BILD 3: Final - Ecology p.2
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2 Components of Species Diversity:
- 1. Species Richness= Total # of different SPECIES
- 2. Relative Abundance= Total % or PROPORTION of each species
Species diversity increases with: (2)
- 1. Total number of species present
- 2. Relative evenness in abundance
The more ________ the distribution of species in a community, the more diverse it is
What is the Richness & Abundance of these 2 communities?
- Richness = Same (4)
- Abundance = More diverse in #1 (more even)
Commonness is _________ & rarity is ___________
Rare - Common
Common species in a community are usually _________________
(Can eat in any environment, live w/humans)
Explain Rank-Abundance Curve in person's gut:
MOST are rare; we share some of the same bacteria which are most COMMON, but the majority VARY depending on diet & initiation of gut flora.
- (Commonness is rare; rarity is common)
Places with HIGH species diveristy: _____________________
Places with LOW species diversity:
- High: Tropical Rainforest
- Low: Boreal Forest
2 key factors correlated w/community's species diversity:
- 1. Latitude
- 2. Geographic are
- Bioinformatics uses many areas of computer science, mathematics and engineering to process biological data.
- -> Uses G.I.S. = Global Information System
Latitude (& studies in species diversity):
- Latitudinal Gradients in Species Richness
- Easy to measure
- Lower latitude (0o by equator) MORE DIVERSITY
Explain how we get latitudinal gradient in biodiversity & 2 main factors:
- 2 main factors:
- 1. Solar Energy
- 2. Water Availability
- -> Heat, water, temp, precipitation, photosynthesis. Can measure rate of Evapotranspiration
The evaporation of water from soil plus transpiration of water from plants (measures amount of water leaving a plant)
High evapotransporation is positively correlated with high species _____________ .
Geographic Area (& studies in species diversity) & Species-Area Curve:
Species-Area Curve: The more area, the more species.
- Logarithmic Scale:
Dictates which species found where, based on feeding relationships.
Regularly spaced increases & decreases in population of 2 predator-prey species.
- The predator population’s fluctuations follow those of the prey population
- The prey population begins to increase while the predator population is still decreasing The predator drives the changes in the prey population (by catching and killing its members) and the prey (as the predator’s food supply) drives the predator’s
- population changes
- A lag between the population responses of
- predator and prey cause the two cycles to be out of phase with one
- Through SIZE
- Most abundant or highest biomass
- Powerful control over occurrence & distribution of other species
ex. Redwood forest
(& how they're different from dominant)
- Not always ABUNDANT but their NICHE is important to roles in the environment.
- Strong control on a community
- ex. Pizaster (sea star) Top predator that eat muscles. Muscles are very competitive & push out species in battle for space. When the Keystone Pizaster is removed, the # of species in that area greatly declines since all the muscles eat everything
Influential by causeing physical changes in the environment that affect community structure
ex. Beaver dams
Disturbance/Changes in Ecological Communities
- Removes individuals or biomass from community
- Alters some aspect of resource availability
- ex. Flood, hurricane, human-caused, in SD- FIRES
The development of communities after a disturbance.
2 Types of Ecological Succession (after a disturbance)
- 1. Primary succession
- = No soil exists when succession begins. Little nutrients, no seeds. Takes MUCH longer to recover
- ex. New oceanic island, volcano
- 2. Secondary succession
- = Nutrients & seeds present
- Quicker recovery
- ex. Fire
Successional Community Steps:
- Old -> Disturbance
- Pioneering species -> Quick growth. Weeds.
- Early Com.-> Shrubs, small trees
- Mid Com.-> More diversity
- Late Com-> Long-lived trees
- Climax Com-> Competitively superior. Trees live taller & out-compete weeds.
Ecosystem Ecology focus:
Interaction b/w living & non-living component of an ecosystem
- Energy flow & Chemical cycling:
- - Energy flows THROUGH ecosystem
- - Nutrients cycle WITHIN ecosystem
- - Biotic portion drives these 2
Global Energy Budget:
Primary production in an ecosystem is the amount of light energy converted to chemical energy (sugars) by atutotrophs
- Gross Primary Production
- Everything that turns into biomass
- Net Primary Production
- GPP - Energy used for respiration
- *Only NPP is available to consumers
- Can measure what is left, change over time tells you flow in energy
NPP that transfers to next trophic level is generally _________.
Limits on length of food chains:
- Food chains/webs only 2 -7 trophic levels
- So much energy lost up food chain, not enough left to support more levels
Highest terrestrial NPP?
= Rainforest, Amazon, Papua New Guinea, Coral Reef, coastline
Highest marine NPP?
= Middle of ocean, doesn't cycle nutrients of the dead
Mass of carbon/area/time Equation:
- (gC/m2/yr)= mass of carbon/area/time
- Only small fraction of solar energy actually strikes photosynthetic organisms
NPP Total Area equation
(g/m2/yr)x% earth's surface area= TOTAL NPP
What happens to Matter in an Ecosystem?
