Exam 1 Flashcards
Three types of Biodiversity
Ecosystem, species, and genetic diversity
Speciation
the process by which one spp splits into two or more
Biological species concept: species def
a group of populations whose members have the potential to interbreed in nature and produce fertile offspring.
Reproductive isolation
prevents members of different spp from mating with each other; prevents gene flow between spp: therefore the spp are distinct from each other
Conservation Biology
mission-oriented, crisis-driven, problem-solving field focused on the preservation of biological diversity
Extirpation
the loss of a single population of a species
Extinction
irreversible loss of all populations of a species
Hybrids
When some pairs of clearly distinct species occasionally interbreed and produce hybrids (ex: Grizzly and Polar Bear)
Morphological Species Concept
classifies organisms based on observable physical traits (applied to asexual organisms and fossils)
Homology
the similarity in characteristics that result from common ancestry
Homologous structures
have different functions but are structurally similar because of common ancestry
Vestigial structures
remnants of features that served important functions in an organism’s ancestors
Nonhomologous/analagous traits
Similarities resulting from convergent evolution (similar habitats, diets, etc)
Ecological Species Concept
defines a spp by its ecological role or niche and focuses on unique adaptations to those roles in a biological community (ex: 2 spp may look similar but differ in diet or habitat)
Phylogenetic Species Concept
(most modernly used) defines a spp as the smallest group of individuals that shares a common ancestor (done by testing DNA or morphology)
-difficulty in determining amt difference necessary to separate spp
3 Key Points about Evolution by natural selection
1) Individuals do not evolve: populations evolve
2) natural selection can amplify or diminish only heritable traits, not acquired ones
3) evolution is not goal directed and does not lead to perfection (favorable traits vary as envr changes)
3 Modes of natural selection
- directional (causes characteristics to take one extreme more)
- stabilizing (keeps characteristics more moderate-extremes die)
- disruptive (some factor causes all moderates to die, almost creating two spp of remaining extremes, but factor leaves and spp come back together)
Mutation definition
changes in the nucleotide sequence of DNA and the ultimate source of new alleles
Prezygotic Barriers
(physical barriers before zygote formation) Habitat (Garter snakes), temporal (E&W Spotted Skunks), behavioral (birds), mechanical (flies), and gametic isolation (corals&anemones)
Postzygotic Barriers
(genetic/embryonic barriers after zygote formation) Reduced hybrid viability, reduced hybrid fertility, hybrid breakdown
Allopatric Speciation
when landmasses separate organisms and prevent them from mating (ex: Antelope Squirrels)
Polyploidy
cells have more than two complete sets of chromosomes
Sympatric Speciation
can result from polyploidy by self-fertilization or by hybridization (80% of all living plant spp)
Adaptive radiation
the evolution of many diverse spp from a common ancestor (ex: the Galapagos Archipelago-finches)
Supporting services (MA: eco services)
nutrient cycles and pollination
Provisioning Services (MA: eco services)
providing food and clean water
Regulating Services (MA: eco services)
control of climate, pests and disease
Cultural Services (MA: eco services)
spiritual and recreational benefits
Millennium Ecosystem Assessment
(MA) produced by the federal govt in 2001. Popularized the term “ecosystem services”
Mobile Links
spp that provide critical ecosystem services and increase resilience by connecting habitats and ecosystems as they move between them
Role of biodiversity toward public health?
many vector-borne diseases are related to diversity decline, resulting in higher outbreaks (Monkey Pox, Malaria, HIV, Ebola…)
Arthropod-borne disease cycle
many arthropods of concern such as mosquitoes and ticks carry diseases since they feed off of more than one host (reservoir hosts) in the form of small mammals, etc. They then go on to larger hosts like humans and spread the pathogen/virus
Vector presence vs vector competence
in terms of vectors like ticks, only some of their reservoir hosts have high competence to transmit the disease. Therefore, higher pops of these spp and/or less diversity overall will result in greater disease outbreaks
factors affecting disease transmission
distribution of vector, host selection, reservoir competency as disease hosts, vector competency and disease transmission
Transmission
the ability of a pathogen to be transmitted from mother to egg and different life stages
3 mechanisms to conserve biodiversity in traditional practices (Box 1.1)
- Land use regimes that maintain forest patches at different successional stages
- creating patches, gaps, and mosaics to enhance diversity in a given area
- boundaries between ecological zones, creating new edges for edge-loving spp
The Evolution of the Conservation Biology discipline (6 sections)
- implementation and transformation (innovative techniques and tech; transforming to role of science in cons)
- adoption and integration (‘permeation’ of con bio in other fields and others in it)
- marine and freshwater conservation
- building capacity (growing the methods and acknowledgement of the field’s core values)
- internationalization
- seeking a policy voice (whether to lobby or not)
Why might there be more diversity of higher level taxa in the oceans than on land?
