Bio 401 midterm 1
Terms in this set (90)
current size and growth rate.
7.3 billion. GR 1.2%
3 most populous nations in world.
china, india, USA
Where the majority of global population growth is occurring.
developing nations, tropics and sub tropics
Estimated global population by 2050.
human impact depends on what 2 factors?
total population X per capita resource use
countries rescaled on map to reflect population size, not geographic size
how large is a hectre (ha)?
100 m X 100 m. 10,000m^2. 100 ha in 1 km^2
Consumption: "ecological footprint" US average vs world average.
9.6 hectares v 2.2 hectares
If everyone in the world had our standard of living (= per capita rate of resource consumption), then how many planets would we need to provide all these resources?
definition of "biodiversity" - how is it different from "wildlife"?
The variation of life at all scales.
The variety and variability of life.
consumptive use vs non-consumptive use [Note: this idea of "consumptive use" is different than the textbook's "consumptive value"]
Consumptive benefits-Food, medicine, other products. kill/ consume organism
Non-consumptive benefits-Recreational, spiritual, symbolic. doesn't consume organism
what are instrumental values?
consumptive benefits, non-consumptive benefits, service and potential
Understand the concept of "ecosystem services" and several examples
Service benefits-Pollination, pest control, erosion control, etc.
what is a potential value?
Future development of medicine, technology, etc.
what is intrinsic value?
value all organisms have irrespective to how they do or could potentially benefit humans
What is the practical difference between "willingness to pay" and "compensation" approaches to estimate the value of biodiversity?
"Willingness to pay" (WTP) approach: How much would you be willing to pay to save Giant Pandas?
"Compensation" approach: If Giant Pandas went extinct, how much should you be
Philosophical positions of Gifford Pinchot, John Muir, Aldo Leopold, Michael Soulé
Pincho- "resource conservation ethic"- sustainable use of resources (utilitarian, conservation)
Muir- "romantic preservation ethic"- Preservation non consumptive (scenic,spiritual)
Leopold- "The Land Ethic" - Stewardship of ecological community
Know the primary traditions of conservation in N. America, and the relationship of Conservation Biology to these traditions.??
typically we wanted to conquer our environment. need now to conserve it.
Understand the distinction between "conservation" and "preservation"
Put simply conservation seeks the proper use of nature, while preservation seeks protection of nature from use.
Is conservation biology an "applied" or "basic" science - why?
applied- uses many different basic sciences to answer its questons
Michael Soule's four postulates (and corollaries):
a. The diversity of organisms is good. (Untimely extinction is bad.)
b. Ecological complexity is good. (Simplification of ecosystems is bad.)
c. Evolution is good. (Interference with evolution is bad.)
d. Biological diversity has intrinsic value, irrespective of
human use or benefit.
currencies: richness, evenness, endemism, overlap
richness- how many species occur in the habitat
evenness- weighted. simspons d- most even highest number to that amount of species.
endemism- occurs only in that habitat
overlap- how many species in one habitat occur in another
how do you calculate evenness?
D= 1 / Σpi^2
pi= proportion of each species i
weight factors: native vs non-native, rare vs common, etc.
native are more weighted; rare are more weighted
spatial scale: alpha, beta and gamma diversity
alpha- richness in a habitat
beta- richness (turnover) between habitats (high when sites have different species)
gamma- diversity of entire region- beta and alpha diversities. (high when alpha and beta are high)
Do conservation biologists tend to use richness or evenness more? Why?
evenness, site can have 10 animals but only 2 species. there could be 9 of 1 species and 1 of the other if used for richness.
How many species have been described by science? Which taxa are notably speciose?
1.9 million described by science. 50% are
How many species probably exist?
Be familiar with several methods used to estimate global species diversity
Irwin's "bug bomb" and the logic behind his species estimate
species accumulation curve- Using the rate of documented species to estimate how many species are present but not detected.
killed bugs and took that number on tree and percentages to calculate amount of beetles.
4 main terrestrial biogeographic patterns of richness and endemism
1. Latitude-Species richness increases as latitude decreases (toward tropics)
2. Area Larger areas have more species
3. Structural complexity Species richness increases with structural complexity of the environment
4. Isolation Isolated areas have lower richness but higher endemism (fewer species, but more uniqueness)
As latitude decreases, the geographic ranges of individual species shrink steadily.
Species at higher latitudes tend to extend across greater geographic area. Species near the tropics tend to be more highly localized.
Tropical biodiversity is highly diverse, and also highly
localized. tropical areas have high alpha, beta,
and gamma diversity.
