Wk 12, Looking Ahead to Wk 13

Wk 12

First, I will once again give my apologies for not being in class this week.  It was our last week on evolution, and I had recent non-professional scientific articles on evolutionary topics to read and discuss.  I hope that you make the extra effort to complete the readings and videos from this week in order to solidify your understanding of the evidences we have for the theory of evolution.

Ecology

This is my favorite topic in biology! I am very excited for these last three weeks!

We are already familiar with levels of organization which begin with the atom and end with the organism, such as the diagram below.  

But that isn't the end! Ecology is the area of biology which studies organisms and their interaction with their physical environment.  There are levels of organization in ecology, as shown in the diagram below.

• An individual is one organism during its lifetime (example a male elk born in Spring 2011, identified by a distinct golden streak on his neck)
• A population is a group of organisms of the same species all living in the same geographic area at the same time (example a heard of elk in the Western Cascades montane*)
• A community is all the different populations that live together in the same geographic area (example all the elk, fir trees, moose, rabbits, lupine flowers, owls, bears, and beavers of the Western Cascades montane)
• An ecosystem is all of the living (biotic) and non-living (abiotic) factors that interact in the same geographic area (the community of the Western Cascade montane as well as its mountain streams, leached soils, short summer, limited sun exposure on the north face of the mountain, glacier activity, and volcanic activity)
• A biome is one of the world's major communities (in large geographic areas), classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment (example Temperate Forests)
• The biosphere is global ecological system, including all the living organisms and their relationships to their physical environment (example Earth)

* montane is a mountain forest ecosystem 

Ecologists study the organisms at each of these levels (the living things are the biotic factors), as well as their interactions with each other and with the non-living portion (abiotic factors) of their surroundings.  

• Biotic factors include animals, plants, fungi, protists, and bacteria - all living things in the ecosystem.
• Abiotic factors include water, sunlight, temperature, soil, wind, and chemicals in the atmosphere (as well as other factors).

These abiotic factors aren't static either, they change over time.  The earth is composed of many cycles and systems - carbon cycle, water cycle, weather systems, rock cycle, etc - and is quite dynamic.  More on the cycles in the coming weeks.

So we have these different levels of organization, both biotic and abiotic factors, and what we are really looking at are all the relationships that are going on. That's what ecology is really about: interaction.

Readings and Other Resources

Since each of the texts approach ecology in different orders, I have simply divided up the ecology sections into three weeks of reading.  The order in which your text covers these topics will be slightly different, but by the end we will have all covered the same things.

13 Ecology I

RSO Ch. 24 The Biosphere

LOE ch 37-38

CK12 BC 6.1-6.10

Ck12 LSC 12.1-12.11

Biological Levels: The World Tour - transition, Amoeba Sisters covers levels of biological organization Introduction to Ecology - Teacher's Pet overviews the definition of ecology and important terms of the levels of study in ecology Ecology - Rules for Living on Earth - CrashCourse covers what ecology is and the levels of study in ecology

End of the year is approaching quickly - don't forget all the things for Biology class:

• Readings and videos for this week
• Battle of the Beaks lab due this Thursday
• Bring your vocabulary list to class and choose which sticker you would like this Thursday
• Monster Book Discussion and Movie on this Saturday the 30th and my house

Wk 11, Looking Ahead to wk 12

Battle of the Beaks

This week in class we simulated the pressure of natural selection.  We had a variety of bird "beaks" (everything from chop sticks to binder clips), all of which were competing for different food varieties (white bean "beetles", elastic band "worms, etc).  Some beaks were proficient at picking up one food type and getting into their paper cup stomach, while other beaks were better suited for other food types.  And some beaks had a rough go no matter the food type.

These different beaks represent different genetic traits in a population of birds.  Those birds with the best-suited beak for the available food would live longer and therefore have the opportunity to reproduce more often.  Less successful birds, with less energy acquired through feeding, would be more vulnerable to prey or hard conditions and not live as long, and reproduce less often.  Thus, there would be a shift in the frequency of the genes in the population (we call this microevolution), with the genes of the first bird increasing and the genes of the second bird decreasing.

If this slow, incremental change continues over a very long period of time (remember our very long timescale of the history of the earth), the cumulative difference can be quite significant.  Think about dinosaurs evolving into birds.  We call this macroevolution.

Looking Ahead to wk 12

The weeks are ticking away! This week is about the evidences for evolution.  While evolutionary theory is not bullet proof, it has a great deal of evidence supporting it.  Because of the limitation of time, we cannot do controlled experiments for macroevolution.  We can, however, study the evidences.  These evidences fall into 4 major categories:

1. Fossil Evidence - this includes relative dating and radiometric dating, among others
2. Comparative Anatomy Evidence - this includes studying embryology and development, homologous structures, analogous (homoplastic) structures, and vestigial structures, among others
3. Biogeography Evidence - historical distributions or organisms and the correlation to plate tectonics
4. Molecular Biology Evidence - this includes sequencing and comparing sections of DNA/RNA and proteins, molecular clock, phylogenetic relationships, among others

We can see evidences of microevolution within our own lifetime, such is in bacterial development of antibiotic resistance.  The ability to selectively breed plants and animals - like corn that has bigger ears on separate structures from the tassel, or dogs that have certain physiques and coat varieties - demonstrates how selection (in this case not natural but human-based) can change the genetics of a population over time.

Readings and Other Resources

Evolution 3 - Evidence and

Ch. 22 Evidence and Ch. 23 When

LOE rest of Ch 4

CK12 BC use the CK12 LSC sections

CK12 LSC 4.4-4.6

What is the Evidence for Evolution - both, Stated Clearly video overviews the lines of evidence for evolution Evolution: It's a Thing - scholar, Crash Course goes over the observable evidences used to support the theory of evolution The History of Earth - scholar, Bozeman Science on how we know how old things are, relatively and absolutely.  This video is actually designed for teachers, but it gives you an overview of important observations and evidences we have

So, a few things to note

• Do the readings and videos for this week
• If you haven't turned in your Astrobiology Project please do so this week
• Battle of the Beaks lab write-up due on the 28th
• Monster book colloquium and movie night is April 30th
• Present your vocabulary lists on April 28th for prize selection