AP BIOLOGYWhat to Expect?

Curriculum is determined by the College Board Goal is to prepare you for taking and passing

the AP Exam on May 11, 2015.

What is AP Biology?

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

Content Focus

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 Labs

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)

The Exam

63 multiple choice questions 6 grid in questions that will require

calculations (four function calculators with square root are allowed)

Multiple Choice

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)

Free Response

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.

Course Requirements

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

Inquiry 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

Discovery 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

Hypothesis-Based Science

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)

Deductive Reasoning

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.

The Scientific Method

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

Designing Controlled Experiments

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

Limitations of Science and Scientific Theories

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.

Science, Technology, and Society

The current AP course emphasizes four Big Ideas of Biology.

Big Idea #1: Evolution

The Big Ideas

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.

Evolution:

“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 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”

Charles Darwin

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.

Darwin’s Observations

In other words, the natural environment “selects” for beneficial traits

Populationwith variedinherited traits

Elimination of individualswith certain traits

Reproduction of survivors

Increasingfrequency of traits thatenhancesurvival andreproductivesuccess

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?

How do we define 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

What is Life?

order

adaptation

response

reproduction

growth/development

energy processing

regulation

To study life, it is useful to divide it into different levels of biological organization in which new properties emerge at each level.

Biological Hierarchy

biosphere

ecosystems

communities

populations

organisms

systems/organs

tissues

cells

organelles

molecules

atoms

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.

Emergent Properties vs. Reductionism

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

Systems Biology

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

Cellular Processes:

“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

Structure and Function

(a) Wings: have aerodynamically efficien shape

(c) Neurons: specifically designed to transmit and carry signals necessary to coordinate flight

(b) Bones: wing bones are strong but lightweight

Infoldings ofmembrane

Mitochondrion

(d) Mitochondria: energy for flight comes from the chemical reactions that are dependent upon the structure of the mitochondria

0.5 µm100 µm

Fig. 1-6

The relationship between structure and function can be seen at alllevels of biological hierarchy.

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

What are Cells?

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.

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.

Cell Communication

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.)

Negative vs. Positive Feedback

Fig. 1-13

Negativefeedback

Excess Dblocks a step

D

D D

A

B

C

Enzyme 1

Enzyme 2

Enzyme 3

D

(a) Negative feedback

W

Enzyme 4

XPositivefeedback

Enzyme 5

Y

+

Enzyme 6

Excess Zstimulates astep

Z

Z

Z

Z

(b) Positive feedback

As product D accumulates, it inhibits enzyme 1, thusslowing down production of more D.

As product Z accumulates,it stimulates enzyme 5, thusspeeding up the production of more Z

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.

Cell Communication through Generations

Living systems store, retrieve, transmit, and respond to information essential to life processes.

Genetics and Transfer of Information:

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

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.

DNA Structure and Function

NucleicontainingDNA

Sperm cell

Egg cell

Fertilized eggwith DNA fromboth parents

Embryo’s cells withcopies of inherited DNA

Offspring with traitsinherited fromboth parents

Fig. 1-9

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.

The Double Helix

Fig. 1-10

Nucleus DNA

Cell

Nucleotide

(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.

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

The role of the Environment

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

Ecology:

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.

Ecosystem Dynamics

Fig. 1-5

Sunlight

Ecosystem

Heat

Heat

Cyclingof

chemicalnutrients

Producers(plants and other photosynthetic

organisms)

Chemical energy

Consumers(such as animals)

Energy flows through an ecosystem, usually entering as sunlight and exiting as heatwhile chemicalnutrients recycle within an ecosystem.

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