Species-Area Curve and its implications
The number of species in an area is proportional to the size of the area, but the relationship is NOT linear.
a 10X increase in area causes a ___X increase in species
Endemism: Definition and implications
species that only occurs in one area. higher need for conservation, easier to go extinct. uniqueness. usually island species
Which US state has the most native species? the fewest native species? the most endemic species? the highest proportion of endemic species?
california has the most, hawaii the least. hawaii the most endemic proportionally. cali most numerically
"diversity hot spot" concept
"Hot Spots" of richness, endemism & threat
More than 60% of the world's terrestrial biodiversity is found in just 1.4% of the land area.
How many global hotspots of biodiversity? How many in tropics? How many occur, at least to some extent, in the US? What is the key non-tropical biome (major ecosystem type)? (See Myers paper for this detail)
25, most in the tropics 16, 3 in america, mediterrean
why do the tropics have so many species?
Hypothesis 1: higher speciation rates
Hypothesis 2: lower extinction rates
Why is Madagascar such a high global priority for conservation?
alot of endenism in a small area
California's importance as national and global biodiversity hotspot
At least 4,425 vascular plant species (48% endemic)
• This area has more plant species than central and northeast USA and adjacent portions of Canada - an area 10 times larger.
Vertebrate diversity: (12% endemic)
contains most of the US rarity and richness
California Floristic Province - how does it relate to state boundary?
goes along sierras into oregon coast and baja coast
Know the 3 fundamental patterns that affect population dynamics: the growth pattern (in the absence of limits), the upper limit, and the lower limit
a. Exponential growth (r)
b. Carrying capacity (K)
c. Negative density dependence (Allee threshold)
K as a negative feedback process
carrying capacity, grows until this rate then remains the same. increase(pop) leads to a decrease(POP)
Allee effect as a positive feedback process (critical minimum threshold)
hits this level then circles downhill. gets worse and worse.
What is an Allee effect? Know some biological examples of this phenomenon.
Small populations have lower fitness
Populations that fall below a certain "critical minimum" will have diminished survival and reproduction.
penguins, oxen, auk
4 factors that cause allee effect
1. reduced success in fertilization
2. critical group behaviors become impossible
3. inadequate social cues for key behaviors
4. vulnerable to inbreeding/ genetic drift/ random facors
4 main threats to biodiversity (e.g., the "Evil Quartet)
habitat loss, exotic/ nonnative species, over exploitation, ecological linkages/cascade effects
5 key intrinsic characteristics that make a species vulnerable to these threats. (know 1-2 examples of each)
A. Species that are a resource for humans, or compete
with humans for a shared resource (fisheries)
B. Specialists (panda)
C. K-selected ("slow" life history strategy) rhino
D. Endemic to islands- dodo bird
E. Small and / or highly localized population (Devils fish)
Demographic phases of extinction: (declining, bottleneck, extinction, recovery)
pop shrinking, drastically shrinks and recovers, gone, coming back
What are "deterministic" vs "stochastic" processes? Know examples of each.
deterministic- deterministic factors: overhunting and habitat destruction. known.
What are the main "stochastic effects" that affect small populations?
a. Are "close to the brink" of extinction - cannot withstand much impact
b. Are vulnerable to many stochastic (random) factors:
Genetic: Inbreeding and genetic drift can reduce individual fitness, population persistence, and evolutionary potential.
Environmental: Fire, flood, volcano; other environmental changes.
Demographic: Random events in the sex and age structure of the population. Of final 13 Heath Hens, 11 were males. Of final 6 Dusky Seaside Sparrows, all were males.
Random effects become very important in very small populations.
global loss of a species; zero left.
extinct in wild
extinct in wild but not captivity
still alive but no longer producing its ecological effects
"living dead" species
individuals still alive but no possible way to reproduce/ can't reproduce fast enough to repopulate. american chestnut
average "lifespan" of a species, inferred from the fossil record
1-5 million years. wilson assumption of 1-10
Key lessons on extinction learned from the fossil record
species increase throughout time gradually, with 5 major extinctions in history. 6th is happening currently
How many "mass extinctions" in fossil record, since rise of multicellular life
Which extinction was the most extensive; "The Great Dying"
Permian extinction, the great dying. 251 mya. 77-96% species went extinct world wide
"K-T extinction": Date; likely cause; significance for modern biota
death from meteor. 65 mya. dinosaurs gone and rise of the mammals begins
species concepts (3)
1. biological- spp can mate and produce viable offspring
2. morphological- if 2 individuals look the same, they are the same spp
3. phylogenic- if 2 individuals' DNA is the same then they are in the same spp
how long does it take a spp to recover from near extinction?
20-100 million years
what is the background rate of extinction?
"natural" extinction rate that's always occuring. 10 spp/ yr
what is the modern extinction rate?
