Part I Flashcards
conservationist
someone who advocates or practises the sensible and careful use of resources
preservationist
someone who advocates allowing some places/creatures to exist w/ significant human interference
environmentalist
someone who is concerned about impact of people on environment quality
ecologist
scientist who studies the relationship b/w organisms and enviro (often analogous in media to environmentalist)
history of
- preservation
- environmentalism
- ecology
- establishment of Yellowstone national park marks beginning of gov. policy of preservation
- ‘Silent Spring’ by Rachel Carson in 1962: treatise on pesticides
- global environmental movement in UN 1972
- not in public eye until advent of environmentalism
- new gov. agencies, advocate groups, etc. that needed ecologists
Callicott ethics
- Romantic Transcendental Preservation ethic
- Resource conservation ethic
- Evolutionary-ecological land ethic
romantic-transcendental ethic
- John Muir C19th
- communication w/ nature brings people closer to god
- visiting ancient forests for this purpose morally superior to using for agro
- i.e. nature is a temple sullied by people
resource conservation ethic
- Gifford Pinchot C19th
- nature consists solely of natural resources and should be used to provide the greatest good for greatest #people for longest time
- not a call to plunder land but to distribute benefits efficiently and fairly
- emphasized not short changing future
- can recognise aesthetics as a resource
- natural resources should be owned/regulated by gov.
evolutionary-ecological land ethic
- Aldo Leopold C20th
- people are citizens of biotic system, not separate
- people have righ tot use/manage nature but responsible for recognising value of other species
- could use destructive tools to mend environment
conservation biology
applied science of maintaining Earth’s biology
biodiversity
variety of life in all forms and at all levels of organization
genes
self-replicating pieces of DNA that shape form+function of each individual organism
ecosystem
gorup of interacting organisms and physical environment they inhabit at a given time
species
groups of actually/potentially interbreeding natural populations which are reproductively isolated from other such groups
Why is diversity of ecological functions so enormous?
- millions of species interacting w/ each other
- every species interacts w/ own environment
functional biodiversity
variation in processes carried out in diff. levels of biodiversity
structural biodiversity
variation in way parts are organised (e.g. population structure)
why do biologists usually focus on maintaining structural biodiversity rather than functional?
- more straightforward (easier to inventory species than interactions)
- if maintain SD, FD maintained as well
how to measure biodiversity?
- determine which elements of biodiversity are present (richness)
- determine relative abundance of diff. species (evenness)
extinction
disappearance of a species from earth (or smaller area - extirpations)
endemic
species only found in a defined geographic area
- alpha
- beta
- gamma
diversity
- diversity w/in ecosystem
- diversity among ecosystem
- geographic-scale diversity
maximise biodiversity
- implies manipulation
- e.g. increasing alpha diversity of ecosystem
maintain biodiversity
keep all elements of biodiversity despite human activity
enhance/restoring biodiversity
may be short-sighted, unless means restoring ecosystem to previous state
protecting biodiversity
similar to maintaining but w/ emphasis on -ve human impact
preserving biodiversity
similar to protect and implies only way to maintain biodiversity is to isolate from humans
conserve biodiversity
use it carefully and not diminish LR
biotic integrity
- wholeness of a biological system
- includes presence of all elements at appropriate densities and occurence of all processes at appropriate rates
sustainability
ability to maintain something over time w/out diminishing it
why is it difficult to define a species?
lack of clear classification
evolutionary significant unit (ESU)
population that has been reproductively isolated long enough to have evolved significant genetic/ecological divergence from other groups of same species
management units (MU)
local populations that, b/c so little dispersal among them, have evolved genetic differences
distinct population segment (DPS)
takes into accounts ESU/MU but also involves political boundaries
how many species?
