Populational Level
Population
Spices
Community
Ecosystem
Biosphere (Earth)
Populational level = Population
Describe the 7 key characteristics of life (from atoms to organisms to the population)
- Composed of cells
- Complex and ordered
- Respond to their environment (stimuli)
- Can grow, develop, and reproduce
- Obtain and use energy
- Maintain internal balance (homeostasis)
- Allow for evolutionary adaptation
Explain the relationship between the hierarchical organization and emergent properties
Emergent Properties result from the interaction of chemical and biological components that emerge as you go up the hierarchial organization.
*With each Step Upward in the biological hierarchy, new properties emerge that were not present at the simpler organizational levels.
Describe the scientific approach to studying nature
Science aims to understand the natural world through observation and reasoning.
Describe how scientific experiments are designed by giving an example of an experiment. Describe correctly use and explain the following terms: Observation, hypothesis, prediction, variable ( dependent and independent), controlled (standardized) variables, control group, experimental or test group, and conclusion. (Much of this will come from week 1 of lab)
Observation, questions, and hypothesis
Hypothesis is possible explanation for an observation or how something works.
Prediction is what happens in a given situation if your hypothesis is correct
Variable is the factor suggested as the cause in the prediction
Controlled variables you try to keep at an constant (s)
Control group have variables that are NOT altered
Experimental or test group have variables that are altered
Conclusion
What does the term theory mean to scientists?
A theory is the highest ranking of scientific idea to exist ( ex. The Theory of Evolution)
Distinguish between prokaryotes and eukaryotes
Prokaryotic Cell:
1. “Studio apartment” of cells
- Small, one room
- Archaea & bacteria
Eukaryotic Cell:
1. “3 bedroom/2 bathroom house”
- Has many organelles/compartments
- Bigger and more complex than prokaryotic cells
- Eukarya
List the domains and distinguish among the six kingdoms
3 Domains of life (General)
1. Eukarya: Eukarya Cells
- Archaea*: Similar to bacteria
- Bacteria*
6 Kingdoms of Life (Specific)
1. Plantae
- Fungi
- Animalia
- Protista
- Arachaea*
- Bacteria*
* Both a domain and a kingdom (prokaryotic cell)
Hypothesis
A hypothesis:
- Must be tested to determine its validity
- Is often tested in many different ways
- Allows for predictions to be made
- Must be testable and falsifiable
Iterative- hypothesis can be changed and refined with new data
Prediction
- Provide a way to test the validity of hypotheses
- The hypothesis must be rejected if the experiment produces results inconsistent with the predictions
- The more experimentally supported predictions a hypothesis makes, the more valid the hypothesis
- Results either support or don’t support (They don’t “Prove” or “Disprove”
Variables: Dependent and Independent
Dependent variable is the factor that is measured or counted ( “the outcome variable”)
Independent variable is the factor under study
Theory
A theory is respected and generally considered to be “true” if it has been continually tested but never falsified
Theories are underlying principles of science that are sustained by many different lines of evidence and have never been proven false through repeated sets of prediction and experimentation
7 Characteristics of all living organisms
- Composed of cells
- Complex and ordered
- Respond to their environment
- Can grow, develop and reproduce
- Obtain and use energy
- Maintain internal balance
- Allow for evolutionary adaptation
Cellular level
Atoms, molecules. organelles, cells
Cells is the basic unit of life
Organismal level
Tissues, organs, organ systems, organism
Experiment
Testes the hypothesis
Must be carefully designed to test only one variable at a time
Consists of a test experiment and a control experiment
Philosophical approaches to science
Reductionism
To break a complex process down to its simpler parts
Systems biology
Focus on emergent properties that can’t be understood by looking at simpler parts
Darwin and Evolution
Example of how scientist develops hypothesis and theory gains acceptance.
30yrs of observation and study before publishing: On the Origin of Species by Means of Natural Selection.
Darwin first to propose evolution (living things have changed over time)
Darwin contribution was the mechanism of Natural Selection
Thomas Malthus
Darwin studied his book: An Essay on the Principle of Population
Populations of plants and animals increase geometrically
Humans can only increase their food supply arithmetically
Populations of species remain constant because death limits population numbers
Fossil Record
Transitional forms have been found at predicted positions in time
Earth’s Age
Physicists of Darwin’s time were wrong. The Earth is 4.5 billion years old
Comparative Anatomy
Vertebrate forelimbs all share the same basic array of bones
Homologous same evolutionary origins but now differ in structure and function
Analogous structures of different origin used for the same purpose (butterfly and bird wings)
Molecular Evidence
Compare genomes or proteins of different organisms
Phylogenetic trees based on tracing origin of particular nucleotide changes to reconstruct an evolutionary history
Cell Theory
All organisms composed of cells
Cells are life’s basic units
All cells come from preexisting cells
Molecular basis of inheritance
Deoxyribonucleic Acid (DNA)
Sequence of 4 nucleotides encode cell’s information
Gene- discrete unit of information (single set)
Genome- entire set of DNA instructions
Continuity of life depends on faithful copying of DNA into child cells
Evolutionary conservation
All organisms today descended from a simple creature 3.5 BYA
Some characteristics preserved- use of DNA
Conservation reflects that they have a fundamental role
Cells
Cells are information- processing systems
Information in DNA used to direct synthesis of cellular components. Control of gene expression leads to different cells/tissue types
Cell process environmental information. Glucose levels, presence of hormones
Cells in multicellular organisms must coordinate with each other
Nonequilibrium State
Living systems are open systems
Constant supply of energy needed
Self-organizing properties at different levels
Emergent properties from collections of molecules, cells, and individuals
Describe the 3 levels of biological organization
- Cellular level
- Organismal level
- Populational level
Describe the Cellular Level of biological organization
Atoms ( ex: C, O, N, M)
Molecules (ex: H2O)
Macromolecules (ex: DNA C6H12O6)
Organelles ( “little organs,” ex. mitochondria)
Cells
*Cellular= Cells
Smallest——————————————Largest
Describe the Organismal Level of biological organization
Tissues ( groups of cells working together for the same purpose ex: Nerve cells)
Organs (ex: brain)
Organ System ( ex: the nervous system)
Organism (ex: cat)
Organismal= Organ
Smallest——————————————Largest
6 steps in scientific study
- Observation
- Form a question
- Form a hypothesis
- Conduct an experiment
- Analysis data
- Conclusion
Natural Selection
Living creatures with favorable traits are more likely to reproduce. And pass favorable traits to the next generation. To help survive in their environment.