The Molecular Clock and Estimating Species Divergence | Learn Science at Scitable A recent study by Weir and Schluter (2008) demonstrates the use of different calibration techniques. To estimate the evolutionary rate of the mitochondrial gene encoding cytochrome b in birds, Weir and Schluter chose 90 different calibrations derived from dated fossils and from the formation ages of land bridges, oceanic islands, and mountain ranges. They then used a statistical method to check each of these calibrations and discarded 16 that were found to be inconsistent. Weir and Schluter also noted that the rate of molecular evolution varies significantly among different bird species. The findings of Weir and Schluter demonstrate that it can be unwise to calculate an evolutionary rate using one group of organisms and then extrapolate that rate to another group, even when one is comparing relatively similar species.
Semicolons Today's topic is semicolons. I get questions about semicolons a lot, so it's time to clear up some confusion. Use Semicolons to Separate Things and Add Variety Semicolons separate things. Here's an example: "It was below zero; Squiggly wondered if he would freeze to death." One reason you might choose to use a semicolon instead of a period is if you wanted to add variety to your sentence structure, for example, if you thought you had too many short, choppy sentences in a row. What's the Difference Between a Semicolon and a Colon? People often ask me what the difference is between a semicolon and a colon, and there are a couple of differences. Semicolons separate things. The second difference between a colon and a semicolon is that when you are joining things, you use a semicolon to join things of equal weight, whereas you can use a colon to join things of equal or unequal weight. One way that I remember this is to think of the different elements as railroad cars. References 1. Diversions
Teacher Toolbox Home » Teacher Toolbox This page contains documents and links I used in teacher workshops I conducted as part of the NSF GK-12 Program at the Environmental Science Institute at the University of Texas at Austin, or referred to in training sessions I currently conduct for the National Math and Science Initiative. These files will be updated periodically as new workshops are developed. Although I am no longer formally associated with the Environmental Science Institute, I remain a strong supporter of their work. I do not post materials from the National Math & Science Initiative on this site. Editable 2013 AP Biology Syllabus in Pages (ZIP 961 KB)This is the original format. Editable 2013 AP Biology Syllabus in Word (DOC 0.99 MB) Editable 2013 APES Syllabus in Pages (ZIP 2.72 MB) Editable 2013 APES Syllabus in Word (DOC 6.30 MB) Field Card for Macroinvertebrates (PDF 12 KB)This is a single two-sided card to use in the identification of aquatic invertebrates in the field. What Is a Nanometer?
Gardening - Gardening Guides - Techniques - Taking pelargonium cuttings Explore Biology | Teachers' Center | Biology Teaching Resources Welcome to the Teachers' Center at Explore Biology. Here you will find resources to help you teach biology at the high school level. Some of my Regents lectures are supported by Powerpoint presentations. If you are not familiar, Regents is a 10th grade very simplified introduction to Biology, that is limited by a state-wide exam. These PPTs are not appropriate for AP Biology courses! I have just started to upload these, so please check back if you need. Check out what we're doing online to expand beyond the classroom to the virtual world -- to catch students wherever they hang out and entice them to think! These daily worksheets are aligned with the Raven (7th ed.) textbook. NOTE: I have moved all the molecule building activities over to AP Biology Lab & Activities Section Post-AP Activities -- what to do with the students after the AP exam Children's Book -- I have students produce a children's book based on one biology concept or subject. Summer Assignments Summer Assignment 2010
Plant Growth Factors: Plant Hormones Thought Questions Explain the science behind the following gardening questions: 1. A couple of times a year, I sheer my shrubs into nice rounded shapes. Now my shrubs have large woody stems with a lot of dead branches. 2. Plant Hormones and Plant Growth Regulators Another factor in plant growth is the influence of plant hormones. Plant growth regulators are chemicals applied by a horticulturist to regulate plant growth. Plant Hormones Different hormones affect different plant processes. Auxins produced in the terminal buds suppress the growth of side buds and stimulate root growth. Figure 1. Gibberellins affect: The rate of cell division Flowering Increase in size of leaves and fruits Seed and bud dormancy Induction of growth at lower temperatures (used to green up lawns 2 to 3 weeks earlier) Cytokinins promote cell division, and influence cell differentiation and aging of leaves. Hormone Influence on Pruning Understanding hormones is key to proper pruning. Figure 2. Figure 3. Tropism
The Biology Project PWHS: Thermodynamics: Convection The Movement of Heat by Convection Heat can move from one place to another by the process of convection in any fluid (a word that includes liquids, gases and plasmas). This happens when one part of the fluid has a higher temperature than its surroundings, and thus expands. When it expands it becomes less dense, and therefore rises, while the colder fluid rushes in below to fill the space. The process of convection: is what makes all the water in a pot boil rather than just the water at the bottom is responsible for keeping lakes and oceans from freezing from the bottom up (see Water: the Great Anomaly handout) lets birds of prey and gliders fly without flapping their wings or using an engine is an essential part of many geologic processes is largely responsible for solar flares and the granulated appearance of the sun’s surface is responsible for the ‘great ocean conveyer belt’ which keeps the oceans circulating, which keeps much of Europe from freezing! Home
Frequently Asked Questions High School Bioethics Curriculum Project*(HSBCP) FAQ: Teaching Bioethics in the High School Classroom Q. What is the format of the HSBCP Curriculum? Q. A. Sciences, Social sciences, And the humanities. The HSBCP's Curriculum may be and has been used in: Public AND private schools Secular AND religious schools Single-sex AND coed schools Racially/ethnically homogenous AND racially/ethnically heterogeneous schools Large AND small class sizes Teacher-lead AND team taught classesBack to the Top Q. A. Depending on your course requirements and classroom schedule, you may use: Just one case Single cases from one or several units scattered throughout a course An entire unit (5 to 8 Cases) The entire curriculum as the core for an elective or advanced courseBack to the Top Q. A. Q. A. Q. A. Q. A. Q. A. Q. A. This FAQ page is largely based on materials developed by Linda Anderson, The Potomac School, McLean, VA.
