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ECOL 182 (Spring) Intoductory Biology - Study Guide

I've written this after having completed the questions for the exam, and while looking at the lecture notes - this is a guide for studying, not necessarily a content list that you should memorize.

Lecture 1 - Evolution of photoautotrophy

The goal of this lecture was to provide you with 'a modern view' of photosynthesis, including: (1) where did it come from? (2) what is the primary stucture? (3) what does variation in the structure mean? (4) where are physiological processes controlled?, and (5) how does the system integrate into a plant.

We discussed such issues as:

1. The nature of light (particle versus wave properties)
2. When photosynthesis likely evolved and it's distribution in lifes clades
3. Where oxygenation abilities evolved
4. The universal photosynthetic structure, including important variation on the theme (Halobacteria, etc)
5. The 'problem' of chlorophyll biosynthesis
6. The relationship of chloroplasts and mitochondria to prokaryotes and eukaryotes
7. The relationship between the Calvin Cycle and the Light Reactions (processes in the Universal Photosynthetic Structure), including the concept of "sink" control over rates of photosynthesis.
8. The energetic requirements in the Calvin Cycle (does Rubisco activity need energy?)

Lecture 2 - Evolution and diversity in plants (I)

The goal of this lecture was to introduce you to the initial variation in the most ancient groups of plants and contrast groups as we moved through the evolutionary tree. We started with talking about how plants have special features that maintain or add variation in a population (Fisher's fundamental theorem of evolution by natural selection). We ended by discussing the synapomorphies and important evolutionary innovation through time for different clades.

We discussed such issues as:

1. What is a plant?
2. What is an embryophyte and how is it different from algae?
3. What is a tracheophyte (versus a non-tracheophyte)?
4. What is the alteration of generations that is important in embryophytes?
5. What are characteristics that allow for invasion of the land?
6. How do ancient plants move resources around their bodies?
7. When did stomata evolve?
8. What is the difference between phloem and xylem?

Lecture 3 - Evolution and diversity in plants (II)

The goal of this lecture was to continue with the description of the variation in the more derived groups of plants and contrast groups as we moved through the evolutionary tree. Important contrasts here included differences between non-seed and seed plants, and differences between gymnosperms and angiosperms. We also talked about evolutionary trends across all groups (such as the relationship between sporophytes and gametophytes).

We discussed such issues as:

1. Differences between heterosporous and homosporous plants
2. The definition of a 'seed'
3. The characteristics (morphological and physiological) associated with the production of secondary growth
4. The arrangement of xylem trachieds and sieve tube elements (in gymnosperms)

Lecture 4 - Plant structure and function (I)

In this lecture we finished talking about the Angiosperms and started discussing how plants function. Much of this was in the context of the unique characteristics of the Angiosperms (as compared to Gymnosperms and other groups). We spent a whole lot of time talking about how water moves in plants.

We discussed such issues as:

1. The differences between trachieds and vessel elements
2. Changes in phloem in Angiosperms
3. Synapomorphies of Angiosperms (including Monocots and Eudicots)
4. How water moves in plants as a function of variation in solute and pressure potentials (between cells and within whole plants and to the atmosphere)
5. The role of stomata in controlling the evaporative loss of water and balancing carbon dioxide uptake.
6. How when substantial tension develops, a break-down of the continuous stream of water from the roots to the shoots, leaves and atmosphere occurs. This constrains where plants can grow.

Lecture 5 - Plant structure and function (II)

In this lecture, we picked up on the topic of cavitation, and important differences between plants groups (angiosperms, gymnosperms) and plants with different vascular characteristics (trachieds, vessel elements, pit densities). I introduced the concept of 'safety margins', that illustrated how risky plants behave as a function of their environment. We then began a discussion of how plants grow, and what constrains their maximal height. We discussed then, at length, how substances move in the xylem and phloem, before we began discussing nutrients.

We discussed such issues as:

1. Dessication induced cavitation versus freez-thaw induced cavitation (and their interaction).
2. The importance of the maintenance of turgor for growth (cells grow by maintaining positive pressure that can expand cell walls)
3. How gravity influences the components of water potential
4. The pressure flow model of transport (interactions between xylem and phloem)
5. Where are nutrients located, and where do most come from in terrestrial ecosystems?

Lecture 6 - Plant functional types: evolutionary responses to environmental challenges

The goal of this lecture was to move from a view of plants operating in isolation from their enviroment, to a view of them interacting with their environment - nutrient dynamics highlights this interaction. Nutrient availability, uptake and return, all demonsrate the way that function in most plants depends on plant characteristics, environmental characteristics and their interactions (for example, the relationship between plant functional type dominance and the 'return' of resources to the soil). We also began discussing important evolutionary innovations - such as C4 and CAM photosynthesis.

We discussed such issues as:

1. Where do most nutrients come from in terrestrial ecosystems?
2. What is the big deal about the observation that there is high nutrient availability in mineral and organic forms compared to the rather low nutrient concentration in the soil solution?
3. What environments would have low nutrient avaialbility and why?
4. What is the difference between mass flow and diffusion?
5. What kinds of ways have plants evolved for dealing with low nutrient availability (e.g., symbiosys, etc.)
6. How do plants respond in an integrated manner to changes in nutrient availability? (recall the flow chart I showed)
7. How do differences in plant strategies interact with nutrient availability? (especially nutrient return to the soil)
8. What important characteristics of Rubisco have led to novel photosynthetic innovation?
9. What are the simple descriptions of CAM and C4 photosynthesis
10. What are the implications of CAM and C4 photosynthesis for nutrient, light, and water use?