7B week 8-10

The carbon cycle

biological process that shuttles carbon among rocks, soil, oceans, air and organisms 

-includes long term and short term carbon cycle

keeling curve

-pattern fo co2 concentration inthe atmosphere from 1950’s onward

patterns observed

• spring; co2 reaches a high point

• fall; declines about 6ppm

• summer; when removal of co2 occurs, probably about 6ppm

• winter; slow build up of co2

the removal of co2 does not balance the increase

-over every year there is an increase in overall co2

short term carbon cycle

-determined by photosynthess and respiration

• photosynthesis uses sunlight to reduce co2 to carbs while oxidizing water to o2 while respiration runs the same reaction in reverse,forming the cycle 

explain the seasonal differences of co2 concentration (why is this trend northern hemisphere dominant?)

• there are more plants and lands in the northern hemisphere than the southern hemisphere

• In areas of the world all excluding the equator (that does not expeirence eseasonal differences) the different activit yof respiration is what is repsonsible for the co2 oscillations

• -in the summer there is high photsynthesis and inthe winter htee is low photosynthesis

• global co2 declines through the northern summer (when rates of photosynthesis are highest relative to respiration) and then increase through fall and winter (respiration dominantes) 

what explains the gradual increase iin co2 concentration over the years?

pieces of evidence that hint that the yearly increase is due to human acitviity

-human activity, atmospheric co2 inputs and outputs were approximately in balance until the industrial revolution

• Suess’s measurements of the atmosphere; isotopic composition of atmospheric co2; the only isotope ratio contained int he organic matter of organism (fossil fuels when burned) matches the shift in carbon isotope ratios

• past history using ice bubbles in glaciers that trap relative amounts of co2 in each time point; shows that co2 levels began to increase only starting from the 1800’s

not all co2 released by human activity is released in the air; where does it go?

-missing cabronhas been stored as inorganic carbon int he form of bicarnonate, carbonate ions dissolved in the oceans

-taken up by vegetation and soils

Long term carbon cycle

before human activity, what explained the oscilation of co2 levels from 285 to 180 ppm in parallel with flacial expansion and retreat

the proposed mechanisms commonly suggest interactions involving the ocean’s capacity to store large amounts of inorganic carbon, especially during glacial times.

Resevoirs (long term carbon cycle)

places where carbon is stored on the earth; organisms, the atmosphere, soil, the oceans, and sedimentary rocks. Both biological and geologic processes cycle carbon back and forth among these reservoirs.

main forms of carbon in 1. soil,2.ocean 3. sediment and sedimentary rock

1.soil; slowly decaying organic compounds

2. inorganic carbon dissolved in water

3. calcium carbonate minerals (limestone), organic matter preserved indefimentary rocks (SEDMENT AND SEDIMENTARY ROCK IS THE LARGEST RESEVIOR)

fluxes

the rate at which carbon flows from one resevior to another;descibes methods of storage and release between resevoirs

how is co2 in the long term carbon cycle released

how is it stored back in

what is the process that connects the release and sotrage processes together?

release

• oxidation of coal, oil and ancient organic matter from the sediment

• volcanic activity

storage

• chemical weathering

• organic burial on land

• sefimentation of organic shells and skeletions

• burial of organic matter

connection process

• subduction (plate tectonic activity) , sedimentary carbont hat has been buired can return to the mantle through which one plate sinks beneath another and rises up

climate (general def)

the long term average weather over an area

how is climate determined

solar radiation-direct temp

global patterns of wind and ocean circulation-distirbution of direct heat across globe

earths topography- climate changes within each area due to differences in elevation

what determines the surface temperature of a patch of earth

-the angle at which solar radiation stickes the surface (detemrined through the spherical shape of the earth that creates natural angular differences)

-equator experiences harsher solar radiation as the beam is more direct (less surface area), in contrast to poles, where the curvature of the earth is more, thus the solar radiaiton can spread out more

what explains seasons

-the tilt of the earth 23.5, and its axis around the sun

topography

the physical features of Earth’s surface

— also contributes to global temperature patterns. Even at low latitudes, mountaintops can have glaciers, reflecting the fact that temperature declines with increasing elevation

Hadley cells

Large-scale atmospheric circulation cells where hot air rises at the equator, flows toward the poles, sinks at around $30^\circ$ latitude (North and South), and flows back toward the equator.

