Chapter 1: What is Biology?

Natural selection

Charles Darwin: the mechanism behind "descent with modification" Species showed evidence of "descent with modification" from common ancestors •In other words, the environment "selects" for the propagation of beneficial traits - acts on individuals in a population

Charles Darwin and the Theory of Natural Selection

Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species

A survey of the three domains of life

Domain Bacteria: - Bacteria Domain Archaea: - Archaea Domain Eukarya - Protists - Plants - Animals - Fungi

Cells

Every living organism is composed of one or more cells

Sexual

Fusion of egg and sperm

Development

-All changes that occur during an organism's life (changes overtime)

Biological growth

-An increase in size of individual cells of an organism, in number of cells or in both

Prokaryotic cells

-Exclusive to Bacteria and Archaea -Structurally simple: do not have a nucleus or other membrane-bound organelles

§Adaptations

-Inherited characteristics that enhance the ability to survival in a particular environment -May be structural, physiological, biochemical, behavioral or a combination of all four

Organelles

-internal structures of cells that are specialized to perform specific functions

Levels of Organization in Nature

1 Atoms are fundamental units of matter. 2 Molecules consist of atoms. 3 Cells consist of molecules. 4 Organisms consist of cells. 5 Populations consist of organisms. 6 Communities consist of populations. 7 Ecosystems consist of communities interacting

Steps of The Scientific Method

1) Observe some aspect of nature. 2) Make a prediction based on the hypothesis 3) Analyze the results of the tests (data).

The Study of Life: Common Themes

1. Biological systems interact 2. Structure and function are inter-related 3. Information must be transferred 4. Life depends on a continuous input and transfer of energy 5. Populations change over time through the process of evolution

Characteristics of Life

All organisms: -Are composed of cells -Grow and develop -Regulate their metabolic processes -Respond to stimuli -Reproduce -Adapt to the environment and evolve

autotrophic

Plants and other photosynthetic organisms convert the energy of sunlight into the chemical energy of sugars

Data

Test results

What is Biology?

The scientific study of life

DNA

Transmits Information from One Generation to the Next

Asexual

Variation occurs only by mutations

Taxonomy

a subspecialty of systematics; the science of naming and classifying organisms

Gene pool

all the genes in a population (a reservoir of genetic variation)

The Linnaean system

binomial system of nomenclature because each species has a two-part name: - First part: genus - Second part: : the specific epithet; designates a particular species in that genus

DNA

contain genetic instructions and transmit genetic information

Multicellular

depend on coordinated functions of cells organized to form tissues, organs, and organ systems

Experimental group

group of individuals who receive a certain treatment

Unicellular

life-forms: consist of a single cell

The Scientific Method

making observations, forming logical hypotheses, and testing them

Stimuli

physical or chemical changes in the external or internal environment that cause movement

producers

produce chemical energy

Plasma membrane

protects the cell and regulates passage of materials between the cell and its environment

consumers

that feed on the producers

Evolution

the gradual modification of populations of living things over time, explains patterns of unity and diversity in living organisms

Independent variable

the treatment or condition under study

Eukaryotic cells

typically contain a variety of organelles enclosed by membranes, including a nucleus, mitochondria , ribosomes , Endoplasmic reticulum , etc.

Cytoplasm

watery fluid inside of cell

Reductionism

we learn about a structure by studying all its parts

Three Domains

•Bacteria, • Archaea, • Eukarya

Cladogram

•branching diagram showing proposed evolutionary relationships among organisms and fossil evidence

Homeostatic mechanisms

•carefully regulate metabolic processes to maintain an appropriate, balanced internal environment

Control group

•group not exposed to the variable being tested

Metabolism

•includes all chemical activities that take place in an organism •Chemical reactions essential to nutrition •Growth and repair •Conversion of energy

theory

•is a general set of principles, supported by evidence, that explains some aspect of nature.

•Dependent variable

•the event or condition that is measured