we have much left to discover in the oceans. What we know most about are larger animals and those with steady fossil records (higher level taxa)
Since life likely began in the seas, this would also support the reason for higher level taxa
Why more diversity in freshwater systems?
many freshwater systems (wetlands) can be very unique environments that call for specific characteristics
Why are the neotropics the most diverse of terrestrial ecosystems?
most diverse for species of amphibians, reptiles, birds, and mammals
this reflects the variation in the histories of the realm and the interaction with emergence and spread of these groups
Where is the peak in diversity in latitude?
20-30 degrees North
Global Carbon Cycle: 4 main reservoirs
- CO2 in atmosphere (plants)
- organic C compounds within organisms
- dissolved C in water bodies
- carbn compounds death inside earth and buried OM ex: coal
Greenhouse Effect
gases like CO2, methane, and nitrous oxide trap the sun’s heat: warming the planet
examples of how humans affect P and N cycles
burning coal: nitrogen in form of N2O;
fertilizer runoff causes sedimentation/eutrophication of waterways (P AND N)
6 major eco services of soils
- moderate the hydrologic cycle
- physical support of plants
- retention and delivery of nutrients to plants
- disposal of wastes and dead OM
- renewal of soil fertility
- regulation of major element cycles
importance of forest ecosystems in mediating the hydrologic cycle
reduce flooding (interception and retaining); buffers against weather and regional climate change
3 categories of Mobile Links
- genetic (pollinators and seed dispersers carry genetic material from plant to plant)
- process (grazers that influence pops of plants, invertebrate, and vertebrate prey)
- resource (like bears leaving salmon carcasses in woods-moving nutrients from place to place)
Consequences of pollinator decline
more than 1200 vertebrate and abt 289,000 invertebrate spp pollinate over 90% of flowering plant spp
Especially for plant/species relationships that have had coevolution, if insect dies, so does plant, increasing diversity loss
How are extinction rates calculated?
(# extinct/(ttl # group*100))
unit of species extinctions:
extinctions/species/million years: E/MSY
average background rate of extinctions
1 E/MSY
How many birds at risk of extinction according to Birdlife International?
1210 bird spp; 182 would be extinct now if not for conservation
all 1210 expected to go extinct in next few decades w/o conservation
local rarity
depends on range size. spp with large ranges are more common and vice versa
7 laws of biodiversity
1) Every spp has come into existent coincident both in space and time with a pre-existing closely allied spp
2) Most spp’ ranges are very small; few are large
3) Species with small ranges are locally scarce
4) # spp found in an area of given size varies greatly according
to some common factors
5) Spp with small ranges are often geographically concentrated…
6) those conc are usually not where the greatest # of spp are found, but often in same areas where other taxa of diff origins are found
7) The fraction of species remaining when human actions reduce the area of original habitat
Important Consequences
Locally rare spp are most at risk of extinction (there can therefore be more focused conservation efforts bc small range)
Any conservation priorities in Europe or NA are likely to be poor choices to prevent extinctions bc they have few spp overall and few spp with small ranges (thus more extensive cons efforts needed)
Myers’ Hotspots
takes ‘top-down’ approach to study biodiversity
the criteria are that hotspots have more than 1000 endemic plants and have less than 30% of their natural vegetation left.
Microevolution
Change in the gene pool of a population from one generation to another
Why are terrestrial and freshwater systems more diverse?
The fragmentation of landmasses etc due to tectonic plate movement, glaciation, etc
How many spp have scientists formally named and described?
Abt 1.8 million
Major anthropogenic threats to biodiversity
Agriculture, urban development, forestry, mining, and environmental pollution
Phenotypic plasticity
Ability of organisms and/or populations to adapt to changing environmental conditions (ex: birds nesting earlier)
