Biology 1D Environment

snowball earth hypothesis

earth’s surface entirely frozen and oceans covered by ice

snowball earth competing theories

rocks formed near equator and deformed + dropstones NEAR EQUATOR vs. rock formed and deformed EVERYWHERE

creator of snowball earth hypothesis

Paul hoffman

skeptic of snowball earth

nick christie-blick (slushball)

how did earth get out of snowball earth

volcanoes, greenhouse effect, geothermal vents, gaps in melted ice, cap carbonates

modular organism

plants - build indefinitely

indeterminate

unspecialised

determinate

specialised

inflorescence

group of flowers on stem

cladode

leaf-like structure, formed from a stem

geranium lucidum

different color leaves - sun exposure and stress

cheese plant/monstera

holes - to appear previously eaten

rheum nobile

white leaves - high uv radiation/conserve warmth

how many cells in a human

~7- trillion —> 55% (31 trillion contain DNA)

microbiome

community of microorganisms that live in specific environment

bioaugmentation

adding microorganisms to contaminated environments to degrade pollutants

microbiome interactions

competition for space, parasitism, predator/prey engulfing, social signal

quorum sensing

bacterial communication, exploiting new niches (biofilm formation)

succession

communities age over time in response to environment - abiotic and biotic agents

birth mode and microbiome

influence on gut - c section vs birth canal can have short term effects on matching maternal microbiome

how to change microbiome

diet (probiotics), health/treatment, hormones, fecal transplants, antibiotics/chemo

rewilding the gut

fecal microbiome transplant, does not usually work, high possibility of mismatch; adding a climax community to a bare environment so it doesn’t work

why are human microbiomes different from each other

different parts of the world have different dominant types, nature vs. nurture

human microbiome project

trying to characterize a health microbiome - difficult to define

lactobacillus

lactic acid producing bacteria - marker of health

4 proven climate change facts + 2 causal relationships

CO2 traps heat, humans emit CO2, increasing CO2 in atmosphere, global temperatures rising —> CO2 increase due to humans and causing climate change

current consensus for climate change

less heat escaping atmosphere than before and reduction matches CO2 plus CH4 absorption wavelengths

niche

summary of organisms’s tolerances and requirements - first defined by grinnell in 1914 - how not where an organism lives

competitive exclusion principle

gauses 1934 theory - complete competitors cannot exist, species use different parts of a habitat - 2 species using same limiting resource in some way cannot coexist indefinitely, the greater the difference the more likely to coexist (avoid by keeping species at low density and intra>inter)

n dimensional hypervolume

defines boundaries of life and multidimensional - defined by GE Hutchinson 1957 - addresses ways in which tolerances and requirements interact to define conditions and resources needed (temp, humidity, pH, windspeed, water flow, daylight, precipitation, etc)

resource partitioning

ecologically similar species living in same habitat utilize different resources

spatial/temporal/morphological/conditional partitioning

similar species use same resource but are separated in space, time, morphology, or ability to use resource

niche construction

organism modifies own niche to increase fitness important for natural selection

extended phenotype

not limited to biological processes but extended to all effects gene has on environment

fundamental niche

overall potential niche of a species, allowing it to have viable population

realised niche

more limited spectrum of conditions and resources that allow a species to persist - role species fills in reality - restricted by interspecific competition that reduces survival

carrying capacity (K)

how many individuals a niche can support - species can be limited by others occupying same space therefore lowering K

how do competing species coexist

one wins and higher K more competitive, another wins, either could win and then one goes extinct (higher inter low intra), both coexist (low inter high intra)

two ways to prevent competitive exclusion

species at low density + species inhibits own population growth more than its competitor

two mechanisms of competitive coexistence

equalizing (keep density of strongest competitors low - predation) + stabilizing (cause intraspecific competition > interspecific —> species increases when rare - niche differentiation)

evolution and niches

evolution → ecology (related species inherit similar ecological traits, phylogenetic niche conservation) vs. ecology → evolution (competitive exclusion principle. adaptation to new niches and reproductive isolation, speciation and extinction)

community

assemblage of species populations that occur together at same place and time; defined arbitrarily based on interests of ecologists studying them using physical or biological characteristics

ecological community

collection of organisms found inhabiting a defined area - understand origin, maintenance, and consequences of diversity, measures of diversity and relative species abundance

how to define communities

taxonomic affinity, guild (group of species using same resources), functional groups (subset of community includes species that function in similar ways but dont use same resources, defined based on sets of species traits useful to explain ecosystem properties)

ecosystem service

something functional group does for community to aid other species

trophic levels

position organism occupies in a food chain; energy flows up

national vegetation classification

1975 book to classify plant structure

functional feeding groups

predator, omnivore, collector, grazer, shredder, piercer

community structure

set of characteristics that shape a community; descriptive in nature but provides necessary quantitative basis for generating hypotheses and experiments to better understand communities

