A View of Life

1. A View of Life

2. The Human Genome Project mapped the complete set of human genes • Genomics analyses the DNA sequence of an organism • While genomics will lead to breakthroughs in science, it also raises ethical concerns • Safeguarding the privacy of genetic information, for example

3. Living organisms composed of cells • Unicellular organisms • Single cell • Multicellular organisms • Many cells organized to form tissues, organs, and organ systems

4. Cells • Plasma membrane regulates passage of materials • Specialized molecules (usually DNA) contain genetic instructions • Internal structures called organelles perform specific functions

5. Types of cells • Prokaryotic cells, exclusive to bacteria and microscopic organisms • Eukaryotic cells contain a variety of organelles, including a nucleus, which houses DNA

6. Biological growth • Increase in the size of cells, the number of cells, or both • Development • Includes all the changes that take place during an organism’s life • Structures and body form are adapted to an organism’s functions

7. Metabolism processes • Chemical reactions and energy transformations • Essential to nutrition, growth and repair of cells, and conversion of energy • Regulation of metabolic processes maintains homeostasis

8. Stimuli • Physical or chemical changes in the internal or external environment • The organism responds to, for example, changes in • Light • Temperature, pressure, or sound • The chemical composition of soil

9. Locomotion • Simpler organisms • Amoeboid movement • The beating of cilia or flagella • Animals • Move by contracting muscles • Some are sessile and have cilia or flagella • Plants respond to light, water, etc.

10. Asexual reproduction and sexual reproduction

11. Adaptation • Populations evolve to better survive • Adaptations • Characteristics that enhance an organism’s ability to survive in a particular environment • May be structural, physiological, behavioral, or a combination

12. The hierarchyof biologicalorganizations

13. The cell • Consists of atoms and molecules • Is the basic unit of life • In multicellular organisms, associates to form tissues

14. Tissues • In animals, an example is muscle • In plants, an example is epidermis • Tissues are organized into organs • Tissues and organs form organ systems

15. Population • Members of a species that live in the same area at the same time • Community • Populations that live together and interact • Ecosystem • A community and the environment

16. To carry on life processes, an organism must have • Precise instructions • Communication among cells • This information is coded and delivered by • Chemical substances • Electric impulses

17. DNA is the large molecule that makes up genes • Genes specify instructions for making every living organism • Watson and Crick worked out structure of DNA in 1953

18. DNA consists of twochains of atomstwisted into a helix

19. DNA contains “recipe” for proteins • Proteins determine structure and function of cells and tissues

20. In multi-cellular organisms, communication with and among cells is critical • Some proteins are important in this communication • Cell-to-cell communication is a complex process called cell signaling

21. Information transmitted from one part of the body to another is important in regulating life processes • Information is transmitted by • Hormones • Neurotransmitters and their receptors

22. Evolution is the unifying concept of biology • Biology • Hierarchical classification scheme • Identifies the approximately 1.7 million species of living organisms

23. Systematics studies the diversity of organisms and their evolutionary relationships • Taxonomy is the science of naming and classifying organisms

24. Binomial system of nomenclature • Developed in the 18th century by Linnaeus, a Swedish botanist • Names and classifies organisms • Basic unit is a species • Each species assigned a two-part name

25. Binomial system of nomenclature uses a series of taxonomic categories from species to domain

27. Each category is more general andmore inclusivethan the onebelow it

28. Natural selection • Theory of evolution developed by Darwin and Wallace • The Origin of Species by Natural Selection published in 1859

29. Natural selection based on four observations • Members of a species show variation • Organisms produce many more offspring than will survive • Organisms compete • Only some survive to reproduce

30. Egg masses of the wood frog— Many more produced thancan survive

31. Variation among individuals • Result of different varieties of genes that code each characteristic • Ultimate source of variation is random mutation • Chemical or physical changes in DNA that can be inherited • Modifies genes

32. Every cell of an organism requires nutrients • Certain nutrients are used as fuel for cellular respiration • Virtually all cells carry on cellular respiration

33. A self-sufficient ecosystem contains three types of organisms • Producers • Consumers • Decomposers

34. Ecosystems depend on continuous input of energy • Organisms can neither create energy nor use it with complete efficiency • During every energy transaction, some is lost to the environment as heat

35. Energy flow

36. The scientific method involves systematic thought • Deductive reasoning draws conclusions from premises • Inductive reasoning begins with observations and draws conclusions or extrapolates

37. The scientificmethod involvesordered steps • Hypothesis • Method • Results • Conclusion