Biology Concepts

1. Biology Concepts 1.1 What is life?

2. What is life? • Living things vs. nonliving objects: • Comprised of the same chemical elements • Obey the same physical and chemical laws • The cell is the smallest, most basic unit of all life • Familiar organisms are multicellular • Some cells independent – single-celled organisms

3. What are emergent properties? • Levels range from extreme micro to global • Each level up: • More complex than preceding level • Properties: • A superset of preceding level’s properties • Emerge from interactions between components

4. What are the basic requirements of all living things? • Three requirements • Materials and Energy • Reproduction and Development • Adaptations and Natural Selection • Energy- the capacity to do work • The sun: • Ultimate source of energy for nearly all life on Earth • Drives photosynthesis • Metabolism- all the chemical reactions in a cell • Homeostasis - Maintenance of internal conditions within certain boundaries • Acquiring nutrients

5. What are the basic requirements of all living things? • Living things detect changes in environment • Response often involves movement • Vulture can detect and find carrion a mile away • Monarch butterfly senses fall and migrates south • Microroganisms follow light or chemicals • Even leaves of plants follow sun • Responses collectively constitute behavior

6. What are the basic requirements of all living things? • Organisms live and die • Must reproduce to maintain population • Multicellular organisms: • Begins with union of sperm and egg • Developmental instructions encoded in genes • Composed of DNA • Long spiral molecule in chromosomes

7. What are the basic requirements of all living things? • Adaptation • Any modification that makes an organism more suited to its way of life • Organisms, become modified over time • However, organisms very similar at basic level • Suggests living things descended from same ancestor • Descent with modification - Evolution • Caused by natural selection

8. Biological Concepts 1.2 Taxonomy and Systematics

9. What is taxonomy? • The rules for identifying and classifying organisms • Hierarchical levels (taxa) based on hypothesized evolutionary relationships • Levels are, from least inclusive to most inclusive: • Species, genus, family, order, class, phylum, kingdom, and domain • A level usually includes more species than the level below it, and fewer species than the one above it

10. How are organisms classified?

11. What are the three domains? • Bacteria • Microscopic unicellular prokaryotes • Archaea • Bacteria-like unicellular prokaryotes • Extreme aquatic environments • Eukarya • Eukaryotes – Familiar organisms

12. What are the kingdoms? • Archaea – • Kingdoms still being worked out • Bacteria– • Kingdoms still being worked out • Eukarya • Kingdom Protista • Kingdom Fungi • Kingdom Plantae • Kingdom Animalia

13. What are scientific names? • Binomial nomenclature (two-word names) • Universal • Latin-based • First word represents genus of organism • Second word is specific epithet of a species within the genus • Always Italicized as Genus species (Homo sapiens) • Genus may occur alone (Homo), but not specific epithet

14. Biological Concepts 1.3 Scientific method

15. What is the scientific method? • Begins with observation • Scientists use their five senses • Instruments can extend the range of senses • Hypothesis • A tentative explanation for what was observed • Developed through inductively reasoning from specific to general

16. What is the scientific method? • Experimentation • Purpose is to challenge the hypothesis • Designed through deductively reasoning from general to specific • Often divides subjects into a control group and an experimental group • Predicts how groups should differ if hypothesis is valid • If prediction happens, hypothesis is unchallenged • If not, hypothesis is unsupportable

17. What is the scientific method? • Results • Observable, objective results from an experiment • Strength of the data expressed in probabilities • The probability that random variation could have caused the results • Low probability (less than 5%) is good • Higher probabilities make it difficult to dismiss random chance as the sole cause of the results

18. What is the scientific method? • The results are analyzed and interpreted • Conclusions are what the scientist thinks caused the results • Findings must be reported in scientific journals • Peers review the findings and the conclusions • Other scientists then attempt to duplicate or dismiss the published findings

19. What is a scientific theory? • Scientific Theory: • Joins together two or more related hypotheses • Supported by broad range of observations, experiments, and data • Scientific Principle / Law: • Widely accepted set of theories • No serious challenges to validity

20. What types of experimental variables are there? • Experimental (Independent) variable • Applied one way to experimental group • Applied a different way to control group • Response (dependent) variable • Variable that is measured to generate data • Expected to yield different results in control versus experimental groups