Great Ideas in Science Lecture 10 - Living Things

1. Great Ideas in Science Lecture 10 - Living Things Prof. Robert Hazen UNIV-301

2. Every Living thing… • Can be classified in one scheme • Is modular – composed of a few simple molecules • Is made of cells – life’s chemical factories • Uses the same genetic code • Evolved from a first cell by natural selection • Lives in ecosystems of many interdependent organisms

3. Ways of Thinking About Living Things • Biosphere • Ecosystem • Community • Population • Organism • Anatomy & physiology • Cellular • Molecular

4. What is Life? • Encapsulation: All life is separated from the environment by a membrane. • Metabolism: All life obtains energy and atoms from the environment. • Reproduction: All life reproduces via genetics.

5. The Characteristics of Life • High degree of order and complexity • Part of larger systems of matter and energy • Life depends on chemical reactions in cells • Life requires liquid water • Organisms grow and develop • Regulate energy use • Share same genetic code, code is heritable • All living things are descended from a common ancestor

6. Great Idea: Living things use many different strategies to deal with the problems of acquiring and using matter and energy. • Linnaean classification • Hierarchy • Kingdom • Phylum • Class • Order • Family • Genus • Species

7. Why is Taxonomy Important? Think about how to describe a tree. Names are essential for accurate communications But taxonomy can be rather arbitrary • Lumpers versus splitters • Local variations in species

8. Why is Taxonomy Important? Dracorex (top left) and Stygimoloch (top right), as growth stages of Pachycephalosaurus (bottom).

9. Why is Taxonomy Important? C A B

10. Classifying Life • Kingdoms • Monera • Protista • Fungi • Plants • Animals

11. Taxonomy of Animals

12. Classifying Human Beings • Kingdom: Animals • Phylum: Chordates • Subphylum: vertebrates • Class: Mammals • Order: Primates • Family: Hominid • Genus: Homo • Species: sapiens

13. A New View:Three Domains of Life • Bacteria • Archaea • Eukarya

14. Implications of Linnaean Classification • You can use genetic material. • Similarities depend on time and change. • Classification results from real events. “Nothing in biology makes sense except in the light of evolution.”

15. Strategies of Fungi • Growth • Filaments • Decomposers • Structure • Mass of filaments • Many forms • Reproduction • Break filaments • Spores (usually asexual) • Lichens • Fungi + Algae • Two interdependent species

16. The Simplest Plants • Phylum: Bryophytes • Structure • No roots • Photosynthetic • Reproduction • Sexual • Asexual

17. Vascular Plants • Phylum: vascular plants • Structure • Roots, stems, leaves • Control water loss • Reproduction • Spore = fertilized egg • Cone = holds egg or sperm • Seed = egg plus nutrients • Pollen = sperm • Strategies • Seedless (Ferns - spores) • Seeds but no flowers (Gymnosperms - cones) • Seeds and flowers (Angiosperms)

18. Angiosperms

19. Invertebrates • No backbone • Most diverse animals • Arthropods • 70% of known animal species • Structure • Exoskeleton • Jointed legs

20. The Molecules of Life All life is modular – composed of a few simple molecules.

21. Key Ideas about the molecules of life • Based on Carbon (Organic chemistry) • Six main elements (CHNOPS) • Modular; built from simple units • Molecular shapes determine their function

22. Nutrition Facts • Lipids • Sugars • Amino acids • Energy

23. Carbohydrates (sugars) Carbon Hydrogen Oxygen

24. Cellulose and Starch

25. Lipids

26. Saturated and Unsaturated Lipids

27. Amino Acids • Amino group • Carboxyl group • Side-group (20 different things)

28. Protein – sequence of amino acids • Primary – chain of amino acids • Secondary – folding of chain • Tertiary • Quaternary

29. Proteins • Structural role

30. Proteins – Enzymes

31. Dietary Amino Acids