Explain what community structure is.
1. what species are in a community
2. What is their relative abundance
3. What are the relationships among the species
How do you calculate Simpson's diversity index?
A fraction with 1 in the numerator and the sum of the squared relative abundances
(ex. (0.54)2+(0.24)2...) in the denominator
How do you calculate Shannon's diversity index?
The sum of the relative abundances multiplied by that same relative abundance "lawned"
ex. (0.24)(ln 0.24)+(0.16)(ln 0.16)....
Discuss four (local-scale) reasons why one community might have more species than another.
- Productivity (resources)
- Habitat diversity
- Keystone species
- Disturbance (logging, trampling, natural disasters...)
Describe the intermediate disturbance hypothesis (IDH)
Communities that experience more disturbance have greater diversity
What is a guild?
Organisms that feed on similar items (frugivore, seed-eaters, grazers...)
What is the difference between primary and secondary succession
Primary starts from scratch (volcano, no soil or dead soil) while secondary has soil that may or may not have seeds (but no plants)
Explain facilitation in succession
One species promotes the survival of another
Explain inhibition in succession
One species inhibits the survival of another
How do you calculate Jaccard’s index of similarity across 2 communities?
A fraction where the numerator is the amount of species present in both communities and the denominator is the sum of The number of species in community A, the number of species in community B and the number of species in both.
Ex. X/A+B+X expressed as a decimal
Define primary productivity
The rate at which solar/chemical energy is captured and converted into chemical bonds by photosynthesis/chemosynthesis
Define standing crop
Biomass of producers present in an ecosystem at a given time and area
How are net and gross primary productivity related?
NPP=GPP-respiration
NPP is the productivity possible with the amount of GPP after respiration
What percentage of solar energy is captured by plants in photosynthesis?
1%
What percentage of captured solar energy is made into more plants?
40%
Describe 4 methods ecologists can use to measure NPP.
- Biomass of producers at beginning and end of growing season
- Carbon dioxide (uptake and release)
- Oxygen (uptake and release)
- Remote sensing
what factors limit NPP
- Temp
- Precip
- Nutrients
- Light
where in the world NPP is highest
in terrestrial and aquatic ecosystems
The coast and the rainforest
What is assimilation efficiency?
Percentage of consumed energy that is assimilated (goes to respiration or growth)
What is ecological efficieny?
Percentage of net production of one trophic level compared to the next level down
What are the 7 major nutrients?
- nitrogen
- phosphorus
- sulphur
- potassium
- calcium
- magnesium
- iron
What are some examples of nitrogen use in the body?
amino acids, nucleic acids
What are some examples of phosphorous use in the body?
bones, scales, teeth, DNA, ATP, RNA
What are some examples of sulfer use in the body?
Proteins
What are some examples of potassium use in the body?
Enzymes
What are some examples of calcium use in the body?
bones, teeth, muscle contraction
What are some examples of magnesium use in the body?
many enzymes, chlorophyll
What are some examples of iron use in the body?
hemoglobin, needed to make chlorophyll
What are the 5 processes in the hydrological cycle?
Evaporation, transpiration, precipitation, infiltration, run-off
Describe what the bacteria in the root nodules of legumes are doing when they fix nitrogen
Nitrogen gas in the atmosphere gets converted into bioavailable forms
Give three examples of a legacy effect
- Esker
- Fire history
- Abandoned agricultural fields
- Glaciers
- Historic ocean levels
Compare alpha, beta, and gamma diversity, and explain how each is related to the other.
Alpha- subset of species in a region that can live at a particular site
Gamma- all the species in a region
Beta- number of species that differs between two habitats
All methods of comparing species diversity
What is the concept of perfect nestedness?
A bunch of smaller patches only have species that a bigger patch has
Summarize the Equilibrium Theory of Island Biogeography in your own words
The closer the island is to the mainland and the bigger the island is the more species it will have.
Say approximately how many species on earth have been named by humans, and how many in total are estimated to live on earth?
1.3 million described, most scientists estimate 10 million species total
Define mass extinction
at least 75% of all species go extinct over 2 million years
Most recent mass extinction?
Extinction of the dinosaurs, 65 million years ago
Discuss what proportion of species in various taxonomic groups are threatened globally and in Canada.
Globally, amphibians and fish. In Canada, amphibians