Viruses: Nuts and Bolts of a Bacteriophage A virus is a nonliving particle that depends on a host to reproduce. There are different types of viruses, but all consist of a capsid, an outer protein coat, and some genetic material. Some viruses contain DNA and others RNA. Materials Small bolt Two nuts One washer Six small pieces of pipe cleaners Activity Use the materials provided to build a bacteriophage model, referring to the illustration in Figure 9.2 as needed for guidance. Follow-Up Questions What did you use for the capsid of the virus? Answers Answers will vary. Extension Viruses are generally classified according to their DNA or RNA content. From The Science Teacher's Activity-A-Day.
Teaching Genetic Linkage and Recombination through Mapping with Molecular Markers | CourseSource Genetic linkage and recombination are core concepts in an undergraduate genetics curriculum(1), but many educators find the traditional method of teaching this topic is problematic. Despite the common challenges encountered when teaching genetic linkage, we were surprisingly unable to find published information providing teaching strategies or tips to improve student understanding of genetic linkage and recombination. Typically, students analyze crosses involving somewhat random phenotypes, such as 'Waltzing' or 'bent-tail' mice(2), and even after instruction and practice, they are rarely able to articulate the utility of understanding or using genetic linkage. We wanted to provide students with a compelling practical and experimental context that targeted these common difficulties in learning about linkage and recombination. Microsatellites are tandem repeats of two to six base pairs. Intended Audience Learning time Pre-requisite student knowledge S1a.
BSI :: How it Works? The immune system has two parts – 'innate' and 'adaptive' Innate immunity The 'innate' (meaning: "present from birth") part of the immune system is so-called because it has a number of set strategies for recognising and dealing with certain kinds of infection, without needing to be "trained" to identify them. This approach is very effective for many infections, but certain germs have developed ways of avoiding detection. During infections, signs such as the swelling and inflammation of the skin are often indications of immune activity, as they help the immune system by allowing blood carrying immune elements to flow more easily to the site of infection. Adaptive immunity The other part of the immune response is called the 'adaptive' immune system. Doctors can trick the body into producing a memory to a particular infection by using vaccines (harmless versions of germs) to create immune 'memory'. On patrol for signs of trouble… Immunity in the gut: an important balancing act Key Facts:
Chemistry Virtual Textbook Acid-base chemistry can be extremely confusing, particularly when dealing with weak acids and bases. This set of lessons presents an updated view of the Brønsted-Lowry theory that makes it easy to understand answers to common questions: What's the fundamental difference between a strong acid and a weak acid? Can acid A neutralize base B? This complete rewrite of the previous 1996 pdf document is now organized into seven lessons covering all aspects of the subject. Much emphasis is placed on the practical aspects of calculations, including how to deal with quadratic equations and how to judge when approximations are appropriate.
Introduction to Solutions Introduction to Solutions Return to Solutions Menu A solution is a particular type of mixture. Mixtures in chemistry are combinations of different substances where each substance retains its chemical properties. Generally, mixtures can be separated by non-chemical means such as filtration, heating, or centrifugation. A solution is a homogeneous mixture, but that's not the full definition. A solution is a homogeneous mixture where all particles exist as individual molecules or ions. By the way, there are homogeneous mixtures where the particle size is much larger than individual molecules. A solution has two components: the solute and the solvent. The solvent is the substance in greater amount. It is usually a liquid, although it does not have to be. The solute is the substance in lesser amount. It is usually a solid, although it does not have to be. Ya know, I can just see that gleam in your eye. You finish the story. The word concentration refers to how much solute is dissolved.