Introduction to Biology

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Introduction to Biology

  1. 1. Biology in the21 Century st
  2. 2. The Study of Life Biologists study life in all its forms Earth is Home to an Incredible Diversity of Life!
  3. 3. The Biosphere All living things and all the places they are found on earth
  4. 4. Biodiversity The variety of life Why is biodiversity greater closer to the equator?  More living things are able to survive in consistently warm temperatures than in areas that have changes in temperature
  5. 5. Species A particular type of living things that can reproduce by interbreeding among themselves  About 2 million species have been identified, but biologists estimate that over 10 million remain to be discovered  Every year about 10,000 new species are identified!
  6. 6. OrganismAny individualliving thingAll organisms share certain characteristics
  7. 7. Characteristics of Life Cells Need for energy Response to environment Reproduction and development
  8. 8. Cells All organisms are made up of one or more cells A cell is the basic unit of life
  9. 9. Need for Energy Energy is the ability to cause a change or to do work The form of energy used by all living things is chemical energy Animals get their energy by eating other organisms Metabolism – the chemical processes that build up or break down materials
  10. 10. Response to Environment Light, temperature, and touch are just a few of the physical factors to which organisms must respond. These factors are called stimuli
  11. 11. Reproduction & Development Members of a species must have the ability to produce new individuals. In all organisms, the genetic material is DNA The process of development allows organisms to mature and gain the ability to reproduce
  12. 12. Unifying Themes of Biology
  13. 13. All Levels of Life Have Systems of Related Parts A system is an organized group of related parts that interact to form a whole Two organisms that interact can also be a system
  14. 14. Structure & Function areRelated in Biology What something does (function) in an organism is directly related to its shape or form (structure) Example: You bite with your sharp front teeth and chew with your molars
  15. 15. Organisms Must MaintainHomeostasis to Survive inDiverse Environments While environmental conditions change, the conditions inside organisms usually stay stable Homeostasis is usually maintained through negative feedback, a change in a system causes a response that tends to return that system to its original state
  16. 16. Evolution Explains theUnity and Diversity of Life Evolution is the change in the genetic makeup of a subgroup of a species over time It occurs through natural selection of adaptations.
  17. 17. Science is a way of thinking,questioning, and gathering evidence
  18. 18. There is no single “scientific method”but investigations tend to havecommon stages:  Collecting Observations  Asking Questions  Forming Hypotheses and Making Predictions  Confirming Predictions  Drawing Conclusions  Viewing Conclusions in Context
  19. 19. Observation the act of noting or perceiving objects or events using the senses
  20. 20. Forming a Hypothesis HYPOTHESIS – an educated guess based on what is already known Must be backed up by fact PREDICTION – expected outcome of a test, assuming the hypothesis is correct
  21. 21. EXPERIMENT – a plannedprocedure to test a hypothesis  CONTROL GROUP – a group in an experiment that receives no experimental treatment  EXPERIMENTAL GROUP – a group that receives experimental treatment Control and experimental groups are identical except for one variable!
  22. 22. Variables in an ExperimentINDEPENDENT DEPENDENT VARIABLE – the VARIABLE – the one factor that variable that is is changed in an measured as a experiment result of the change in the independent variable
  23. 23. Drawing Conclusions• Once data are collected and analyzed, a conclusion is made as to whether the data support the hypothesis.• The hypothesis may be supported or rejected.• A hypothesis can be supported, but never proven because another experiment with new data and new information may alter the conclusion.• Many experiments must be performed in order for a hypothesis to be proven correct.

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