Concepts of Biology II – 03-55-101-01

Class time: 4:00 – 4:50 PM Tuesday & ThursdayPlace: 1120 Erie Hall (but you’re here, so you know that)

Professor: Mike WeisOffice: Room 202 Biology BuildingPhone: 253-3000 ext.2724Email: mweis@uwindsor.ca

Office hours: Tuesday & Thursday 12:00 – 2:00 PM (or by appointment)

Exams and Grading:2 midterms during class hours and a final.

Midterm 1 Feb.10 25% of markMidterm 2 March 22 25% of markFinal April 25 noon 50% of mark

Exams will consist of (mostly) the various forms of short answer questions (multiple choice, fill-in-the-blank, matching, etc.) with a few questions requiring written answers of no more than 1 or 2 sentences.

Midterms cover segments; the final is comprehensive.

Scheduling conflicts concerning exams must be reported to me at the earliest possible date, and under no circumstances less than two weeks prior to the exam.

Grades are non-negotiable. Mechanical errors in grading will be rectified (i.e. addition errors)

There will be zero tolerance for cheating. Clear evidence of cheating will be prosecuted to the full extent allowed by university policies.

Here is a tentative schedule of lecture subjects:1) Introduction to the courseEvolution:1) Brief review of MendelianGenetics2) Evidence of evolution3) Population genetics and microevolution4) Macroevolution: the evolution of speciesEcology: 1) The Biosphere and the Biomes2) Population Biology3) Community Ecology4) Ecosystem Ecology5) Behavioural Ecology

6) Conservation Biology7) Applications of EcologyPlant Anatomy & Physiology13) Plant structure and transportAnimal Anatomy and Physiology14) Circulatory System 18) The Senses15) Immunity 19) Endocrine System16) Excretory System 20) Human

Reproduction17) Nervous System 21) Muscular System

This schedule is subject to modification (time limits may cause one or more subjects to be dropped), and may be adjusted to allow for guest speakers.

Living organisms:-are highly ordered-reproduce (life originates from life)-grow & develop (driven by heritable programs)-utilize energy (take in and transform energy)-respond to their environment-regulate their internal environment -evolve (i.e, change in response to interactions between organisms and environment) at the population level

Biology is the study of life. To know what we’re going to study, we’d better begin with a ‘definition’ of life (the universal properties of living things):

Cells are living things’ basic units of structure& function:

- all living things have an inside/outside boundary, i.e. membranes that regulate passage of materials between the cell & its environment

- the cell is lowest level of structure capable of performing all activities of life

- all organisms are composed of cells, whether unicellular or multicellular organisms

- all cells contain DNA at some stage

The Diversity of Life is categorized into 3 domains:Two Prokaryotic domains –

the Bacteria and the Archaea

They have in common the lack of a membrane-bound nucleus and the lack of organelles

within the cells. They are generally unicellular.

One Eukaryotic domain – protists (algae, amoeba, and many others),

fungi, plantae, and animalia

They have membrane-bound nuclei & internal organelles. Some protists are unicellular;

others & the other groups are multicellular.

The Continuity of Life is Based on Heritable Information in the form of DNA

-Watson/Crick double stranded DNA: a linear sequence of four nucleotides arranged in genes

-biological structure and function is encoded in genes, the unit of inheritance

-inheritance based on complex mechanisms to: a) copy DNA b) distribute DNA between parent and offspring

-all life forms use essentially the same genetic code; diversity arises from different DNA sequences

Similarities among all living things is best explained by EVOLUTION:

It is the one unifying theme in Biology

-species change; contemporary species arise from a succession of ancestors through a process of “descent with modification” (Darwin)

-a (and likely the most important) mechanism of evolutionary change is natural selection

- a way to understand why natural selection is so important: “adapt or die”- adaptation provides the potential to survive & reproduce in a given environment

Scientists study life in two ways:

1)By observation (what the text calls “Discovery Science”, and what is elsewhere called descriptive

science)

Conclusions can be drawn from observation only by means of induction. If we see the same thing enough times, we begin to believe it is true. We draw general principles from large numbers of specific observations.

-- Or --

2) By using the hypetheco-deductive method (which we usually call ‘The Scientific Method”). This method begins with an observation. The scientist then proposes and explanation for the observation – the hypothesis – and designs experiments to test his/her proposed explanation.

The process uses deductive reasoning. The test makes (draws) an inference (a prediction) from general premises (the proposed explanation) to specific consequences, which logically follow if the premise is true. The process is “If…then logic”

A useful hypothesis must be testable by hypothetico-deductive method. Testable here can be taken to mean that the hypothesis can be (potentially) falsified by tests.

If falsified, the hypothesis can be eliminated or (at least) modified. But it can never be completely proved.

When scientists have tried enough tests to believe that the hypothesis is very unlikely ever to be disproved, it is elevated to the status of theory.

The Hypotheco-Deductive Method:

How does the method work?

A well designed experiment has a control group (one in which nothing is changed from the norm) and one or more experimental groups, in each of which a single variable is modified.

Note the underlined word ‘group’. Replication is critical in science. Results of many (probably most) experiments are examined statistically. A significant result (meaning the variable you modified is important) is a difference between experimental and control groups that would occur by chance alone less than once in 20 tries.

It is the prediction you made from your hypothesis that determines what variable you modify for your experimental group.

An example should clarify this:

In the British Museum is a long history of collections of a moth called the peppered moth. Up until around 1700, moths were predominantly ‘peppered’, i.e. whitish with mottled dark spots. There were a few % that were dark coloured.

By 1850, moths were predominantly dark coloured, with only a few % of the peppered type.

Around 1850, a British entomologist named J.W. Tutt suggested that bird predators picked off peppered moths from trees based on the contrast between their coloring and the color of tree bark.Logical, but was this hypothesis scientifically correct?

In the 1950s, Bernard Kettlewell tested the hypothesis in a controlled experiment. He grew both peppered moths and a dark (melanistic) morph of this species in the lab, then released them in two forested areas.

The two areas were:

A) in areas near Birmingham polluted over more than two centuries since the beginning of the industrial revolution. There the bark of trees was blackened by soot.

and

B) in unpolluted areas of Dorset. There the bark of trees was pale.

The difference should (logically) favor dark moths near Birmingham, and peppered moths in Dorset.

Birds are visual predators; they capture moths during the day, while the moths rest on tree trunks.

To ensure he wasn’t confusing his released moths with natural populations, he marked each released moth with a spot under the wing, where birds couldn’t see it.

He set traps to catch the moths, and could determine the number of each morph (dark vs. peppered) predated in each environment.

Here are the fractions he re-captured:

peppered darkNear Birmingham 19% 40%In Dorset 12.5% 6%

Kettlewell went one step further. He set up blinds in both areas and filmed birds ‘choosing’ moths to eat. The birds chose the ones that were most clearly visible.

The effect on the evolution of moth pigmentation frequency is called industrial melanism.

Here are the moths against the two backgrounds:

In Dorset

Near Birmingham

Finally, let’s look at Kettlewell’s work – what are the experiments? Were there proper controls?

There were two experiment(s), replicated in each locale. Control groups were more cryptic (blended with the background) moths predicted to be less predated; experimental groups are more contrasted.

In Dorset, without heavy pollution, the peppered morph is the control. Was the percentage recaptured similar for control and experimental groups?

Control: 12.5% Experimental: 6%In Birmingham the groups are reversed. Dark morphs are the controls.

Control: 40% Experimental: 19%

In both places, it turned out that there were significant differences in the percentage of released moths recovered, and other evidence (observations from blinds) that the reason was bird predation.