BIS2B Lectures/Discussions Flashcards
Ecology
scientific study a b/n organisms within themselves + their envnmnt.
Abiotic
non-living factors affecting environment
Biotic
living factors that affect environmental factors
Individual
individual traits determine response to environmental factors
Population
interacting group of cospecific individuals
Species
group of organisms w same type, common ancestor, defined by ability of grp. members to interbreed w only one another
Community
set of co-occuring, interacting species
Ecosystem
interacting systems of species and their abiotic environment
Evolution
change in a genetic composition of a population over time
Natural selection
diff. survival and/or reproduction of individuals w/ diff. trait values within pop.
Adaptive evolution
process of evolution through natural selection
Adaptive trait
trait that has evolved to enhance organism’s survival/reproduction in its environment
Rapid evolution
evolutionary and ecological processes may occur on similar time scales leading to feedbacks that can be observed directly
Habitat/Ecosystem
grouping of organisms and their physical environment
Higher taxa
grouping of species based on genetic/ecological similarity
Genetic
heritable differences among individuals of same species
Plasticity
variation among individuals w/ same genes
Transect sampling
sampling in which a biologist runs a line (transect) through a habitat and records every organism on either side of the line
Quadrat sampling
sampling in which a biologist divides a habitat into rectangles(quadrat) and records organisms found in random areas of the quadrat
Species richness
of species
Relative abundance
of species that are present
Species evenness
diversity index/how close in numbers each species are in an environment
Endemic
only occurring in one area
Climate
measure of the avg. pattern of variation in temperature, precipitation, and other meteorological variables in a given region over long periods of time
Biomes
the world’s major communities, classified according to the predominant vegetation and characterized by adaptations of organisms to that particular climate
Chapparal
example of a biome; temperate shrubland and woodland; hot, dry summers; cool, moist winters; dense vegetation, vulnerable to summer fires (eg. California)
Determinants of climate
incident solar radiation; air circulation driven by + solar radiation and earth’s rotation
Coriolis effect
result of the Earth’s rotation on weather patterns and ocean currents; makes storms swirl clockwise in the Southern Hemisphere and counterclockwise in the Northern Hemisphere
Trade off
relationship b/n the benefits of a trait in one context and its costs in another context
Principle of allocation
all life functions cannot be simultaneously maximized
Autotrophs
can live exclusively on inorganic sources of carbon nitrogen, and other essential resources
Photoautotrophs
use energy from sunlight to power metabolism, growth and resource-gathering
Heterotrophs
use pre-formed organic molecules as food(source of carbon, nitrogen, energy, and other essential resources)
Net photosynthesis
photosynthesis-respiration
Gross photosynthesis
(change of oxygen in light) - (change of oxygen in dark)
Gross primary productivity
total carbon fixed by plants per unit time
Net primary productivity
gross primary productivity - respiration
Root to shoot ratio
more nutrients, less sunlight(less root, more shoot) & vice versa; ratio of below ground to above ground biomass
Liebig’s law of minimum
production only occurs @ a ratio permitted by the most limiting factor
Herbivores
consume plants, dentition for grinding plans, long gut to aid digestion of low quality plants, piercing/sucking mouth parts in come insects, enzymes to detoxify chem. defenses
Carnivores
attack & consume animal material, adaptations to subdue/pursue prey, stinging cells/sharp teeth
Omnivores
consume both plant and animal matter, generalist morphologies, may be indiscriminate feeders
Dentritivores
consume dead plants or animals,
Adaptation
evolutionary change in genotype that increases performance
Acclimation
change in phenotype within an individual’s lifetime to increase performance (often reversible)
Fundamental niche
set of environmental conditions (e.g., temp., moisture, salinity) under which individuals of a species can grow and reproduce
Isometric scaling
all dimensions increase the same amount as the size the organism changes
Allometric scaling
disproportionate growth of a part or parts of an organism
Metabolic rate
amount of energy expended daily at rest
Density
number of individuals/area of a quadrat
Closed population
immigration and emigration negligible; changes dominated by births and deaths
Open population
immigration and emigration substantial
Intrinsic rate of growth
rate of population if there is no density dependent forces acting upon the population
Carrying capacity
number of organisms that a region can support w/out environmental degradation
Survivorship (lx)
proportion of individuals surviving to age x
Direct method (counting survivorship)
following a cohort through time
Indirect method (counting survivorship)
determine age of death from remains
Type I (survivorship)
low mortality until the latter stages of life (seen in humans, but not always)
Type II (survivorship)
probability change of surviving to the next yr. is independent of age (seen in mammals, birds)
Type III (survivorship)
high juvenile mortality but low adult mortality
seen in trees, large reptiles
Fecundity (mx)
average number of offspring produced by individual age x
Positive interactions
interactions among two organisms that benefit at least one organism and does not harm the other; NO ALTRUISTS
Commensalism/Facilitation
interaction in which one organism benefits while one is unharmed (+, 0)
Mutualism
both organisms benefit (+,+)
Four forms of stress that positive interactions can ameliorate
- Physical stress (shading/sheltering)
- Nutritional stress
- Reproductive limitations (dispersal, fertilization)
- Refuge for natural enemies (predators or competitors)
Realized niche
part of fundamental niche that an organism occupies as a result of limiting factors present in its habitat
Fundamental niche
full range of environmental conditions and resources an organism can possibly occupy and use when limiting factors are absent in its habitat
Allee effect
correlation b/n population size/density and the mean individual fitness of a population or species
Morphological species concept
based on morphological similarity
Biological species concept
groups of actually/potentially interbreeding natural populations that are reproductively isolated from such other groups (producing viable/fertile offspring and reproductive isolation, which allows independent evolution and is critical for speciation)
Speciation
origin of two species from a common ancestral species with the evolution of biological barriers to gene flow (one lineage splits to two sister species; sister lineages are the same age)
Node
point when one lineage splits into two
Allopatric speciation
new species arise from geographically isolated species
Sympatric speciation (sym=same)
new species arise from the same geographic region
Ecological speciation
host or habitat speciation, disruptive selection, assortative mating?