- 3.6-117 million (13.6 is reasonable working figure)
- scientists know 1.7 million
value of species to conservationists
- independent of value to humans or even to own ecosystem
- each species has intrinsic value
- therefore, species threated w/ extinction prioritised
IUCN Red List
primary international standard for conservation of various species
rarity
- geographic range
- only found in small area (local endemics)
- habitat specificity
- only occur in specific, uncommon habitats
- local population size
- occur at low pop. densities where they are found
extinct categories in IUCN Red List
- extinct
- no reasonable doubt a species had died (e.g. great auk)
- extinct in the wild
- known only to survive in cultivation/captivity/naturalised pop. outside past range (e.g. Guam rail)
threatened categories in IUCN Red List
- threatened: critically endangered
- meets any A-E criteria + therefore faces extremely high risk of extinction in the wild (e.g. black rhino)
- threatened: endangered
- ” “ very high “ “ (e.g. giant pandas)
- threatened: vulnerable
- ” “ high “ “ (e.g. cheetah)
- near threatened
- close to qualifying for threatened category in future (e.g. jaguars)
other categories in IUCN Red List
- least concern
- widespread and abundant
- data deficient
- inadquate data to assess risk of extinction (e.g. many fish)
- not evaluated
- not yet assessed - most species fall into this category (e.g. all invertebrates)
quantitative criteria for assessing threatened status
- A: reduction in pop size
- B: geographic range
- C: absolute pop. size <250 and declining pop. projections
- D: “ “ “ <50
- E: probability of extinction >=50%
economic value of species
- food
- medicine
- clothing/shelter/ tools/ trinkets
- fuel
- recreation
- services
issue of wild species as food
- most domesticated species are closely realted to species that are wild and wild species source of genetic material
- wild species may be source of new domesticates
- wild species still major food source for people
dominant species
species constitutes a large portion of biomass of ecosystem
controller species
major roles in controlling movement of energy/nutrients
keystone species
species that play critical ecological roles that are of greater importance than we would predict form abundance
ecological extinction
species becomes too rare to fulfill its role in an ecosystem
umbrella species
- species w/ large home ranges and broad habitat requirements
- sprotecting habitat for their populations protects habitat for many other species across broad set of ecosystems
- e.g. tiger
indicator species
- health of these populations is an easy way to monitor environmental conditions/status of other species
- smaller species more sensitive e.g. lichens
why is distinguishing b/w ecosystems difficult?
- web of interactiosn doesn’t have clean breaks
- ecosystems thought about at variety of spatial scales (e.g. earth can be considered an ecosystem)
reasons for ecosystem classifications
- efficient communication
- data reduction and synthesis
- interpretation
- land management and planning
why do ecosystem classifications emphasize vegetation?
- vegetation is major component of terrestrial communities
- integrating measure of site factors
- relatively accessible features
value of ecosystem
- summation of value of constituent organisms
- also economic and spiritual value to humans
mechanisms for higher diversity increasing stablity
- if more species in ecosystem, food web more complex, w/ greater redundancy among species in terms of ecological niche
- diverse ecosystems less likely to be invaded by new species that would disrupt ecosystem
- in species-rich ecosystems diseases spread more slowly b/c each species relatively less abundant –> average distance b/w species increases
why are we interested in landscape phenomena?
- many endangered species are large animals w/ large homes that encompass many ecosystems - must sustain entire landscapes to suit needs
- human activities have left many natural ecosystems isolated in matrix of human-altered ecosystems
genetic diversity @ 5 levels of organisation
- higher taxonomic categories e.g. phyla and families
- among species
- among pop.
- w/in pop.
- w/in individuals
protein electrophesis
- tissues collected from many individuals
- macerated
- separated by electrophoresis
- stained for enzymatic/protein activity
- patterns compared + gels scored for bands
restriction fragment length polymorphism (RFLP)
- high molecular weight DNA cut w/ site specific restriction enzyme
- electrophoresed and stained for nucleic acids
- determine lengths of fragments by distringuishing fragments which have gained/lost sites
- closely related taxonomies have particular sized fragments
random amplification of polymorphic DNA (RAPD)
- purify DNA
- isolate random fragments using polymerase chain reaction
- electrophorese, then stain + diagnose
- ADV: allows for analysis of tiny samples
simple sequence repeat (SSR) polymorphism (microsatellites)
- visualise bonding patterns at specific locus
- diff. banding results from diff. #repeating nucleotides
amplified fragment length polymorphism (AFLP)
- uses selective PCR amplification of restriction fragments
- if mutations occurs, will not show up mutant on electrophoresed - called dominant markers
DNA sequencing
- specific genes isolated using PCR
- fragments diff. size sorted in electrophoretic gel
polymorphism
proportion of genes that are polymorphic (frequency of most common allele less than arbitrary threshold)
rare alleles
- frequency less than .005, .01 (depends)
- have to fitness advantages for individuals
heterozygosity
proportion of genes at which average individual is heterozygous
why is genetic diversity important?
- evolutionary potential
- some individuals must be fitter than others
- if everyone genetically identical no change
- loss of fitness
- inbreeding depression: creates small, weak individuals if breed w/ close relatives
- homozygosity –> expression of recessive deleterious alleles usually suppressed
- pop. will die in event of disease, natural disaster, etc.
- utilitarian values
- diversity allows people to decide what they want to breed for
- allows us to grow same species in diff. enviro
- source of genetic material that may be useful
founder event
few individuals arrive in new area and establish new pop. that is inevitably small to start
genetic bottleneck
- when pop. collapses, genetic diversity of original pop. decreases b/c only sample of original gene pool retained
- causes loss of (rare) alleles and redution in variety of genetically determined characteristics
random genetic drift
random change in gene frequrencies that is likely to occur in small pops. b/c each generation only retains portion of gene pool sample may not be representative
effective pop. size
individuals in a theoretically ideal population that would have same magnitude of random genetic drift as actual pop.
cultural transmission
information moves among individuals and generations through learning