species richness

number of species - measured by species accumulation curve, influenced by degree and length of isolation, size of island, habitat suitability, location relative to ocean currents, serendipity, human activity

species evenness

abundance of species (common and rare)

species diversity

measure of both richness and evenness

Shannon Diversity index

estimate of species diversity (H= - ∑(Pi*(lnPi) ) - higher H value indicates more diversity (usually between 1-3)

biodiversity

richness and diversity of species; measured at all scales

biogeography

study of variation in species competition and diversity among geographic locations

latitudinal diversity gradient

more diversity in low latitudes - higher productivity and rate of diversification

species area curves

as size of habitat increases the number of species increases

Equilibrium Theory of Island Biogeography

McArthur and Wilson 1967 - number of species on an island depends on balance between immigration, dispersal rates, and extinction balance in dynamic; rates vary by size and isolation

disharmony

relative proportions of different taxa are not the same on islands as mainland

assembly rules

patterns in developing and establishing communities (predators cannot invade new community without prey; only certain combinations exist in nature; different rules for different areas)

incidence functions

relationship between species and island size

island biogeography

small island: high extinction, low immigration, low diversity
large island: low extinction, high immigration, high diversity
neighbor island: low extinction, high immigration, high diversity
far islands: high extinction, low immigration, low diversity

food chains

animals linked together by food, and all dependent in the long run upon plants

food webs

describes feeding relations among organisms in all or part of a community/ecosystem

trophic levels in food chain

primary producer (autotroph, detritivore, decomposer) → primary consumer (herbivore)→ secondary consumer (primary carnivore) → tertiary consumer (apex predator, secondary carnivore) - measure by number of lines + 1 between basal species and species of interest

links

lines between nodes that indicate predator/prey relationship and competition

nodes

single species/group

trophic position

nodes distinguished as basal, intermediate, or top predators

source webs

feeding relations among species from single food source

sink webs

linked by one top predator and what they eat

community webs

describe entire set of feeding relations

cycles and loops

species have reciprocal feeding relations

energy flow

energy created by autotrophs and flows through chain, passes up through each feeding link, energy lost with each transfer due to entropy, net energy will decrease with each level

trophic efficiency

how much energy is transferred up the foodchain (CE*AE*PE)

consumption energy

proportion of available energy ingested by consumers (In/Pn-1 ×100)

assimilation efficiency

proportion of ingested food that is assimilated by consumer via digestion (An/In *100)

production efficiency

proportion of assimilated food that goes into producing new consumer biomass (Pn/An *100)

Interaction strength

measure of the effect of one species’ population on the size of anothers

apparent competition

presence of multiple noncompeting prey species elevates predator abundance and increased predation pressure

trophic cascade

how effects at one trophic level can influence abundance of species at another (bottom up or top down), required to happen over minimum of three levels to fit description

keystone species

species tightly connected within food web

indirect effects

influence of one species, donor is transmitted through second species (transmitter) and third species (receiver)

direct observation

+: direct evidence, -: time, nature interference, bias, affected behavior, lose contact

scat analysis

+: direct evidence, repeatable, -: sick animals, contaminated, limited, digestion and decay rate, bias

gut content analysis

+: direct evidence, not biased towards large size, -: repeatability, killing animal, requires capture, invasive, only shows last meal

stable isotope analysis

+: direct evidence, not biased towards large size, repeatable, accumulate in flesh/bones, -: tissues needed, resource demanding, can be misleading

10% Rule

loss of energy at each step

individual efficiency

efficiency with which a typical individual turns its consumption into somatic growth

abiotic changes

waves, currents, wind, water supply, chemical composition, temperature, volcanic activity, disturbance: physically harms some individual and creates opportunities for others to grow and reproduce, unpredictable and one off event, stress: occurs when abiotic factor reduces growth or reproduction of individuals and creates opportunities for others, impede performance

biotic changes

negative interactions between species; competition, predation, herbivory, disease, parasitic, trampling

basics of succession

involves colonization and extinction of species in a community due to agents of change; influenced by: site conditions, events initiating succession, interactions of species, availability of colonists, seeds, weather conditions

pioneer stage

after a catastrophic disturbance

climax stage

an equilibrium stage with little change

primary succession

involves colonization of habitats that are devoid of life; slow with first arrivals, basic resources lacking; capable of withstanding stress

secondary succession

reestablishment of community in which most organisms have been destroyed; occurs after agents of change; surviving species very important

intensity

amount of damage and death caused

frequency

how often the change occurs

intermediate disturbance hypothesis

disturbance as a prevalent feature that influences community diversity; high and low levels disturbance reduce diversity and intermediate levels promote diversity

Facilitation Model

only pioneer species established, modification for later; dominant replace them

tolerance model

any species in succession could establish in present conditions; early modification has no effect; dominant will eventually replace