AP BIOLOGY What to Expect?

What is AP Biology? Curriculum is determined by the College Board Goal is to prepare you for taking and passing the AP Exam on May 11, 2015.

Content Focus The course content is structured around Four Big Ideas: Evolution Cellular Processes Genetic and Information Transfer Ecology

The Labs The AP labs are inquiry based Students will: Generate questions for investigation Choose which variables to investigate Design and conduct experiments Design their own experimental procedures Collect, analyze, interpret and display data Determine how to present their conclusions

The Exam Two sections: multiple choice and free response. 3 hours long: 90 minute multiple choice (50% of grade) 90 minute free-response section that begins with a mandatory 10 minute reading period (50% of grade)

Multiple Choice 63 multiple choice questions 6 grid in questions that will require calculations (four function calculators with square root are allowed)

Free Response Two long free response questions (10 points each: one of which will definitely be on inquiry lab design) Six short free response questions (range from 3 to 6 points each)

Course Requirements Notes: You will keep your own notebook. Notes will not count for a grade. They are for your reference. Study from them for the unit tests and for the exam prep. Lab Reports: Several typed lab reports will be required for many of the labs. Tests: Summative tests will be given at the completion of each unit. Projects: TBA Homework: You will be expected to complete reading assignments and homework on time.

Inquiry Science The AP curriculum places an emphasis now placed on inquiry science. The word Science is derived from Latin and means, “to know” Inquiry is the search for information and explanation. There are two main types of scientific inquiry: discovery science and hypothesis-based science

Discovery Science Discovery science describes natural structures and processes This approach is based on observation and the analysis of data (both qualitative and quantitative data) Inductive reasoning can be used to draw conclusions based on the observations made. Ex: The sun always rises in the east Ex: All organisms are made of cells

Hypothesis-Based Science Observations can lead us to ask questions and propose hypothetical explanations called hypotheses A hypothesis is a tentative answer to a well- framed question A scientific hypothesis leads to predictions that can be tested by observation or experimentation A hypothesis must be both testable and falsifiable

Deductive Reasoning Deductive reasoning is used more in Hypothesis-based science. It uses general premises to make specific predictions (start with the general knowledge and extrapolate the specific results) Ex: If organisms are made of cells (premise 1), and humans are organisms (premise 2), then humans are composed of cells (deductive prediction)

The Scientific Method The scientific method is an idealized process of inquiry Hypothesis-based science is based on the “textbook” scientific method but rarely follows all the ordered steps. Discovery science has made important contributions with very little dependence on the so-called scientific method.

Designing Controlled Experiments A controlled experiment compares an experimental group with a control group Ideally, only the variable of interest differs between the control and experimental groups A controlled experiment means that control groups are used to cancel the effects of unwanted variables A controlled experiment does not mean that all unwanted variable are kept constant (this is actually impossible in field studies) Read Snake mimicry case study in textbook pgs. 20-22

Limitations of Science and Scientific Theories In science, observations and experimental results must be repeatable Science cannot support or falsify supernatural explanations, which are outside the bounds of science. In the context of science, a theory, is: Broader in scope than a hypothesis General, and can lead to new testable hypotheses Supported by a large body of evidence in comparison to a hypothesis

Science, Technology, and Society The goal of science is to understand natural phenomena The goal of technology is to apply scientific knowledge for some specific purpose The two are interdependent Many ethical issues can arise from new technology, but have as much to do with politics, economics, and cultural values as with science and technology. This course will explore some of these types of ethical issues.

The Big Ideas The current AP course emphasizes four Big Ideas of Biology. Big Idea #1: Evolution

Evolution: The process of evolution drives the diversity and unity of life. It is the process of change that has transformed life on Earth throughout history. “Nothing in biology makes sense except in the light of evolution”—Theodosius Dobzhansky (helped develop modern evolutionary synthesis…wrote “Genetics and the Origin of Species” 1937)

Charles Darwin Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859. Darwin made two main points: Species showed evidence of “descent with modification” from common ancestors (this phrase shows unity in the kinship of species and diversity in the modifications that evolved) Natural selection is the mechanism behind “descent with modification”

Darwin’s Observations Darwin observed that: Variation exists among individuals in a population Traits are passed from parents to offspring Overproduction exists in most species Competition is inevitable Species generally suit their environment Thus, individuals that are best suited to their environment are more likely to survive and reproduce. Overtime, more individuals in a population will have the advantageous traits.

In other words, the natural environment “selects” for beneficial traits Population with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors Increasing frequency of traits that enhance survival and reproductive success

How do we define life? So if Evolution is the core theme of biology, and helps to explain both the unity and diversity of life, then how do we define life? What is a living thing?

What is Life? Life defies a simple, one-sentence definition Life is recognized by what living things do. Properties of life include: Order Evolutionary adaptation Response to environment Reproduction Growth and Development Energy processing Regulation response order adaptation regulation energy processing reproduction growth/ development

Biological Hierarchy To study life, it is useful to divide it into different levels of biological organization in which new properties emerge at each level. biosphere cells systems/ organs ecosystems organelles communities atoms tissues populations molecules organisms

Emergent Properties vs. Reductionism Emergent properties result from the arrangement and interaction of parts within a system New properties emerge as levels increase Ex: nerve cells “fire” but a brain “thinks” Reductionism is the reduction of complex systems to simpler components Ex: studying the molecular structure of DNA allowed us to discover how it could serve as the chemical basis of inheritance.