• Context/Impact: * Equator (0degrees): Rising air cools and drops intense rain, creating tropical rainforests (high biodiversity).

  • Deserts (30 degrees): Sinking air is dry and warm, creating major desert biomes.

  • Drives the baseline distribution of terrestrial biodiversity by establishing global precipitation zones.

what are the prevailing winds, and why does it occur (wind patterns)

-wind patterns (the direction of westerlies, easterilies, trade winds) are deifned by the rrotation of the earth around its axis

• the equator moves slower than the poles

• Surface winds that blow consistently in a specific direction over a particular region of Earth, driven by the combination of Hadley cells and the Coriolis effect.

  • Key Examples: * Trade Winds: Blow from East to West toward the equator (between 0 and 30).

    • Westerlies: Blow from West to East in the mid-latitudes (between 30 and 60).

  • Context/Impact: They distribute moisture and heat across the planet, directly influencing regional climates, weather patterns, and the distribution of biomes.

coriolis effect

• Back: * Definition: The apparent deflection of moving air (and water) caused by the rotation of the Earth.

  • Direction of Deflection: * Northern Hemisphere: Deflects movement to the right.

    • Southern Hemisphere: Deflects movement to the left.

  • Context/Impact: Prevents air from moving in a straight North-South line within Hadley cells. Instead, it curves the moving air, breaking global circulation into distinct wind belts.

heat pattern observed in water

At high latitudes, surface ocean waters cool enough to sink beneath warmer, less dense ocean waters, with the colder waters sinking to the deep ocean where they begin to move slowly toward the equator.

circulation of winds and rainfall

-warm air carries more h2o, when cooled, h2o is released as precipitation

-rain fall occurs in the process of air becoming warm to cool

• water fall does not occur at places where air becomes cool to warm (this takes up moisture from the surroundings, leading to airditiy)

rain shadow and relationship to climate precipitation

mountains impose a regional pattern of rainfall

as wet air moves from the ocean up into the mountains, it cools, releasing its moisture as precipitation.

Moving past the mountains, air masses descend, warming as they go and taking up water vapor.(For this reason, lands in the rain shadow of the mountains are arid)

population

all the individuals of a given species that live and reproduce in a particular place, must be in the same geographical place ( same species in different islands would not compose a population)

population size

the is the number of individuals of all ages of a certain species alive at a particular time in a particular place.

geographic range of a population

the area over which that population is spread

-reflects the range of climates a population can tolerate and how many other species the population encounters

range and size of a population determines what

population density. pop size/range

how can raw counts of pop density be misleading

-depends on how organisms are distributed

-if you wanted to use it accurately, the only distribution that would be useful would be random distribution

random, clumped and unifrom distribution

random; a new individual has an equal chance of occupying any position within the range, and the location of one individual has no influence on where the next individual will be found.

clumped: , resources are distributed patchily within the range, or the chances of a new individual’s survival are enhanced by the presence of other individual

unifrom: n occurs when one individual of a population prevents another from settling nearby, such as when all individuals depend on the same set of limited resources.

how to esstimate population size

using population density, you estinate the popiulation siz for the actual total area of the habitat

mark and recapture (equation?)

-way to take samples and esimate population size for mobile organisms

A method in which individuals are captured, marked in a way that doesn’t affect their function or behavior, and then released. The percentage of marked individuals recaptured later enables ecologists to estimate population size.

-assumption; no immigration or emigration, the population size remains the same size between first and second sample

eqution:

To determine the population size (N), the total number of marked butterflies and unmarked butterflies caught on the second day (C) is divided by the number of recaptures (R). This number is then multiplied by the number of butterflies marked on the first day (M), as follows:

N= (C/R)xM

delta N equation with counts of brith, death, immigrants and emigrants

delta N= (Birth-death) + (Immigration -emigration)

per capita growth rate (what does it mean when its neg and positive)

symbolizied by ( r)

-the change in population size delta N in a griven period of time t divided bt the stize of thepopulation N

(dN/dt)/N = r

the average number of offspring per individual

(+)= the pop increaes in size

(-)= the popoulation decreaes

0= the popuaiton size does not change

most population models and equations assume that and account for only..