Polyploidy
genetic mechanism for abrupt reproductive isolation and speciation
Autopolyploidy
duplication of one species’ genome (e.g. diploid becomes tetraploid)
Allopolyploidy
hybridization of two species followed by genome duplication
Dobzhansky-Muller incompatibility
breakup of “coadapted gene complexes” causing independent mutations at interacting epistatic loci in different isolated populations
Post-zygotic reproductive isolation
hybrid incompatibilities cause isolation b/n diverging species
> gertilization occurs and F1 zygotes are formed but are infertile, preventing gene flow b/n parental species
Hybrid inviability (post-zygotic reproductive isolation)
mating occurs, zygote is formed but due to genetic incompatibilities during development, the hybrid zygote won’t develop
Hybrid sterility
hybrid zygotes develop into adults, but are sterile (do not for viable gametes) so gene flow is not possible
Hybrid breakdown
fertile hybrids form b/n two species, but hybrids have low reproductive success or F2 offspring are sterile
Pre-zygotic isolation
prevents fertilization
Geographic isolation (allopatry)
allopatric species have little opportunity for mating; species with low dispersal ability can be isolated by short distances
Ecological isolation
if two sympatric species use different habitats, they will rarely encounter each other; might be reprodctively compatible but they never actually meet so they are reproductively isolated
Temporal isolation
species that breed at different times of day, at different seasons or years cannot mate
Behavioral isolation
many organisms recognize members of their own species using highly specific courtships behaviors, songs, chemical signals or visual cues
Mechanical isolation
regardless of how hard males and females try to mate, they are so mismatches anatomically that they cannot consummate the act
Gametic incompatibility
even if mating is successful, gametes are incompatible and do not fuse to form a zygote
Evolutionary radiation
rapid proliferation of many species from a single ancestor due to key innovations, ecological specialization, sexual selection, vacant ecological niches
Adaptive radiation
species adapt to different ecological niches
Key innovation
an adaptation which enhances the diversification rate of a lineage
How do communities assemble?
- newly created habitat
2. disturbance (he removal of organisms by physical/biological process
Succession
pattern of changing species composition as a result of colonization and species interaction in a new habitat or after a disturbance
Primary succession
a substrate that does not have any living organisms or legacy of former living organisms
Secondary succession
a substrate that has been disturbed but contains a legacy of organisms that lived there prior
Cyclical succession
succession due to recurring (cycle=cyclical) events (e.g fire) or changing interactions b/n plants and animals
Indirect effect
a change in the abundance of a species resulting from its interaction w/ another species which is affected by a third species
Keystone species
species that have a major effect on community structure and an effect disproportionate to their abundance; has low biomass
Foundation species
species that have a major effect on community structure by virtue of their high biomass and habitat-forming characteristics
Maintenance of diversity
- Niche partitioning
- Intermediate disturbance, predation, and productivity hypotheses (Goldilock hypotheses)
- competitive intransitives
- fluctuations in environmental conditions change faster than the time required for competitive exclusion can promote coexistence
Intermediate disturbance hypothesis
only k-selected species survive low disturbance frequencies, only r-selected species survive high disturbance frequencies, both can survive medium disturbance frequencies causing them to coexist
Intermediate predation hypothesis
only competitively dominant species survive in low predator density, well defended species in high predator density, many species coexist in medium predator density
Intermediate productivity hypothesis
only a few species survive when there is low nutrient availability (harsh condition), only competitively dominant species survive where there’s high nutrient availability and many species coexist where there’s “just right” nutrient availability
Competitive intransitives
opposite of competitive transitive (A beats B, B beats C therefore A must beat C/has an order); has no order (e.g) rock, paper, scissor)
Ecosystem services
capacity of ecosystems to provide goods and services that satisfy human needs, either directly or indirectly
Provisioning services
any time of benefit to people that can be extracted in nature
e.g. water, food, timber, medicine, etc
Regulating services
benefit provided by ecosystem processes that moderate natural phenomena
e.g. water purification, decomposition, pollination, carbon storage, erosion control)
Cultural services
a non-material benefit that contributes to the development and cultural advancement of people
e.g. recreation, creativity
Eutrophication
excessive richness of nutrients in a lake or other body of water due to run off of nitrogen from land (dense growth of plant life and death of animal life)
Scientific evidence to reconstruct the history of life
fossils in sedimentary rocks, physical dating methods (radioisoptopes, paleomagnetic dating), phylogenetic trees and molecular clocks
Suess effect
signify the decrease in C14 in atmospheric CO2 owing to admixture of CO2 produced by the combustion of fossil fuels (more C12 in atmospheric CO2)
History of life (How do we know?)