Matter in the form of nutrients, cycle w/in & among ecosystems & the biosphere. Human activities are altering these chemical cycles.
Nutrients that Cycle in the Biosphere:(Hydrologic cycles)
HOW do nutrients move through ecosystems?
- From non-living to living reservoir, stays for different periods of time
How humans have altered the carbon cycle:
- Increasing carbon in atmosphere
- Burning coal, oil, gas
- Poluution releases 60 million tons of CO2 into the air PER DAY
What is the impact of increased carbon?
- CO2 is a greenhouse gas
- Trapping heat in atmosphere
- Increasing global temp
Main ways humans release carbon into atmosphere:
- (Transportation uses carbon stored in the ground)
Conservation Biology's main goal is to ______________________________.
Preserve the variation of life
Many fields involved in Conservation Biology..
- Evoliutionary Biology
- Molecular Biology
- Behavioral Ecology
- Political Science
- Urban/Rural Planning
3 Levels of Biodiversity:
- 1. Genetic -> Variation is the FUEL for evolution/adaptation
- 2. Species
- 3. Ecosystem -> GREATEST EFFECT to blanket all 3
- ex. Protect spotted owl by stopping logging, which in turn protects many other species
The graph of SPECIES EXTINCTION follows the graph of _____________________, which suggests that a high proportion of animal extinction is human caused
A good animal used to test pollution in air is the ____________.
- (Aphibians respirate through their skin)
Benefits of saving biodiversity:
- Pharmaceuticals (diversity of plants provide tx)
- Ecosystem Services (free like air & water)
- Biophilia (innate love for nature as part of culture)
Specific Examples of Ecosystem Services
- Purification of air & water
- Detox & composition of wastes
- Cycling of nutrients
- Moderation of weather extremes
- Written by E.O.Wilson
- Innate love for biology
- Loss will be like losing cultural diversity
- Will hopefully motivate realignment of environmental priorities
How did Easter Island's population decline?
Once full of trees, but they were cut down & used to move large statues (suspected) Without trees, unable to make canoes & fish. Population in great decline.
Same thing we are doing when using precious rare earth metals in our electronics
3 Major Threats to Biodiversity:
- 1. Habitat destruction
- 2. Introduced species
- 3. Overexploitation
The greatest threat to biodiversity is ____________________.
Habitat Loss from human alteration
- GREATEST THREAT TO BIODIVERSITY
- Fragmentation & destruction lead to loss
- ex. in Wisconsin, praries occupy only 0.1% of its original area
- ex. ~93% of coral reefs damaged by human activities
What is wrong with small populations?
- Loss of Genetic Variation
- Population split into 2 segments
- ex. by a highway or large road where animals will die if they try to cross.
Positive feedback loop that reduces population size. KEY FACTOR IS LOSS OF GENETIC VARIATION allowing evolutionary responses to environment change. SMALLER IT GETS, THE LARGER THE VORTEX
- + Genetic drift
- + Inbreeding
- + Recessive alleles as homozygotes
- + Chance for diseases
- - Genetic variability
- - Ability to adapt
- - Fitness
- - Reproduction
- - Survival
- - Population
Are those that humans move from the species' native locations to new geographical locations
- Rapid population growth
- Rapid expansion in range
- Great costs to environment
- "RULE of 10" = 10% that move survive, 10% of those INVASIVE, Very successful (1%) but at great cost
ex. Argentine ant, yellow mustard
- Once most abundant NA bird
- - 5 billion
- - Single flock=2 BILLION span 1x300 MILES
- Hunted for meat for poor & slaves
- Last one Martha died in 1914
- Used booze soaked grain & one tied to stool with eyes sewn shut to attract large flock (they were very social)
Human harvesting of wild plants or animals at rates exceeding ability of population species to rebound
Marine Fisheries & overexploitation:
- 2004: 104 million metric tons of food
- China 47.5 million metric tons
- Top caught species= anchovies off Peru (10.7 million metric tons)
Why are fisheries so destructive?
- 1. Hard to measure
- 2. Regulation hard b/c in international waters
- 3. Hard to police
Biodiversity Hot Spots
- Relatively SMALL area
- w/ LARGE amount of ENDEMIC species, & LARGE # of endangered or threatened species
- ex. SoCal
Why is CA a hotspot & why is it threatened?
- Lots of endemic species:
- Due to unusual mediterranian climate, isolation due to mountains & desert to east
- "An Island called California"
- Lots of development:
- Great climate attracts lots of people
- Chaparral easy to develop
- Conserve animals OUTSIDE natural environment. Able to:
but..they're not in natural habitats
- Protecting the Land & Species
- Realistically can't just block off big pieces of land
Costa Rica: Protected land in buffered areas: Have SOME regulations, can have VILLAGES, just not large-scale INDUSTRY
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