2-3 spp/ year (does not include current background extinction rate, silent extinctions, missing species, living dead species)
Be able to explain how conservation biologist E.O. Wilson estimated the current extinction rate (using the Species Area curve, the rate of tropical deforestation, and the estimated number of species in the tropics). Know the values he used and be able to re-construct his deduction and conclusion. What is the resulting annual extinction rate? How does this "estimated rate" compare with the recent observed rate, the fossil "background" rate, and the fossil mass extinction rates of extinction?
used tropical forests to estimate extinction with deforestation rates and a species area curve.Estimating Current Extinction Rate using Species Area Relationship
"background rate" = 10 spp / yr
"mass extinction rate" = 1,400 - 3,500 spp / yr
this estimates 27,000 loss annually= 74 spp/ day = 3 spp/ hour
Documented modern extinction rate: 800-1100 spp since 1600 AD( = 2-3 species annually).
What is the "Pleistocene Overkill Hypothesis"? What kinds of species did it apply to? What continent's pattern suggests the role of humans?
The overkill hypothesis argues that humans were responsible for the Late Pleistocene extinction of megafauna in northern Eurasia and North and South America & Australia
Why is it hard to quantify the "current" rate of extinction (over the last 400 yrs)? (2 main reasons)
a lot of species haven't been discovered. lazarus species and centinelan species.
When and where was the Polynesian Expansion? What kinds of species were primarily affected?
3000-300 years ago to polynesian islands. endemic bird species.
"Lazarus species" - concept and at least 2 examples
thought it was extinct, but its not. stick bug, guadalupe seal, blonde capuchin monkey
"Centinelan extinction", and the case study of Centinela
silent extinction. goes unnoticed. Guadeloupe seal? Lobe-finned fish are likely ancestors of modern tetrapods (reptiles, amphibians, birds and mammals). Thought extinct for >60 My, until 1938 when a single specimen was caught in deep water off the eastern coast of South Africa. A second specimen was caught in 1952; a second species was discovered in an Indonesian fish market in 1997.
What are the main criticisms of Wilson's estimation approach? Does it over-estimate or under?
probably overestimates since the tropics contain the most amount of species. and because it doesnt account for species being able to come back if land is reestablished or species that can fly away, birds.
What is "the Sixth Extinction"?
the extinction we are currently causing.
basic demographic models: Exponential vs Logistic growth
exp- pop doubles every generation
logistic- sigmoidal growth, hits carrying capacity and plateaus
λ: conceptual and mathematical definitions
growth rate. 2 is doubled, 1 is replacing, 0 is not growing, negative is declining
Why are deterministic models not particularly useful for calculating extinction probabilities or time to extinction for critically endangered species?
doesn't account for stochastic factors
PVA - what is it? How does a PVA differ from the deterministic models above? How is stochasticity incorporated? Why are multiple runs necessary? Be able to explain why PVA is a kind of risk analysis.
PVA is simply a demographic model that incorporates stochasticity. Rather than being identical every time step, some vital rate is randomly selected from a distribution. Example: λ (Normal; mean of 2, SD of 0.5)
Due to the randomness, each simulated population will have a different trajectory
quasi-extinction: what is it and why is it important?
population falls to a number where they are pretty much extinct.
Minimum Viable Population
The smallest population with a specified probability of remaining extant for a specified period of time.
Key shortcomings / abuses of PVA (see slide for details)
1. PVAs can require lots of data.
May not have all this data for many endangered species. It is better to have simpler models with good, local data, instead of a fancy, complicated model with extrapolated data.
2. Model assumptions may change over lengthy time periods.
3. Managing for the MVP: Risky! What if you're wrong??
4. Models are not reality.
Remember: Reality is a sample size of 1.
"Statistically unlikely" does NOT mean "it won't happen"
D = 1 / Σpi2
simpsons d, represents dominance
- Kirtland's Warbler
jack pine is needed. almost went to extinction, habitat loss?
Loss of 50% of habitat = loss of 10% of species
Loss of 90% of habitat = loss of 50% of species
- American Chestnut
living dead species. affected by chestnut blight.
- Passenger Pigeon
bird was so abundant and hunted to extinction.
- Heath Hen
The heath hen was brought to the brink of extinction by
deterministic factors: overhunting and habitat destruction.
Once the population became very small, it was vulnerable to stochastic factors, which eventually caused its extinction.
- Devil's Hole Pupfish
water level was lowering. smallest highly localized population. susceptible to stochastic factors.
- Dusky Seaside Sparrow
stochastic demographic factored extinction. 6 left all male
- Lord Howe Island Stick Insect ("land lobster")
lazareth species that was thought extinct then found on ball island. brought into captivity
Guadalupe Island Fur Seal
Didnt know it was a species. could of been a silent extinction. almost hunted to extinction. thought to be extinct.
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