Systems Biology An understanding of biology balances reductionism with the study of emergent properties This often involves systems biology, which constructs models for the dynamic behavior of whole biological systems. Such models allow biologists to predict how a change in one or more variables will affect other components and the whole system. This leads us to Big Idea #2: Cellular Processes

Cellular Processes: Biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis.

Structure and Function “Form fits Function” is a guide to the anatomy of life. Structure and function of living organisms are closely related. Ex: a leaf is thin and flat, maximizing the capture of light by chloroplasts

The relationship between structure and function can be seen at all Fig. 1-6 The relationship between structure and function can be seen at all levels of biological hierarchy. (a) Wings: have aerodynamically efficien shape (b) Bones: wing bones are strong but lightweight Infoldings of membrane Mitochondrion Figure 1.6 Form fits function in a gull’s wing 100 µm 0.5 µm (c) Neurons: specifically designed to transmit and carry signals necessary to coordinate flight (d) Mitochondria: energy for flight comes from the chemical reactions that are dependent upon the structure of the mitochondria

What are Cells? The cell is an organism’s basic unit of structure and function Two basic types: Eukaryotic: contain an nucleus and membrane- bound organelles Prokaryotic: no nucleus or membrane-bound organelles

All cells are enclosed by a membrane that controls what gets in and what gets out All cells use DNA as their genetic information The ability of cells to divide is the basis of all reproduction, growth and repair of multicellular organisms.

Cell Communication Cells of multicellular organisms must also be able to communicate. Chemical feedback mechanisms regulate many biological systems These chemical pathways are catalyzed by enzymes and allow biological processes to self-regulate.

Negative vs. Positive Feedback Negative feedback means that as more of a product accumulates, the process that creates it slows and less of the product is produced. Ex: ATP production (When a cell makes more ATP than it can use, the ATP “feeds back” and inhibits an enzyme at the beginning of the pathway.) Positive feedback means that as more of a product accumulates, the process that creates it speeds up and more of the product is produced Ex: Blood clotting (Platelets aggregate at a damaged blood vessel. They release chemicals that attract more platelets to the site.)

As product D accumulates, it inhibits enzyme 1, thus Fig. 1-13 A Negative feedback  Enzyme 1 As product D accumulates, it inhibits enzyme 1, thus slowing down production of more D. B D Enzyme 2 Excess D blocks a step D D C Enzyme 3 D (a) Negative feedback W Enzyme 4 As product Z accumulates, it stimulates enzyme 5, thus speeding up the production of more Z Figure 1.13 Regulation by feedback mechanisms X Positive feedback + Enzyme 5 Excess Z stimulates a step Z Y Z Z Enzyme 6 Z (b) Positive feedback

Cell Communication through Generations Cells also must be able to transfer information from one generation to another. This leads us to Big Idea #3: Genetics and Transfer of Information.

Genetics and Transfer of Information: Living systems store, retrieve, transmit, and respond to information essential to life processes.

DNA The continuity of life is based on heritable information in the form of DNA Chromosomes contain most of a cell’s genetic material in the form of DNA (deoxyribonucleic acid) Genes are the units of inheritance that transmit information from parents to offspring.

DNA Structure and Function Each chromosome has one long DNA molecule with hundreds or thousands of genes DNA is inherited by offspring from their parents and controls the development and maintenance of organisms.

copies of inherited DNA Egg cell Offspring with traits inherited from Fig. 1-9 Sperm cell Nuclei containing DNA Fertilized egg with DNA from both parents Embryo’s cells with copies of inherited DNA Egg cell Offspring with traits inherited from both parents Figure 1.9 Inherited DNA directs development of an organism

The Double Helix The molecular structure of DNA accounts for its ability to store information Each DNA molecule is a double helix made of building blocks called nucleotides.

(b) Single strand of DNA Fig. 1-10 Nucleus DNA Nucleotide Cell Figure 1.10 DNA: The genetic material (a) DNA double helix (b) Single strand of DNA

A particular sequence of nucleotides is called a gene. Genes control protein production indirectly, and different proteins control different cell activities. Thus, DNA provides the blueprints, and proteins serve as the tools that actually build and maintain the cell and carry out its activities.

The role of the Environment Communication goes beyond the cellular level Organisms must also communicate with each other and interact with their environment. This leads us to Big Idea #4: Ecology

Ecology: Biological systems interact, and these systems and their interactions possess complex properties.

Ecosystem Dynamics Every organism interacts with its environment, including nonliving factors and other organisms. Both organisms and their environments are affected by these interactions. The dynamics of an ecosystem include two major processes: Cycling of nutrients, in which materials acquired by plants eventually return to the soil Flow of energy from sunlight to producers to consumers.

(plants and other photosynthetic Fig. 1-5 Sunlight Ecosystem Energy flows through an ecosystem, usually entering as sunlight and exiting as heat while chemical nutrients recycle within an ecosystem. Producers (plants and other photosynthetic organisms) Cycling of chemical nutrients Heat Chemical energy Figure 1.5 Nutrient cycling and energy flow in an ecosystem Consumers (such as animals) Heat

All organisms must perform work, which requires energy. Energy can be stored in different forms, for example, light, chemical, kinetic, or thermal The energy exchange between an organism and its environment often involves energy transformations