-assume that the population is isolated with no immigration into or emigration out of the population

-only focus on birth and death

continuous growth

-defined by non sybchrnozized lifec cyles between generations

• organisms develop at different times and reproduce at different times, there can be organisms form the previous generation still reproducing with the organisms from the new generation

• defines logistic and exponential populaiton growth models

exponential growth (commonly seen in what organisms)

Exponential growth occurs when the growth rate is constant, meaning the population grows in proportion to the number of individuals.

• continuous growth

• no carrying capacity

• j shape

• delat N/delta t= rmax N

organisms

• seen in small population when resoources are abundant

• no environmental factors that limit population growth

what is r in population growth model equations

the per capita growth raate at an instant of time (in comparison to average)

-called the instrinsic rate ofincrease

instrinsic rate of increase

The per capita growth rate; the maximum rate of growth when no environmental factors limit population increase.

what is rmax in population growth models

rmax; the instant rate of increase when there are no environmental faqctors that limit population growth

how can we caluclate population size (N) at any time t for exponential growth model

Nt=N0e^rt

what happens as the rate of growth slows

the death rate increases to equal to birth rate

carrying capacity (k)

what factors can change K

what factors can KEEP a population from reaching k

• the maximum number of idnivduals that habitat can sustain indefintiely without environmental deterioation,

factors that can change k

• limited by the availability of the environmental resources (not predation etc, just resources) that are available to support these needs

• anything that changes available resources or usable habitat changes K. (density dependent and independent)

factors that can prevent a population from reaching k

• Density-dependent (get stronger as population grows):

  • Predation

  • Disease / parasites

  • Intraspecific competition (competing with own species for food/mates)

  • Accumulation of waste/toxins

  Density-independent (hit regardless of population size):

  • Sudden storms, frost, or floods killing individuals

  • Habitat disturbance

  • Human hunting/harvesting

logistic growth (equation for slope)

-s shaped curve

-even though the population does not always have rmax as growth rate like pure exponential growth, use rmax since this value is already limited by k-n./n

-where a population grows at rmax (and exponentially) until reaching K, where it levels off and rmax decreases (rmax value is limited by k-n/n)

dn/dt= rmax ((K-N)/K)N or deltan/deltat= rmax(1-n/k)n

density dependent factors

Describes processes affecting populations that are influenced by the number of individual organisms, such as the use of resources or susceptibility to predation or parasitism.

-affects population growth rate

-shoes a smooth continous decrease in population size

density independent factors

Describes factors such as severe drought that influence population size without regard for the density of the population.

-can still affect population growth rate

-often shows instantaneous, rather than gradual, drops in population size, and these changes can occur at different starting densities.

to predict future changes in populations what is considered?

birth rate

expected longevity

proportion of individuals in a population that is able to reproduce

-which can be obtained from the age structure of a population

age structure

The number of individuals within each age group of a population.

Estimating the number of individuals of differing ages enables ecologists to predict whether the size of a population will increase or decrease.

age structure that is pyramid shaped tells us…

age strurcture that is more rectangular tells us…

A growing population usually shows a pyramid-shaped

stable (not changing) population shows a more even distribution of age classes (rectangular)

cohort and survivorship

cohort; A group of the individuals born at a given time.

survivorship: The proportion of individuals from the initial cohort that survive to each successive stage of the life cycle is called survivorship. (tells us mortality)

type I survivorship curve

-low morality at early ages

-seen in humans and larger mammals

-seen in k strategists

what do survivorship curves show

plot of age versus percentage of organisms surviving

type II survivorship

• linear

• inividuals are likelky to die at any point in life

• seen in birds and small mammals

type III survivorship

• high mortality in early parts of life

• seen in insects etc.

• r strategists

• these organisms give birth to a lot to increases the probabiltiy that they will have at least offspring that survives

r strategists

• a species that produces large numbers of offspring but provides few resources for their support.

• reproduce at rates approaching , the maximum intrinsic rate of increase.

