Biology: Exploring Life

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Chapter 1
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• Biology Exploring Life

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What is Biology

• Biology can be defined as the study of Life
• Bio means Life and ology means Study Of
• It is a branch of science and a way of studying
  nature.

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What is a biologist

• A Biologist is a person who strives to
  understand, explain and describe the natural
  world of living things.
• Biologists try to answer questions about
• The number of organisms
• The kinds of organisms
• The rate of reproduction
• The relationships among all organisms
• Biologists focus on questions that deal with how
  life works not why should there be life.

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Why Study Biology

• Biology is relevant
• Great advances have been made in controlling and
  treating diseases caused by viruses, bacteria,
  parasites and organ failure
• Agricultural Biologists use bioengineering to
  develop new genetically enhanced pest resistant
  crops
• In making decisions about where to locate new
  living spaces for an ever increasing human
  population
• In bridging the gap between biology and
  technology related careers in the biotech fields
  of laboratory science and applied ecology.

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THE SCOPE OF BIOLOGY
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• Lifes levels of organization define the scope of
  biology
• Lifes structural hierarchy
• Defines the scope of biology, the scientific
  study of life

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• An ecosystem consists of all the organisms living
  in a par ticular area
• As well as the nonliving environmental components
• All the living organisms in an ecosystem
• Make up a community

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• A population
• Consists of a localized group of individuals of a
  species
• An individual living entity
• Is an organism

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• The hierarchy continues downward with
• Organ systems
• Organs
• Tissues
• Cells
• Organelles
• Molecules

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• Living organisms and their environments form
  interconnecting webs
• Ecosystems are characterized by the cycling of
  chemical nutrients from the atmosphere and soil
• To producers to consumers to decomposers and back
  to the environment

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• Energy flows one-way through an ecosystem
• From the sun to producers to consumers and exits
  as heat

Figure 1.2
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• Cells are the structural and functional units of
  life
• A cell
• Is the basic unit of life

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• New proper ties emerge
• From the complex organization of a system, such
  as a cell

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• Eukaryotic cells
• Contain membrane-enclosed organelles, including a
  DNA-containing nucleus
• Prokaryotic cells
• Lack such organelles

Figure 1.3
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EVOLUTION, UNITY, AND DIVERSITY
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• The unity of life All forms of life have common
  features
• DNA is the genetic information
• For constructing the molecules that make up cells
  and organisms

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• Each species genetic instructions
• Are coded in the sequences of the four building
  blocks making up DNAs two helically coiled chains

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• All organisms share a common set of features
• Ordered structures
• Regulation of internal conditions

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• Growth and development
• Energy use
• Response to environmental stimuli
• The ability to reproduce and evolve

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• The diversity of life can be arranged into three
  domains
• Organisms are grouped (classified)
• Into the prokaryotic domains Bacteria and Archaea
  and the eukaryotic domain Eukarya

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• Domains Bacteria and Archaea

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• Domain Eukarya includes
• Protists (protozoans and algae, falling into
  multiple kingdoms)
• The kingdoms Fungi, Plantae, and Animalia

Kingdom Fungi
275?
Kingdom Animalia
Protists (multiple kingdoms)
Kingdom Plantae
Figure 1.5C
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• Evolution explains the unity and diversity of
  life
• Charles Dar win
• Synthesized the theory of evolution by natural
  selection

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• Natural selection is an editing mechanism
• That occurs when populations or organisms, having
  inherited variations, are exposed to
  environmental factors that favor the reproductive
  success of some individuals over others

Figure 1.6B
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• All organisms have adaptations
• That have evolved by means of natural selection

Killer whale
Pangolin
Figure 1.6C
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THE PROCESS OF SCIENCE
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• Scientists use two main approaches to learn about
  nature
• Science
• Is a way of knowing
• Seeks natural causes for natural phenomena

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• Discovery Science
• In discovery science
• Scientists describe some aspect of the world and
  use inductive reasoning to draw general
  conclusion.

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• With hypothesis-based science, we pose and test
  hypotheses
• Hypothesis-based science involves
• Obser vations, questions, hypotheses as tentative
  answers to questions
• Deductions leading to predictions, and then tests
  of predictions to see if a hypothesis is
  falsifiable (Deductions are based on previous
  research and reliable fact based information).

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• A Case Study from Ever yday Life
• Deductive reasoning is used in testing hypotheses
  as follows
• If a hypothesis is correct, and we test it, then
  we can expect a par ticular outcome

Figure 1.8A
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• A Case Study of Hypothesis-Based Science
• In experiments designed to test hypotheses
• The use of control groups and experimental groups
  helps to control variables

Bar Graph-comparison of individual groups at one
point in time
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• Biology is connected to many impor tant issues in
  our lives
• Environmental problems and solutions
• Genetic engineering
• Medicine

Figure 1.9
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• Many technological advances
• Stem from scientific research
• The development of medicines to treat illness
• The development of devices to see inside of the
  human body
• The science-technology-society relationship
• Is an impor tant aspect of a biology course
• Enables students and their families to make
  intelligent decisions about health care
• Development of goods and services to improve the
  living standard throughout the world