Paul Andersen describes how free energy is used by organisms to grow, maintain order, and reproduce. A brief discussion of the first and second law of thermodynamics is also included. Disruptions in the amount of free energy can cause...

Paul Andersen explains how feedback loops allow living organisms to maintain homeostasis. He uses thermoregulation in mammals to explain how a negative feedback loop functions. He uses fruit ripening to explain how a positive feedback...

Mr. Andersen gives a brief description of osmosis. He explains how water moves from a hypotonic to a hypertonic solution across a semipermeable membrane. The video ends with a time-lapse demon in class.

In this video Paul Andersen explains how you can combine the power of a Punnett square for an entire gene pool. Hardy-Weinberg equilibrium will remains constant under several constrains and the probability square makes the information...

Explore the cell cycle with the Amoeba Sisters and an important example of when it is not controlled: cancer. Table of Contents: 00:00 Intro 1:00 Cell Growth and Cell Reproduction 1:42 Cancer (explaining uncontrolled cell growth) 3:27...

Paul Andersen describes four important homeostatic loops in biology. He begins with a brief description of the elements of a homeostatic loop. He then describes how the hypothalamus helps us maintain a stable internal body temperature....

In this video Paul Andersen explains the elements in the Hardy-Weinberg equation; including the allele frequency and phenotype frequency. He begins with a brief explanation of phenotypes and genotypes. A sample problem is worked out...

In this video Paul Andersen explains how to run the student's t-test on a set of data. He starts by explaining conceptually how a t-value can be used to determine the statistical difference between two samples. He then shows you how to...

In this video Paul Andersen answers this question about chromosomes. He explains how the base pairs of DNA form genes which are organized into the chromosomes of the overall genome.

Paul Andersen explains how genotypes can be expressed or not based on changes in the environment. He starts with a brief description of the Himalayan rabbit and how melanin production can be disrupted by high temperature. He explains...

Paul Andersen shows you how to solve simple Hardy-Weinberg problems. He starts with a brief description of a gene pool and shows you how the formula is derived. He then shows you how to solve a couple of sample problems.

Paul Andersen describes mechanisms that increase the genetic variation within a population. He begins by discussing how horizontal transfer can move genetic material between bacteria. Transformation, transduction, and conjugation in...

Paul Andersen explains the two major portions of the molecular biology lab in AP Biology. He starts by discussing the process of transformation. He explains how you can use the pGLO plasmid to produce glowing E. coli bacteria. He then...

Mr. Andersen talks you through the diffusion demo. After you finish watching this video you should be able to rank the following from smallest to largest: starch, glucose, water, IKI and the pores in the dialysis tubing.

Paul Andersen explains how pigments can be separated using chromatography. He shows how you can calculate the Rf value for each pigment. He then explains how you can measure the rate of photosynthesis using leaf chads and water...

Paul Andersen explains the concept of coevolution. He begins with an analogy comparing the relationship of humans to technology with those of coevolving species. He then discriminates between coevolution and convergent evolution. He...

Paul Andersen explains how organisms are able to regulate their internal body temperature (or not). He starts with a brief description conduction, convection, radiation and metabolism. He contrasts ectotherms and endotherms. He also...

Mr. Andersen shows you how to sink leaf chads in preparation for the AP Biology photosynthesis lab. An empty syringe is used to remove gas from the leaves before the lab. As the chloroplasts absorb light they produce oxygen bubbles...

Paul Andersen describes the major mutations found in the living world. He starts with an analogy comparing the information in DNA with the information in a recipe. Changes in the DNA can result in changes to the protein, like changes...

Paul Andersen discusses the defining characteristics of the members of Domain Eukarya. He starts with a brief description of the phylogeny of life on earth. He then discusses the major characteristics of eukaryotic cells. He explains...

In this video Paul Andersen explains how the frequency of recombination between linked genes can be used to determine the relative location of genes on a chromosome. Thomas Hunt Morgan and Alfred Strutevant used the fruit fly to develop...

Paul Andersen shows you how to find stomata in a dicot and monocot leaf using finger nail polish and transparent tape. A microscope is required to actually see the stomata.

Paul Andersen explains how your body protects itself from invading viruses and bacteria. He starts by describing the nonspecific immune responses of skin and inflammation. He then explains how we use antibodies to disrupt the function...

Paul Andersen explains the importance of biodiversity. He starts by describing how biodiversity can be species, genetic or ecosystem diversity. He explains the importance of keystone species in an environment and gives two examples;...