. (Mutualistic)
Explain how plants use the metabolites that humans also use.
Many plants produce “secondary metabolites” that serve no use in respiration or key functions that can produce many beneficial effects. If animals or humans ingest these plants they can experience these effects. Some can be beneficial while some can be deadly. The plants use these metabolites in inter-specific relations (Ex. Attracting mutualistic organisms or protection).
Describe some research questions an ethnobotanist would investigate.
They might investigate an indigenous peoples’ relationship with a certain herb and what they use it for. They aim to see how people use the plants, their effects, and how this differs among different societies.
Explain how to design a study involving clinical trials, including the use of a control group, the purpose of randomization and how it is insured, and the use of blind testing.
- When conducting a clinical trial, it’s important to use randomization to insure that the results aren’t skewed by any unseen factors. This can be done with various techniques such as a random number table.
- Blind testing is a process in which the test subjects don’t know if they are in the control group (placebo group) or the treatment group. This helps keep the test as unbiased as possible. To even further prevent bias, a double blind test can be conducted.
