Exploring Life's Levels: From Global to Microscopic Scale

1. Created by Roxanne Leitner

2. CONCEPT 1.1 Biology explores life from the global to the microscopic scale. Objectives • Identify the major organizational levels of life.

3. Key Terms biosphere ecosystem organism cell DNA gene CONCEPT 1.1 Biology explores life from the global to the microscopic scale.

4. Biosphere • all parts of the planet that are inhabited by living things • atmosphere • lithosphere • hydrosphere

5. Flying foxes are becoming an endangered species, partly because of habitat destruction

6. Life in the Trees • The lives of gray-headed flying foxes are closely entwined with the lives of the eucalyptus trees that form their habitat • Eucalyptus trees provide food and roosting sites for the flying foxes • Flying foxes aid in eucalyptus pollinationand help disperse the resulting seeds

7. The Scope of Biology • Biology is the scientific study of life • Interactions between different kinds of organisms affect the lives of all

8. Life’s levels of organization define the scope of biology • A structural hierarchy of life, from molecules to ecosystems, defines the scope of biology • An ecosystem consists of: • all organisms living in a particular area • all nonliving physical components of the environment that affect the organisms (soil, water)

9. Ecosystems include: • all the organisms in an area, which make up a community • interbreeding organisms of the same species, a population ECOSYSTEM LEVELEucalyptus forest Ecosystem COMMUNITY LEVELAll organisms ineucalyptus forest POPULATION LEVELGroup of flying foxes ORGANISM LEVELFlying fox Brain Spinal cord ORGAN SYSTEM LEVELNervous system ORGAN LEVELBrain Nerve TISSUE LEVELNervous tissue CELLULAR LEVELNerve cell MOLECULAR LEVELMolecule of DNA Figure 1.1

10. Organisms are made up of: Organism ECOSYSTEM LEVELEucalyptus forest COMMUNITY LEVELAll organisms ineucalyptus forest • organ systems • organs • tissues • cells • molecules • atoms POPULATION LEVELGroup of flying foxes ORGANISM LEVELFlying fox Brain Spinal cord ORGAN SYSTEM LEVELNervous system ORGAN LEVELBrain Nerve TISSUE LEVELNervous tissue CELLULAR LEVELNerve cell MOLECULAR LEVELMolecule of DNA Figure 1.1

11. Concept Check 1.1 • Which level of life includes all of the other levels in this list: organisms, cells, biosphere, molecules, ecosystems? Explain your answer. biosphere • Identify an ecosystem in the area where you live?

12. Concept Check 1.1 • What are genes? How are they related to DNA? genes – units of inherited information part of DNA molecule

13. CONCEPT 1.2 Biology explores life in its diverse forms. Objectives • Use the term species in discussing life’s diversity. • Explain the basic strategy biologists use in classifying organisms. • Identify a characteristic that separates the domains Bacteria and Archaea from the domain Eukarya.

14. Key Terms species domain unicellular prokaryotic cell eukaryotic cell multicellular CONCEPT 1.2 Biology explores life in its diverse forms.

15. Classifying Life: The Basic Idea taxonomy • study of classification species • organisms that look alike, can interbreed & produce fertile offspring

16. Levels of Classification • Kingdom • Phylum • Class • Order • Family • Genus • Species

17. Three Domains • unicellular • prokaryotic cells – without nuclei or membrane-bound organelles • Domain Bacteria • Typical bacteria • Domain Archaea • live in harsh environments Figure 1.4A, B

18. 3. Domain Eukarya • unicellular or multicellular • eukaryotic cells • nucleus • membrane-bound organelles • Kingdoms • Protista • Fungi • Plantae • Animalia Figure 1.4C-F

19. Concept Check 1.2 • Explain the relationship between the terms species and organism. • Explain two different ways that you could classify the following items: banana, lemon, sandwich, milk, orange, meatball, salad.

20. Concept Check 1.2 Explain the main difference between organisms of the domains Bacteria and Archaea and organisms of the domain Eukarya. Bacteria, Eukarya – prokaryotes Eukarya - eukaryotes

21. CONCEPT 1.3 Ten Themes unify the study of life. Objectives • Identify the themes of biology.

22. Key Terms systems photosystem producer consumer homeostasis adaptation population natural selection evolution CONCEPT 1.3 Ten Themes unify the study of life.

23. Unity in diversity: All forms of life have common features • All organisms share a set of common features, signs of unity in life’s vast diversity • All are made of cells • All have DNA as their genetic blueprint • These orchids show the variety possible within one species Figure 1.5A

24. DNA is made of chemical units called nucleotides • Each species has its own nucleotide sequence Figure 1.5B

25. The genetic information in DNA underlies all of the features that distinguish life from nonlife • Order and regulation • Growth and development • Use of energy from the environment • Response to environmental stimuli • Ability to reproduce • Evolutionary change

26. Evolution explains the unity and diversity of life • Charles Darwin is a central figure in biology • He synthesized the theory of evolution by natural selection • A theory in science is a comprehensive idea with broad explanatory power • Evolution is the core theme of biology Figure 1.6A

27. The theory of natural selection explains the main mechanism whereby all species of organisms change, or evolve Natural Selection (1) Population with varied inherited traits (2) Elimination of individuals with certain traits (3) Reproduction of survivors Figure 1.6B

28. Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the success of some individuals over others • Natural selection is the editing mechanism • Evolution is based on adaptations

29. Concept Check 1.3 • Using examples describe three biology themes. • Describe four ways you have interacted with your environment today.

30. Concept Check 1.3 In biological terms are you a producer or consumer? Explain your answer.