ecology
DESCRIPTION
Ecology. Chapter 50. Biotic Factors Abiotic Factors. Chapter 50. Subfields of ecology Population : studies interactions between individuals of a population Ex? Community : studies interactions between individuals of different populations Ex? - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/1.jpg)
Ecology
![Page 2: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/2.jpg)
Chapter 50
• Biotic Factors• Abiotic Factors
![Page 3: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/3.jpg)
Chapter 50
• Subfields of ecology– Population: studies interactions between individuals
of a population• Ex?
– Community: studies interactions between individuals of different populations• Ex?
– Ecosystem: studies interactions between the community and abiotic factors• Ex?
![Page 4: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/4.jpg)
Chapter 52• Exponential growth model– N=• Population size
– B=• Birth rate… number of births per population size (per
capita)– D (sometimes called M)=• Mortality rate.. Number of deaths per population size
– r = rate of increase (growth rate)• Per capita birth – per capita mortality
– Equation for exponential growth• dN/dt = rmaxN
![Page 5: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/5.jpg)
Population growth = r x N,r = b – d (per capita)
![Page 6: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/6.jpg)
Notice: r is constant, but population size curve gets steeper as N changes = J-shaped curve
Characteristic of:• Some organisms in
a new environment• N reduced by
catastrophe, now recovering
![Page 7: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/7.jpg)
Carrying Capacity (K)
• As the population grows, at some point resources become limiting
• K= max. population size the environment can sustain– Not fixed, changes with resource availability
![Page 8: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/8.jpg)
![Page 9: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/9.jpg)
Growth Rate Slows as N approaches K
![Page 10: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/10.jpg)
Carrying Capacity
![Page 11: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/11.jpg)
Allee effect
• In the logistic model, an assumption is that each individual added has the same negative effect on growth rate – but….
• Some populations show the Allee effect – when a population falls too low, some aspect of survival or reproduction is harmed– Cross pollination in plants– Finding a mate– Protection from the wind from a stand of trees
![Page 12: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/12.jpg)
• Density dependent limiting factors:
• Density independent limiting factors:
![Page 13: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/13.jpg)
• K-selected life history strategy (energy and..) – – Have adaptations that maximize success at high population density
• Maximize efficient use of resources• Typically fewer, larger offspring with parental care• Larger body• Longer life span
• R-selected life history strategy-– Have adaptations that maximize success at low population density
• Rapid reproduction- numerous small offspring• Little to no parental care• Best in opportunistic species that live in fluctuating environments• Small body• Mature quickly, short life span
• Many species fall somewhere in between! But, natural selection cannot maximize for both – energy trade off
• Reproduction vs. survival• Large, cared for babies vs. many babies
![Page 14: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/14.jpg)
![Page 15: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/15.jpg)
Chapter 53 Community Ecology
• Niche: – The role a species plays in the community
![Page 16: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/16.jpg)
Competition (-/-)• Gauss’ law
![Page 17: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/17.jpg)
Resource Partitioning can lead to Character Displacement
• Individuals in both populations that can avoid competition are at an advantage• can lead to physical
changes in the population due to microevolution (character displacement)
• Example: Hawks and Owls have similar prey (rodents), but avoid competition by hawks feeding on diurnal species, and owls feeding on nocturnal species
![Page 18: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/18.jpg)
• Interaction type chart
![Page 19: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/19.jpg)
Species Richness vs. species diversity• Consider a cornfield and a woodsy area of the
same size.– Describe the differences in species richness– Describe the differences in species diversity– How do you think the same area of rainforest
would compare?
![Page 20: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/20.jpg)
Species Richness Describe possible reasoning for the phenomenon seen here.
![Page 21: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/21.jpg)
![Page 22: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/22.jpg)
Trophic Levels
![Page 23: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/23.jpg)
Reducing energy input reduces trophic levels and species richness. Researchers manipulated the amount of leaf litter provided to a tree hole community. High = natural (control), medium = 1/10 rate, low = 1/100 rate of input.
![Page 24: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/24.jpg)
![Page 25: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/25.jpg)
![Page 26: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/26.jpg)
Starfish as keystone species
When starfish were removed from the community, mussels eventually took over. They eliminated most other invertebrates and algae.
![Page 27: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/27.jpg)
Ecosystem Ecology
Chapter 54
![Page 28: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/28.jpg)
Energy flows through, nutrients cycle within
![Page 29: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/29.jpg)
Primary Production
![Page 30: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/30.jpg)
![Page 31: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/31.jpg)
![Page 32: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/32.jpg)
Limiting Factors – aquatic: light and water
![Page 33: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/33.jpg)
Energy Partitioning
![Page 34: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/34.jpg)
Energy Pyramid
![Page 35: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/35.jpg)
Biomass (Total dry wt. of organisms) Pyramid
![Page 36: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/36.jpg)
![Page 37: Ecology](https://reader034.vdocuments.net/reader034/viewer/2022051700/5681634d550346895dd3e844/html5/thumbnails/37.jpg)
Chapter 55: Human Impact and Conservation