Biology: Exploring Life

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Chapter 1 Biology Exploring Life
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What is Biology?

• The study of life or living organisms.

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Ecosystem
Community
Population
Organism
Organ Systems
Organs
Tissue
Cell
Organelle
Molecule
Atom
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Levels of Organization(large scale)

• Ecosystem
• Both living organisms and non-living or physical
  components of environment in a particular area

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Levels of Organization(large scale)

• Community
• All interacting organisms in an area (living
  component only)

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Levels of Organization

• Population
• Individuals of one species living in same area

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Levels of Organization

• Individual
• One organism

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Levels of Organization (within an Individual)

• Organ Systems
• group of organs that work together in performing
  vital body functions
• excretory, nervous

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Levels of Organization (within an Individual)

• Organs
• structure consisting of several tissues adapted
  as a group to perform specific functions
• liver, intestine

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Levels of Organization (within an Individual)

• Tissues
• integrated group of cells with a common function,
  structure, or both

Bone tissue
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Levels of Organization (within an Individual)

• Cell
• Unit of living matter separated from environment
  by its membrane

red blood cell
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Levels of Organization (within an Individual)

• Molecule
• Cluster of atoms

DNA, lipid, carbohydrate
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Levels of Organization (within an Individual)

• Atom
• Smallest particle of ordinary matter

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Emergent properties

• New properties that emerge with each step in the
  hierarchy of life
• e.g., birth rate, death rate is studied at
  population level, not organismal level or
  molecular level

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Interconnected Webs

• producers
• photosynthetic organisms
• provide food for others
• consumers
• eat plants or other animals
• decomposers
• act as recyclers, breaking down dead matter to
  simple mineral nutrients

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Sunlight
Ecosystem
Producers (such as plants)
Cycling of chemical nutrients
Heat
Chemical energy
Consumers (such as animals)
Heat
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Cells structural functional units of life

• Cells-
• most basic unit of life
• can perform all functions necessary for life.

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Common Features of All Life

• Properties All Life Has in Common
• Order
• Regulation
• Growth and development
• Energy processing
• Response to Environment
• Reproduction
• Evolutionary adaptation

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Three Domains of Life

• taxonomy
• branch of biology that names classifies species

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Three Domains of Life

• Domain
• Highest level of taxonomic classification used by
  biologists
• Bacteria
• Archaea
• Eukarya

prokaryotes
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Bacteria
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Archaea
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• In Prokaryotes, the cells do not have a nucleus

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Eukarya

• Cells DO have nucleus
• Includes all organisms except prokaryotes

Plantae
Animalia
Fungi
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Unifying Theory Of Biology

• Theory
• Comprehensive idea that has great explanatory
  power
• Evolution
• Heritable changes that have produced Earths
  diversity of organisms
• proceeds through process of natural selection

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Charles Darwin

• Wrote On the Origin of Species by Means of
  Natural Selection

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Charles Darwin

• Two main concepts
• species living today descended from ancestral
  species
• natural selection occurs as heritable variations
  are exposed to environmental factors that favor
  reproductive success of some individuals over
  others

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Natural Selection

• Inherited traits favor reproductive success of
  some individuals over others in a changing
  environment

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Natural Selection

• Important Components
• Variation or variability in inherited traits in a
  population
• Environmental Factors
• Reproductive Success of Some Individuals

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Natural Selection

• The process of natural selection leads to
• ADAPTATIONS.
• evolutionary adaptation-
• inherited characteristic that enhances an
  organisms ability to survive and reproduce in a
  particular environment.

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Name Those Adaptations

• Polar Bear

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Name Those Adaptations

• Bats

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Name Those Adaptations

• Dolphin

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Name Those Adaptations

• platypus

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Name Those Adaptations

• Three-toed sloth

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Name Those Adaptations

• Flamingo

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Name Those Adaptations

• Rattlesnake

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Name Those Adaptations

• Tiger

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Science is Latin for to know
So why do we do it?
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The Process of Science

• First Approach
• Discovery science
• Scientists describe some aspect of the world
• use inductive reasoning, to draw general
  conclusions

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What is Inductive Reasoning?

• Take a lot of observations and from these draw
  general conclusions
• Specific to general

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The Process of Science

• Second Approach
• Hypothesis Driven
• Use deductive reasoning
• Propose hypothesis
• Make deductions leading to predictions
• Then test hypothesis

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What is Deductive Reasoning?

• if, then statements
• From general ideas to specific observations
• Opposite of inductive

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The Scientific Method

1. Observation
2. Questions
3. Hypotheses
4. Predictions
5. Tests

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The Flying SquirrelStep 1 An Observation
When flying squirrels land on a tree they
scramble to the other side.
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Step 2 The Question

• Why do they do that? Or more specifically why do
  flying squirrels always move to the opposite side
  of the tree when they land?

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Step 3 Hypothesis
Squirrels move around tree to prevent predation
Alternative Hypothesis Move around tree to avoid
bright moonlight.
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Hypothesis

• Tentative answer to a question
• An educated guess

Alternative Hypothesis

• Another possible explanation or answer to a
  question

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Step 4 Predictions

• If squirrels move around the tree to avoid
  predation, then squirrels that do NOT move will
  be preyed on and those that do move will not be
  preyed on.
• If the squirrel move around tree to avoid light
  then if we observe them landing on the dark side
  they should NOT move.

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Step 5 The Tests

• Ideas?

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Results

• Predation Experiment
• No difference in predation rate between squirrels
  that land on one side of the tree and move and
  squirrels that do not move

Do our results support or falsify our hypothesis?
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Results

• Light Experiment
• We find that when we watch squirrels landing on
  both light and dark sides of the tree, those that
  land on the light side scramble to other side,
  those on the dark side dont

Squirrels move around tree to avoid light
Original hypothesis
Do results support or falsify our hypothesis?
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Steps of the Scientific Method
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