Note
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BioL 102 - Botany (Lecture notes)
CHAPTER 1:Introduction to Plants and Botany
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Concepts
• Carbon dioxide is a greenhouse gas.
• Plants lock carbon dioxide in their tissues.
• This counteracts some of the heating effects of carbon dioxide.
• Plants changed the climate of Earth in ways that we can now live on it.
• Plants also produce the oxygen we breathe and the food we eat.
• We get cloth, paper, lumber, and chemicals from plants, and plants are important to us spiritually because of their beauty.
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Plants: A Solution to Global Climate Change?
• Accumulation of atmospheric CO2 is responsible for changing global climate.
• Plants remove atmospheric CO2 during photosynthesis.
• Plants have changed Earth’s climate.
• Can plants reverse the accumulation?
– Release of CO2 outstrips assimilation.
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Plants
Botany is the scientific study of plants.
Defining the term plant is difficult.
- Inclusion or exclusion of some groups.
- Biologists do not all agree.
Algae: Are they plants?
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Most have green leaves, stems, roots, and flowers, though there are exceptions.
Conifers (gymnosperms) don’t produce flowers.
Mosses lack true leaves, stems, and roots and neither mosses or ferns produce flowers.
Fungi were once considered plants but are now excluded.
Green algae are problematic.
Similar to plant at the cellular and biochemical level
But seem to share more with other algae
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History of Explanatory Methods
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• Until the 15th century, religion and speculative philosophy were important explanatory methods.
Religion
- Religions generally say the universe was
created by or contains deities. - The actions of gods cannot be studied.
- Knowledge comes from the gods.
- Faith without proof is required.
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Speculative philosophy
- Was developed by ancient Greek philosophers.
- Involves developing logical explanations for simple observations of the world.
- Does not involve any verification of truth. o Only predictions were made without experimentation.
- Is problematic because several conclusions may be equally logical and plausible.
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The scientific method slowly developed starting before the 1400s, with four basic tenets.
- Source of information
- Phenomena that can be studied
- Constancy and universality
- Based on skepticism
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- ==Source of information==
Information must be derived only from carefully documented and controlled observations or experiments.
Any claim must be subject to verification and proof.
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- ==Phenomena that can be studied==
- Only tangible phenomena and observations may be studied.
- Anything that cannot be observed (or detected by an instrument) cannot be studied.
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- ==Constancy and universality==
- Physical forces that control the world are constant through time and the same everywhere. Experiments done at one place and time should give the same results if carefully repeated at a different time and place.
- Constancy and universality allow us to plan future experiments and predict what the outcome should be.
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- ==Basis—Skepticism==
- The fundamental basis of the scientific method is skepticism.
- Skepticism is never being certain of a conclusion and of always being willing to consider new evidence.
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The form of a scientific study follows this basic sequence:
- A series of observations
- A period of experimentation
- Further observation and analysis
- Construction of a hypothesis, or model
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- A ==hypothesis== must make predictions that can be tested.
- It must be consistent with further observations and experiments. − It must be able to predict the results of future experiments.
- A ==theory== develops from a hypothesis that consistently matches observations and garners greater confidence.
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Intelligent Design
The concept that many structures and metabolisms are too complicated to have resulted from evolution and natural selection and therefore must have been created.
This concept does not help us to analyze or understand the world around us.
− It is used as an answer in itself, which prevents any further study.
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Areas Where the Scientific Method Is Inappropriate
• Science can:
− Study, measure, analyze, and describe the factors that cause people to kill each other or to be racist or sexist.
− Predict the outcome of these actions.
• However, science cannot say whether such actions are right or wrong, moral or immoral.
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Using Concepts to Understand Plants
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1.Plant metabolism is based on the principles of chemistry and physics.
2. Plants must have a means of storing and using information.
Genes are the primary means of storing this information.
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3. Plants reproduce, passing their genes and information on to their descendants. – Seeds contain information from their parents.
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4. Genes, and the information they contain, can change.
– Plants copy genes during reproduction.
– These changes cause differences in offspring.
– Over time, a gradual evolution occurs.
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5. Plants must survive in their own environment.
– They must be adapted to their environment.
– Plants more suited to their environment reproduce more successfully and produce more offspring.
– The presence of other organisms may be detrimental, beneficial, or neutral.
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6. Plants are highly integrated organisms.
– The structure and metabolism of one part tend to impact the rest of the plant.
– An adaptation in one area is often balanced by changes in another.
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- An individual plant is the temporary result of the interaction of genes and environment.
– The way a plant interacts with its environment is guided by genetic information that has slowly evolved over thousands of years.
– The genetic pool of the species exists beyond the phenotype represented by a single specimen.
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- Plants do not have purpose or decision-making capacity.
– Anthropomorphism and teleology should be avoided.
o Anthropomorphism: applying human characteristics to non-human organisms or things
o Teleology: the assumption that processes or structures have a purpose
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Origin and Evolution of Plants
• Organisms were originally simple and increased in complexity through evolution by natural selection.
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Natural Selection
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