![Page 1: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/1.jpg)
Chapter 4 Lecture Notes
Ecosystems: How They Change
![Page 2: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/2.jpg)
Outline of Chapter 4
A. Population dynamics
B. Population equilibrium
C. Evolution
D. Succession
E. Living beyond our means
![Page 3: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/3.jpg)
Dynamic Equilibrium
Ecosystems are constantly changing in order to stay balanced.
![Page 4: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/4.jpg)
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
![Page 5: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/5.jpg)
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
![Page 6: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/6.jpg)
Primary succession•Must create new soil for plants to grow•The first plants to come in are called pioneer species
![Page 7: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/7.jpg)
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- blueprintRNA- carpenterProtein- house, pieces, wood
![Page 8: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/8.jpg)
Each cell in an organism has the instructions.
![Page 9: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/9.jpg)
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?
![Page 10: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/10.jpg)
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.
![Page 11: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/11.jpg)
Speciationexample
Reproductive Isolation
![Page 12: Chapter 4 Lecture Notes Ecosystems: How They Change](https://reader035.vdocuments.net/reader035/viewer/2022062720/56649f155503460f94c29ec2/html5/thumbnails/12.jpg)
Understand how molecular biology (micro) relates to evolutionary change (macro) for
each of these vocabulary words:1. Adaptation2. Genetic variation3. Gene pool4. Differential reproduction5. Biological evolution6. Selective breeding7. Artificial selection8. Selective pressure9. Natural selection10. Fitness11. Evolution of a new species12. Reproductive isolation