• type II and III

• undergo external fertilization

• s evolve in unstable, changing, and unpredictable environments.

k strategists

• type I survivorship curve

• produce only a few young and are K-strategists because their population densities commonly lie near the carrying capacity K.

• A species that produces relatively few young but invests considerable resources into their support.

• internal ffertilization

• n stable, unchanging, and predictable environments, where there tends to be more crowding and larger populations

life history tradeoff concept

Because organisms only have a finite amount of energy and resources, they cannot maximize everything. Resource limitations force tradeoffs between survival, growth, and reproduction. For example, a plant can produce a few large seeds (high survival chance per seed, huge energy cost) or thousands of tiny seeds (low survival chance per seed, low energy cost per seed), but it cannot produce thousands of massive seeds.

metapopulation

A large population made up of smaller populations linked by migration.

-includes mainlands and issland populaitons

-linked by occasional movements of individuals among them along corridors

-all of the same species

extinction rate and metapopulations

A metapopulation is a "population of populations" linked by immigration and emigration.

• Extinction Risk: Small subpopulations (sinks) have a high risk of local extinction due to small sizes and poor resource quality.

• The Rescue Effect: High dispersal ability allows individuals from high-quality patches (sources) to migrate and save dwindling sink populations from extinction.

• Corridors: Narrow strips of habitat that combat habitat fragmentation by maintaining connectivity, lowering extinction rates, and allowing for re-colonization.

habitat patch and island

• An area of continuous, relatively homogenous habitat that provides the specific resources and conditions a species needs to survive and reproduce. It is surrounded by a "matrix" of distinctly different, unsuitable habitat.

• Context/Examples: A patch of forest surrounded by agricultural cornfields, or a park in the middle of a paved city.

• Key Concept: Habitat patches form the individual pieces of a metapopulation. They are usually terrestrial and often created by humans via habitat fragmentation

island is not always water; Ecologists commonly generalize the term “island” to refer to any habitat patch that is surrounded by a substantial expanse of inhospitable environment

source and sink populations

• Source Populations: High-quality habitats where birth rates exceed death rates. These populations produce a surplus of individuals that emigrate to other patches. can rescue sinks through recolonization or dispersal

• Sink Populations: Low-quality habitats where death rates exceed birth rates. These local populations would go extinct if not for a constant influx of immigrants from source populations.

law of tolerance and three zones of tolerance

An organism's geographic distribution is limited by its ability to tolerate variations in environmental factors.

Zone of intolerance — These are the conditions at either extreme end of the spectrum, beyond which the species simply cannot survive. If a fish requires water between 5°C and 30°C, temperatures below 5° or above 30° fall into this zone — the organism dies or cannot exist there at all.

Zone of physiological stress — Just inside the lethal limits, conditions are technically survivable but costly. The organism is alive, but it's working hard just to maintain basic functions. Growth slows, reproduction drops off, and the individual is more vulnerable to disease or predation. Think of it as the organism running on fumes — technically functional, but not thriving.

Zone of optimum — This is the middle range where conditions are ideal. The organism grows well, reproduces successfully, and is most abundant. This is where you'd expect to find the highest population densities of that species. It sits between the two stress zones and represents the "sweet spot" for that environmental variable.

how to interpret a tolerance curve

plot a species' population response against an environmental gradient (like temperature, salinity, or rainfall), it creates a bell-shaped curve divided into three distinct zones. These zones map directly to where you will find the species on a map.

he model applies to any abiotic factor — temperature, salinity, pH, light, moisture — and each species has its own unique tolerance curve for each factor. A species' realized distribution in the real world is shaped by whichever factor is most limiting (Liebig's Law of the Minimum is the related idea here). Even if temperature is perfect, if soil pH is outside the tolerance range, the species won't be there.

-the factor level incorporates all components of abiotic factors

Niche

The combination of a species’ physical habitat and its ecological role in that habitat

fundamental niche

es the full range of climate conditions and food resources that permit the individuals in a species to live

It is defined solely by abiotic factors (e.g., temperature, water availability, pH). It represents the theoretical, maximum range of conditions and resources a species could survive in without any interference or limitations from other organisms

realizied niche

The actual resources and habitats used by a species.

