The Science of Biology Chapter 1. 2 What are the Properties of Life? Living organisms: Cellular...
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Transcript of The Science of Biology Chapter 1. 2 What are the Properties of Life? Living organisms: Cellular...
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What are the Properties of Life?
Living organisms:Cellular organization- composed of cellsOrdered complexity- complex and orderedSensitivity- respond to their environmentGrowth, development and reproduction- can grow and
reproduceEnergy utilization-obtain and use energyHomeostasis-maintain internal balanceEvolutionary adaptation-allow for evolutionary
adaptation
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What are the Cellular Levels of Organization?
Cellular Organization cells
organellesmolecules
atoms
The cell is the basic unit of life.
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What are the Organism Levels of Organization?
Organismal Level
organism
organ systems
organs
tissues
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What are the Population Levels of Organization?
Population Level
ecosystem
community
species
population
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What are Emergent Properties?
Each level of organization builds on the level below it but often demonstrates new features.
Emergent properties: new properties present at one level that are not seen in the previous level
For example: The information present in tissues is not present in a cell but was built on the latter.
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The Nature of Science
• Deductive reasoning • Inductive reasoning
General principles
Specific predictions of results
Specific observations
General Scientific Principles
Science aims to understand the natural world through observation and reasoning.
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How hypothesis driven science makes and tests predictions?
A systematic approach is used by scientists to gain understanding of the natural world.
-Observation-Hypothesis formation-Prediction-Experimentation-Conclusion
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How hypothesis driven science makes and tests predictions?
A hypothesis is a possible explanation for an observation.
A hypothesis
-must be tested to determine its validity
-is often tested in many different ways
-allows for predictions to be made
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How hypothesis driven science makes and tests predictions?
The experiment-tests the hypothesis-must be carefully designed to test only one variable/factor at a time-consists of a test experiment and a control experiment
If the hypothesis is valid, the scientist can predict the results and do further experiments to confirm its validity.
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Other approaches of Science to explain living systems
Reductionism (Philosophical approach) - to break a complex process down to its simpler parts
- Metabolism of cells were unraveled by understanding individual pathways and their specific enzymes.
Models – Provide a way to organize thinking about a problem that is difficult to study directly
- Shows a larger picture and how they fit together/interconnect network
- Suggests experiments that can refine or test the model
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What is Scientific Theory?
A Scientific Theory
-is a body of interconnected concepts
-is supported by scientific reasoning and experimental evidence
-explains facts in some area of study
Research done by scientists is either basic or applied.
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An example of scientific enquiry by Charles Darwin: His evidence
Similarity of related species
- Darwin noticed variations in related species living in different locations
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An example of scientific enquiry by Charles Darwin
Evolution: modification of a species over generations-“descent with modification”
Natural selection: individuals with superior physical or behavioral characteristics are more likely to survive and reproduce than those without such characteristics
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Malthus theory of population growth versus resources availability
• Population growth vs. availability of resources
- population growth
is geometric
- increase in food
supply is arithmetic
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How Darwin’s Evidence enlightened from Malthus theory?
Population growth vs. availability of resources
- Darwin realized that not all members of a
population survive and reproduce.
-Darwin based these ideas on the writings of Thomas Malthus.
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Post-Darwin Evolution Evidence
Fossil record
- New fossils are found all the time
- Earth is older than previously believed
Mechanisms of heredity
- Early criticism of Darwin’s ideas were resolved by Mendel’s theories for genetic inheritance.
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Post-Darwin Evolution Evidence
Comparative anatomy- Homologous structures have
same evolutionary origin, but different structure and function.
- Example: Forelimbs of different vertebrates responding to their evolutionary demands
- Analogous structures have similar structure and function, but different evolutionary origin
- Example: Wings of birds and butterflies
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Post-Darwin Evolution Evidence
Molecular Evidence
Increased understanding of DNA (genome) and protein (amino acid) structures has led to the development of more accurate phylogenetic trees.
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Unifying Themes in Biology
Cell theory- All living organisms are made of cells, and all living cells come from preexisting cells.
Cells process information stored in DNA as well as information received from the environment
Molecular basis of inheritance- DNA encodes genes which control living
organisms and are passed from one generation to the next.
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Unifying Themes in Biology
Structure and Function
-The proper function of a molecule is dependent on its structure.
-The structure of a molecule can often tell us about its function.
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Unifying Themes in Biology
Evolutionary change
- Living organisms have evolved from the same origin event. The diversity of life is the result of evolutionary change.
Evolutionary conservation
- Critical characteristics of early organisms are preserved and passed on to future generations.
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Unifying Themes in Biology
Emergent properties
- New properties are present at one level of organization that are not seen in the previous level
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