- fossils in sedimentary rocks
- physical dating methods (radioisotopes, paleomagnetic dating)
- phylogenetic trees, molecular clocks
Geophysical events
history of life
- tectonic events (moving continents, volcanic eruptions)
- climate change
- changing sea level (caused by climate change)
Major biological events (history of life)
- origin of life
- rise of photosynthesis and atmospheric O2
- rise of eukaryotes
- rise of multicellular organisms
- diversification of phyla (major lineages)
- colonization of land and air
- mass extinctions followed by new radiations
Cenozoic
recent life
Mesozoic
middle life
Paleozoic
old life
Cyanobacteria
crucial prokaryote of the carbon, first to produce atmospheric oxygen > aeroic metabolism > birth of photosynthesis > birth of larger (more complex) organisms
Ecosystem engineer
an organism that alters ecosystem structure and/or function
Endosymbiotic theory
eukaryotes are originated from prokaryotes
>ancestral host made aerobic bacterium its endosymbiont, which led to the birth of the mitochondria
>FOR PLANT LINEAGES: ancestral host made cyanobacterium its endosymbiont, which led to the birth of chloroplast
Endosymbiont
any organism that lives to mutual benefit within the body/cells of another organism
Symbiotic
involving interaction b/n two different organisms living in a close physical association (can be mutualistic, commensalistic, parasitic)
Precambrian period
BEFORE PALEOZOIC
multicellular aquatic organisms evolve, more O2 levels
Cambrian explosion
PALEOZOIC 1
rapid appearance of most modern aquatic animals (caused by oxygen, sexual reproduction, regulatory genes, eyes, predation)
Ordovician period
PALEOZOIC 2
diversification of marine organisms
Mass extinction # 1
LATE ORDIVICIAN PERIOD
cooling, glaciers, dropping sea level (loss of habitat), 75% species lost
Challenges of colonizing land
structural support water and nutrient acquisition desiccating atmosphere (dry) gas exchange mobility mating and gametic dispersal
Silurian period
PALEOZOIC 3
rise of jawed fishes, land plants and terrestrial arthropods
Devonian period
PALEOZOIC 4
life takes off on land > soil formation bc roots, insects and amphibians appear
Mass extinction #2
LATE DEVONIAN PERIOD
climate fluctuations, marine anoxia (absence of oxygen), loss of reef ecosystems (loss of habitat), 75% species loss
Carboniferous period
PALEOZOIC 5
domination of horsetails and ferns (most fossil fuels of today), first reptiles appear, insect diversity (giant bugs)
Permian period
PALEOZOIC 6
reptiles, giant amphibians and insects coexist and are diverse, Pangaea, volcanic activity
Mass extinction # 3
PERMIAN-TRIASSIC (“THE GREAT DYING”)
volcanic eruptions disturn carbon cycle, warming, anoxia, acidification, ozone depletion, toxic metal poisoning, oxygen 15%, about 90% species extinct, ENDED PALEOZOIC ERA
Triassic period
MESOZOIC 1
breakup of Pangaea, conifers and ferns dominate forests, radiation of reptiles
Mass extinction #4
TRIASSIC-JURASSIC
massive volcanic eruptions, destabilization of carbon cycle, rapid increase of atmospheric CO2 (rapid global warming), acidification (loss of shelly marine species), 65% of species go extinct
Jurassic Period
MESOZOIC 2
diversification of dinosaurs and fishes, first flowering plants
Cretaceous period
dinosaurs dominate, rise of mammals and flowering plants
Mass Extinction # 5
K/T (Cretaceous-Tertiary) ASTEROID IMPACT
75% species extinct including avian dinosaurs, ENDS MESOZOIC ERA, OPENED UP ECOLOGICAL NICHES FOR DIVERSIFICATION IN CENOZOIC
