Dr. FisherDr. Fisher

Biology 156 – Plant BiologyBiology 156 – Plant Biology

From Baram-Tsabari et al. 2010

From Baram-Tsabari et al. 2010

Learning Goals – By the end of this course, you will:

• Appreciate the importance of plants in your daily life

Learning Goals – By the end of this course, you will:

• Appreciate the importance of plants in your daily life

• Have a better understanding of plant diversity and evolution in general

Learning Goals – By the end of this course, you will:

• Appreciate the importance of plants in your daily life

• Have a better understanding of plant diversity and evolution in general

• Appreciate the connections between plant ecology, biodiversity, and human culture

Learning Goals – By the end of this course, you will:

• Appreciate the importance of plants in your daily life

• Have a better understanding of plant diversity and evolution in general

• Appreciate the connections between plant ecology, biodiversity, and human culture

• Gain a deeper understanding of the process of science and evidence based inquiry

Why Care?

• You don’t need to be a scientist to think like a scientist– approaching this course scientifically will help

your learning!– we need more scientifically literate citizens!

• Life as we know it (or anything close) could not exist without plants– being alive requires energy

Learning Outcomes

By the end of today, you will be able to:

• Explain the basic objectives of science• Describe the typical structure of scientific

methods• Evaluate the importance of photosynthesis for the

biosphere

What is science?

What is science?• Inquiry – being curious!• Evaluating evidence to answer questions about

the natural world• An ongoing process – new evidence is considered

and old ideas are revised to include our most current understanding

• A very human endeavor – science is a community effort, and requires both collaboration and dissenting opinions for its advancement

Why Understand Science?

• “What strikes one immediately upon reading such a statement is the low estimate of the Bible which it entails. Whenever ‘science’ and the Bible are in conflict, it is always the Bible that, in one manner or another, must give way. We are not told that ‘science’ should correct its answers in light of Scripture. Always it is the other way around. Yet this is really surprising, for the answers which scientists have provided have frequently changed with the passing of time. the ‘authoritative’ answers of pre-Copernican scientists are no longer acceptable; nor, for that matter, are many of the views of twenty-five years ago.”

-Young, E.J. Days of Genesis. Westminster Theological Journal 25(1):1–34.

Typical Scientific Process

• Observation• Question• Formal hypothesis (“If, then...If not, then...”)• Gather data / evidence• Evaluate

The First Recorded Experiment in Plant Biology

• Run by Jean Baptista van Helmont in 1684

• Observation – plants grow, but they don’t appear to eat like animals. Where does the matter that makes up plants come from?

With your neighbor:

• Formulate a hypothesis to explain this observation

• What additional information do you need to test this hypothesis?

Van Helmont’s Experiment

200 lb dried dirt5 lb baby willow tree

5 years

?

Van Helmont’s Experiment

200 lb dried dirt5 lb baby willow tree

5 years

199 lb, 12 oz dried dirt169 lb willow tree

Van Helmont’s Experiment

• Van Helmont concluded that the willow tree’s biomass must have come from the water he gave the tree (not the soil)

• Was his conclusion correct?

Joseph Priestly’s Experiment – 1770s

What did this experiment demonstrate?

Jan Ingenhousz’s Experiment - 1779

What happened in the dark?

What we know today: Photosynthesis

• Plants convert electromagnetic energy from sunlight into chemical energy (chemical bonds in ATP)

• They use this chemical energy to build sugars from carbon dioxide (in the air) and water

Photosynthesis & the Carbon Cycle

Why we owe our existence to photosynthesis

• We require energy to live• We are carbon-based life forms• We cannot assimilate carbon from the air, nor can

we capture energy from sunlight

....So, we need to EAT things to break down for our energy and carbon