This chapter includes contents: Population dynamic: S/J curve, introduced species (example: Rabbits and American Chestnut), predator- prey and host-parasite dynamics, population equilibrium, evolution, succession, living beyond our means. | Chapter 4 Lecture Notes Ecosystems: How They Change Outline of Chapter 4 Population dynamics Population equilibrium Evolution Succession Living beyond our means Dynamic Equilibrium Ecosystems are constantly changing in order to stay balanced. S- and J- curves, Biotic potential vs. Environmental Resistance, Critical number, Predator-Prey relationships, keystone species, competition, introduced species Succession - One species gradually replaced by another in an ecosystem primary – new ecosystem where there were no living things before. Cooled lava, receded glacier, mud slide secondary- ecosystem used to be there. Fire, humans clear an area Aquatic – (type of secondary) lakes taken over by terrestrial ecosystem Climax ecosystem- in balance only changes if major interference Fires in Ecosystem Maintain balance of species and energy in ecosystems over the long run. Beneficial b/c provide nutrients for soil We avoid natural fires, but the problems like Crown Fires- (not natural) kill the whole tree 1988 Yellowstone fires changed climax ecosystems of white bark pine trees to huckle berries. Grizzlies ate both Primary succession Must create new soil for plants to grow The first plants to come in are called pioneer species The Basics of Evolutionary Change Vocabulary * DNA * Chromosome (46) * Gene –Coding region of the DNA * allele (23) – during meiosis, each egg or sperm receives one allele for each gene Central Dogma: DNA- blueprint RNA- carpenter Protein- house, pieces, wood Each cell in an organism has the instructions. Mutations Mutations are changes in DNA. They can occur by: * Normal variation * Chemical * UV * Radiation Genetic Trait- only passed down if an organism reproduces Good or Bad? Why do species change? Selective pressure on DNA mutations from environmental resistance and biotic potential The time and space for evolution can be understood by knowing how old the earth is, how long life has been around, and Pangea. Speciation example Reproductive Isolation Understand how molecular biology (micro) relates to evolutionary change (macro) for each of these vocabulary words: Adaptation Genetic variation Gene pool Differential reproduction Biological evolution Selective breeding Artificial selection Selective pressure Natural selection Fitness Evolution of a new species Reproductive isolation Chapters 3 and 4 Group Assignment: Research your topic and be prepared to explain the main points of that topic to your classmates tomorrow in a 2-3 slide, less than 5 minute PPT presentation. Include information beyond that found in our textbook. Introduce yourselves Provide examples Include at least one visual (other than the figures) Define vocabulary (check the study guide) Deposit into: teacher inbox/Griffith /APES/Ch 3,4 PPT/your period as “#1 Griffith,Griffith” Rubric for presentation 5 points good group practices 5 points content correct 2 points thorough 2 points on time (4-5 minutes) 1 point GREAT, impressive, good ideas for remembering the materials 15 points possible Group Topics Productivity of Ecosystems Figs 3-14, 3-22 Energy flow, biomass pyramid figs 3-15 Ecosystem Capital Table 3-2 Population interactions and curves figs 4-2, 4-5, 4-6 Biotic potential vs. environmental resistance and critical number fig 4-4 Keystone species fig 4-7 Introduced species figs 4-11, 4-12, 4-13 Geological time scale (earth, life, human perspective) Pangaea and tectonic plates fig 4-19 Interesting adaptations fig 4-15 Aquatic succession Fig 4-22