The actual, restricted space a species occupies in nature due to interactions with other organisms (like competition, predation, and mutualism) is called the realized niche.

phylogenetic niche conservatism

The observed similarity in closely related species of some aspect of their niches, indicating its presence in their common ancestor.

how to analyze fundamental vs realizied niche graphs

-graphs that define fundamental and realizied niches are on tolerance graphs

-the overlap zone between fundamental niches is the compeition zone

-the one with the higher curve in the overlap range outcompetes the other, making the losing species pushed to one side; the weaker species niche becomes the nonoverlapping protionof its fundamental niche

-a large shift for one species in its new realizeid niche means strong compeitiotn and smallshift means weak

-farther apart peaks means less compeition and easier coexsistence

the realized niche is always equal to or smaller than the fundamental niche — never larger. (EVEN the WINNING SPECIES PEAK DIPS SINCE ITS PAYING A COST IN COMPETING→ SHOWS THAT COMPEITTION ALWAYS LEADS TO A COST FOR BOTH)

-of neither species wins, (coexsistence) then both peaks may drop a little in the shared region, but both species persist across the full gradient.

antagonism

, interactions in which at least one participant loses more than it gains.

-compeititon, paratism, predation

competition

An interaction in which the use of a mutually needed resource by one individual or group of individuals lowers the availability of the resource for another individual or group. abiotic factors and biotic factors are the resources

-for both individuals undergoing compeition, it is generally a lose-lose situation for both individuals involved, even the winning species loses; Individuals either lose access to resources or they spend energy on securing resources that otherwise could be used for reproduction.→ struggle for exsistence

intraspecific competition

Competition between individuals of the same species.

• defines the tension between the intrinsic rate of increase and the environmental carrying capacity

• the increase in interspecific compeition is a major reason why population growth slows as the population approaches the environments carrying capacity

interspecific competition

Competition between individuals of different species.

competitive exclusion (can lead to….)

-defines that that two species cannot occupy the exact same niche at the same time, also applies to overlapping niches (they work to minimize overlap)(but overlap is still allowed)

through comptetiton; , one will either become extinct in that place or change its niche. (change could mean simply shifting)

can lead to..

• change of fundamental niche to realizied niche, smaller niche for both species

• local extinction of the other species

resource partioning

-driver of coexsistence

-A process in which species with overlapping niches diverge over time to minimize the overlap.

-it allows similar but diffferent species to coessit in the same niche (their fundamental niche shifts) as they diverge

-driver of diversification and speciation

-parodxially, competitive exclusion can lead to divergence and speciation through learned resource partiioning

predation

is a type of interaction in which one organism, a predator, consumes another, its prey. In this interaction, the predator benefits at the expense of the prey

-one of them benefits and the othe loeses (unlike compeittion which both species are at a aloss)

-stable equillbrium between predator and prey relationship; one of them dips and the other also dips but not at the same time, its a reaction between each other

what is a requirement for predator prey systems to be stable and what are the effects of this relationship

Predator–prey systems can be stable if there are sufficient areas available where prey can escape predators, at least temporarily.

• can effect non prey species; i.e e, predators can limit the population sizes of their prey to the extent that competitive exclusion does not occur between the prey and a competing population

paratisism

-An organism that lives in close association with another species, consuming or gaining nutrition from host tissues, generally without killing the host.

-different from predation as it does not instantly kill the host

-the efect ont he other species population is long term and can limit them from reachig carrying capscity but does not dramticallly reduce population

herbivory

the consumption of plants

when does a relationship between species become mutualistic

When the benefits for each participant outweigh their costs,

An interaction between two or more species that benefits all→ for mutalism, the relaitonship MUST benefit both species

symbioses

A close interaction that has evolved between species that live together, often interdependently.

symbioses can drive recipriocal adaptations between the two species and thus….

develop long term coevolution

can mutualism also drive resouorce partiioning and speciation?

