© 2009 FIDM/The Fashion Institute of Design & Merchandising

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Chapter 1 – Biology: Exploring Life

THE SCOPE OF BIOLOGY 1. Life’s structural hierarchy, the levels of organization, defines the scope of biology, the

scientific study of life. From largest to smallest: a. biosphere = all Earth’s ecosystems b. ecosystem = all organisms living in an area, including nonliving environmental

components (such as the Florida coast) c. community = all the living organisms in an ecosystem (all organisms on the coast:

pelicans, crabs, seaweed) d. population = a localized group of individuals of a species (group of pelicans) e. organism (one species) = an individual living entity (a pelican) f. organ system = group of organs that work together to perform a specific function (such

as the nervous system) g. organ = part of an organ system, made of different tissues (such as the brain, spinal

cord) h. tissue = group of similar cells (nervous tissue) i. cells = basic unit of living matter (neuron, or nerve cell) j. organelles = small membrane enclosed structures within the cell (nucleus) k. molecules = cluster of atoms held together by chemical bonds (DNA)

2. Ecosystems - characteristics a. Cycling of chemical nutrients – chemicals necessary for life (carbon dioxide, oxygen,

water, minerals) cycle between the atmosphere and the soil to producers to consumers to decomposers and back into the air and soil

b. One-way energy flow – sunlight energy flows into the ecosystem and is trapped by photosynthesizers (such as green plants) and converted to chemical energy, which powers organisms, and continues through energy conversions until it is eventually converted to heat energy and lost from the system

3. Cells = the basic unit of life a. lowest level of structure that can perform all the activities required for life b. emergent properties = with each step upward in the hierarchy of biological order, new

properties emerge as a result of the arrangement and interactions of the new parts (just as bicycle parts function differently when assembled into a bicycle)

c. two types of cells: • prokaryotic cells – lack membrane-bound organelles • eukaryotic cells – contain membrane-enclosed organelles, including a nucleus

with DNA

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EVOLUTION, UNITY, AND DIVERSITY 1. All living organisms share common features:

a. DNA – contain the molecule that provides the genetic instructions for making cells and organisms; each species has its own set of instructions

b. Order – have complex organization c. Regulation – can maintain internal equilibrium with a changing external environment d. Growth and development – inherit information carried by genes that control growth

and dev e. Energy utilization – take in energy and transform it to perform life’s activities f. Response to the environment – respond to external stimuli g. Reproduction – reproduce own kind h. Evolution – change over time by adapting to environment

2. Diversity of Life a. About 1.8million species have been identified so far b. Taxonomy – branch of biology that names and classifies species c. Three overarching groups or domains: (once 5 kingdoms which are now under 3

domains) • Bacteria and Archaea include all the prokaryotes; once one kingdom now divided

into 2 domains; most unicellular and microscopic • Eukarya includes all the eukaryotes; the other 4 kingdoms are in this domain

(Protista, Fungi, Plantae and Animalia) 3. Evolution explains both the unity and diversity of life---biology’s core theme because it

explains all we know about life a. Charles Darwin – synthesized the theory of evolution b. “descent with modification” - species living today descended from an ancestral

species c. Natural selection – explains how the changes occurred: when populations of

organisms, having inherited variations, are exposed to environmental factors, those with variations that are best adapted to the environment have more reproductive success than others; in other words,

• individual variations + overproduction of offspring = natural selection: unequal reproductive success

THE PROCESS OF SCIENCE 1. Science = Latin for “to know” 2. Scientific inquiry- 2 types

a. Discovery science – scientists describe what they observe and use inductive reasoning to draw general conclusions

b. Hypothesis-based science – observations from discovery science lead to seeking explanations; thus scientists use deductive reasoning to propose and test hypotheses

3. Hypothesis-based science involves observations, questions, hypotheses as tentative answers, deductions leading to predictions, tests to see if hypothesis is falsifiable