AP Biology Chapter 1 A View of Life

Biology - the study of life Constantly changing Increasing quality of life Drastically changing health care New discoveries daily Technology

Themes of Biology Evolution of life Diverse life forms are related Transmission of information DNA, Chemical signaling Flow of energy through living systems Energy constantly required to maintain complex processes

Characteristics of Organisms Cells – organisms are made of one or more cells Cell Theory: All living organisms are composed of cells New cells arise from existing cells Cells are basic unit of structure and function of living things Schleiden, Schwann, and Virchow **Cell Theory Video

Characteristics of Organisms Organisms grow and develop Biological growth - increase in the size of cells or the number of cells Growth may be uniform or greater in some parts than others Development - all the changes that take place during an organism's life

Metabolism - the sum of all the chemical activities of the organism Processes occur continuously in every living organism Must be carefully regulated to maintain homeostasis Homeostatic mechanisms are control systems that maintain constant levels of cellular products in the organism Example - regulation of glucose in the blood of complex animals

Heterotrophs – organism that obtains food by consuming other living organisms Autotrophs – organism that makes its own food Photosynthesis Chemosynthesis **Metabolism Video Clip

Characteristics of Organisms Movement - basic property of cells Many varieties of movement Extensions such as cilia (hairlike) and flagella (longer structures) Animals move obviously (swim, crawl, run, fly) - have complex tissues for movement = muscles! Even plants move toward the sun or trap insects

Characteristics of Organisms Organisms respond to stimuli Stimuli that evoke a response in organisms: Changes in light intensity, direction, or color Changes in temperature, pressure, or sound Changes in the chemical composition of the surrounding soil, air, or water Plants respond to stimuli too!

Characteristics of Organisms Reproduction Asexual - exact copy of parent, ex. bacteria Sexual - egg and sperm cells combine to form a fertilized egg, provides genetic variation Can be internal or external fertilization

Characteristics of Organisms Adaptations Adaptations are traits that enhance an organism's ability to survive Every organism is a complex collection of coordinated adaptations produced through evolutionary processes

Transmission of Information Instructions are needed to carry out life processes DNA - genetic material Watson and Crick, 1953 Makes up genes - the hereditary units Used to specify instructions for making every living organism

Transmission of Information DNA contains the information to make all the proteins needed by an organism Proteins determine the structure and function of cells and tissues Cells also use proteins to communicate with one another Cell signaling *Learning to manipulate cell signaling may lead to new discoveries in the medicine.

Chemical Transmission of Information Hormones - molecules that function as chemical messengers that transmit information from one part of an organism to another Can signal cells to produce a protein or other substance

Electrical Transmission of Information Nervous Systems Electrical Impulses Neurotransmitters - chemical compounds Ex. Transmit message from eyes and ears to the brain

Biological Organization Hierarchical At every level, structure and function are coordinated Solomon p.9 Chemical – atoms Molecule – atoms combine Cell – atoms and molecules form cells (basic structure of living things) Tissue – cells working together Organ – tissues organized Organ System – group of tissues and organs Organism – organ systems working together Smallest Largest

Ecological Organization Population – all the members of one species that live in the same geographic area at the same time Community – the populations of organisms that inhabit a particular area and interact with one another Can be hundreds of different organisms

Ecological Organization Ecosystem – a community together with its nonliving environment Can vary greatly in size Biosphere – all of Earth’s ecosystems together Ecology – the study of how organisms relate to one another and to their environment

Evolutionary Relationships Systematics – studies evolutionary relationships Taxonomy – the science of naming and classifying organisms Binomial nomenclature – each species is assigned a two-part name 1 st part of name = genus 2 nd part of name = specific epithet

Taxonomic Classification Remember: King Phillip Came Over For Good Spaghetti Kingdom, Phylum, Class, Order, Family, Genus, Specific epithet See page 11 (table 1-1) 3 domains: Archaea, Eubacteria, and Eukarya 6 kingdoms: Plant, Animal, Fungi, Protista Archaebacteria, Eubacteria

Evolution is the primary unifying concept of biology Theory of evolution explains how populations change over time Natural Selection – mechanism by which evolution proceeds Organisms that possess favorable adaptations to their environment survive and pass on genes to next generation

Biology is Studied using the Scientific Method Involves a series of ordered steps and is the framework used by scientists Scientists make careful observations, ask critical questions, and develop hypotheses Then, scientists make predictions, test their predictions, interpret results, and draw conclusions See page 17 (figure 1-16)

Scientific Method A properly designed experiment includes: a control group and experimental group Only differ with respect to the variable being studied Must be free of bias!

Scientific Method When a number of related hypotheses have been supported many times, scientists develop a theory A theory is a well researched and supported scientific statement. A well established and tested theory may be referred to as a scientific principle