exmaple 1: prevention of compeition→ mutualistic networks (such as plant-pollinator or host-microbe systems), high densities of species often gather in the same area. To avoid intense competition for mutualistic services (e.g., vying for the same pollinators), species undergo niche differentiation

example 2: finding a new partner→ Mutualism facilitates speciation primarily through divergent selection and partner shifts. When a lineage within a mutualism evolves to rely on a new partner or a specialized mutualistic strategy, it begins to diverge from the original population

obligative mutualism and factulative mutualism

obligative; In ecology, a type of mutualism in which one participant requires the other to survive. In metabolism, a means of gaining energy or carbon that is required by the organism; that is, it has no other options, as in an obligate photoautotroph.

faculative; In ecology, at type of mutualism in which one or both sides can survive without the other. In metabolism, a means of obtaining energy that is sometimes but not always used.

current obligative realtionships could have ev olved from faculative relationships over time

commensalisms

An interaction between species in which one partner benefits with no apparent effect on the other.

ammensalism

n which one species in an interacting pair is harmed with no apparent effect on the other.

facilitation (difference between commensalistic and mutualistic relationships between two species?)

An indirect interaction between two species in which one species changes the environment in such a way as to benefit another species.

-can be seen in both commensal and mutualistic relationships

commensalitc and mutualistic relationships are diefned by direct sepcies to species interactions while factiotialiton is environmentally effecting

community

the set of all populations of two or more different species found in a given place at a particular time.

Populations in a community are connected by their various interactions as well as by their physical location.

requirements for different populations of species in a community

0cannot have the exact same geogrpahical distribution

if actvities are the same/ function in their niche, then theya lso differ in time of doing the activity (differetn insect pollinators)

biodiversity

Biological diversity; the TOTAL number of species, or, more broadly, the diversity of genetic sequences, cell types, metabolisms, life histories, phylogenetic groups, communities, and ecosystems.

species richness

the number of species present in a particular area,

how is species richness measured for communities that are very large

s. In terrestrial environments, the number of plant species is often a good predictor of total species diversity. For example, there are approximately four times as many animal species as plant species known on Earth. Therefore, scientists estimate the numbers of animal species by multiplying the number of plant species by 4.

aspects of biodiversity

species richness

species eveness

species eveness

relatiove proportions of individual species in a community in comparison to the total

effect of species eveness and richness on extinction rates and suvivorship

the more even and more rich, the stronger the community is agaisnt surviving distruptive factors

keystone species

Pivotal populations that affect other members of the community in ways that are disproportionate to their abundance or biomass.

-the limiantion of this keystone species shifts the relationships and the proportions and species richeness eveneess of a communtiyb

succession (primary and secondary)

In ecology, the process of species replacing one another in time in a predictable sequence; each species modifies the habitat by affecting the environment or changing the community structure, creating opportunities for other species

primary: the intital colonization of a previously uninhabited areasecondary: reestablishment of communities following disturbance

-species colonize and transform the habitat in a predictable sequence that reflects the adaptations of participating species.

climax community

A mature assembly of species, a final stage in succession, in which, in the absence of environmental disturbance, there is little further change in species composition.

island biogeography and species equillbrium

-why are islands interesting to observe sepcies diversity and community

* The Equilibrium Model: The number of species on an island ($S$) is a dynamic balance between Colonization Rate (new species arriving) and Extinction Rate (established species dying out).

• As Species Richness Increases: * Colonization decreases (fewer remaining immigrants are "new" species; less empty space).

  • Extinction increases (more intense interspecific competition and smaller population sizes).

• The Two Physical Drivers:

  • Island Size: Affects Extinction. Large islands = lower extinction (more space/resources).

  • Island Isolation: Affects Colonization. Near islands = higher colonization (easier to reach).

-what is species eqillbirum in an island and how is it determined

species number equillirum; the point of intersectionbetween rate of colonization and extinctio, species diversity is at equillvirum

• This does not mean that no new species will colonize the island, but instead that the establishment of a new colonist species will replace the extinction of one already in place. There is generally turnover in species composition through time.

theory of island biogeography (what do they mean about hte number of species that CAN occupt an island)

A theory that states that the number of species that can occupy a habitat island depends on two factors: the size of the island and the distance of the island from a source of colonists.

-basically the size and distance of the island determines the equillbrium point (whihcis defined by rate of colonization and extinction)