Test 3 Flashcards
What is an autotroph
Plants that can make their own food
Sessile
Can’t move
What are the elements plants need to live 4
Light
CO2
Water
Solid nutrients …not
Draw the photosynthesis thing
Co2 + h20 ——light—-> carbohydrate + 02
-the other way is cellular respiration ATP
Net primary productivity (npp)
C gained via photosynthesis - C lost via respiration =npp
Photosynthetic adaptations
Photosynthetic structured\s (green) are usually leaves
-take in c02 through stomata
-transpire : lose water through stomata
Impacts leaf breeakthing
Leaf size and shape - SA:V ration
Benefits of large leave is good for harvesting light and C02
Cost of large large is bad for overheating water loss by transpiration
Three photosynthesis
C3 photosynthesis
-rubisco is the enzyme that accepts c02
-high temp rubisco often captures o2 instead of c
C4 photosynthesis
-the enzyme PEP CARBOXLASE FORST ACCEPTS CO2 REducing photoresrpiration
CCA, PHTOT
-close stomata ain day to reduce water loss, open stomata at night to let in co2…but needs light so they store co2 as maleate until day
Evaporative cooling not always possible…
-need lots of water
—closing stomata shits off gas exchange
-trade-offf between water conservation and rapid growth
Palo Verde
-photosynthetic bark
-grow without water loss
Santa rite prickly pear
No leaves but it angles towards the sun set
Adaptations to episodic rain
-saguaro cactus
-shallow roots
-cam photosynthesis
-accordion pleated trunk allows expansion
-can absorb 800L
Root foraging
Low N vs high N
-search for nitrogen-fixing bacteria in soil
Leaf shape
More laminar flow-bad for gas exchange
More turbulent flow- good for gas exchange
-sun leafs would have more turbulent shape
Recursive digression
Convective cooling aided by turbulence
Population in calculation
Population size N is the number of individuals living in an area
-n/ares=pop density
Why care about N
Natural resource management
Conservation
Health
Understanding and predicting human population growth
Basic science question of what limits popualtion growth
Pink salmon graph
Spikes
In one ares over time pop can change a lot
HIV popualtion dynamics
CD4+ lymphocytes and hIV RNA copies
Up down middle to zero
Down spikes then down/mid then up the the end
Popualtion dynamics who
Malthus
An essay on the principle of population
-humans can only grow as fast as their environment ‘ can’t out grow it
General model for popualtion growth
N(t +1 sub)=f9Nt0
Differential equations
-time steps are infinitesimally small …calculus for continuous reproduction
Difference equations
-time is discrete steps
—iterated recursion equations
-episodic reproduction
Notations
-time is subscripted
-N starts at zero
D, B, E, I
N,nee of deaths
No,bee of born
Number of emigration
Number of immigration
Lambda
Is the finite rate of increase
>1, births exceed and pop grows
<1, deaths exceeding the pop and pop declines
Geometric growth model
Nt = N0 Lambdat
Continuos time …exponential growth model
R= intrinsic rate if increase
Differential question is dN/dt = rN
Simplified to Nt=N0 ert
r>0
What is bed about exponential growth models
Simple exponential growth is a bad model of reality ob]ver a long time
-other factors keep pop from exponentially blasting
-two kinds of factors ——
Density-dependent regulation : growth depends on N
-density independent reduction
Logistic growth models
Brakes on the exponential growth
-S curve
-dN/dt=rN (1-n/k)
N.K.r.t
Pop
Carrying ca-a city
Intrinsic rate of increase
Time
Sigmoid curves that are s are …
Only possible if u start at low numbers
Logistic growth model pro and cons
Pros
-intraspecific competition
-simple
-can consider multi species competitions
Cons
-too simple
-a;ways a gradual approach to K
—in reality, density dependence is likely to be non-linear
Possible ways to add more complexity or reality
-different forms of density dependence
-time lags
-incorporate species interactions
Population per capita growth rate is fastest when small unless
Allee effects
—social benefits
Age-structured pop cons
-exponential and logistic models of pop growth treat all individuals the same
-fecundity and survivorship are things
-life history stages
-
Age-structure pop growth
S and f carry with age
-summarized in life tables of age-specific rates
What is a life table
Data that summariz the life events that are statistically expected for the average individual of a specific age in a popualtion
Age of death
Age and timing of reproduction
For modeling, these are treated as constants
-usually consider females only
Types survivorship curves
lx is raw …gets curve down
Prop a lily of being Alive
Curve becomes straight line and is type 2
Type 1 is he curve over the middle. And type 3 is the curve under the middle
-log of lx
Type 1
Draw human life curve
Steep then flat until 40 then down steep then slow to the end
Senescence
Old age
Fecundity schedules
-age class denoted by subscript
-mx = number fo daughters born to a female of age x during the interval x to x+1
-shape of the max curve characteristic of species
-repod periods usually preceded by reoccurs accumulation phase
-fecundity - survivorship trade off cost of reproduction
Net reproductive rate
R0
-average expected number of daughters a female had in her lifetime =net reproductive rate
-is like lambda but in ti,e units of one generation rather than one time interval
Constrain and trade offs of fast growth rate and reproduction
More pre-reproduction time means more time to collect resources
Semelparous vs iteroparous organisms
Some…..Big Bang reproduction
Why does natural selection favours semelparity
Satiate seed predators
K strategy versus r strategy
-slaw f]growth
-longer generations ime
-large body size
More investment in somatic growth
Lower reproductive
Better competeive ability
-poor dispersal
More investment
-iterparity more likely
-shade tolerant plant
-fate set growth
Shorter generation time
-smaller body size
-more investment gonad
Higher reprod rate
Poor competing
Good at dispersal
-produce more but lighter seeds
-semelparity more likely
-shade intolerant seed dormancy
-born to run
Completion terms
-intraspecific
-interspecific
Scramble/exploitative
Contest/interference competition
Interspecific competition
Basic model : Lotka-Volterra equations
-simple outgrowth of logistic equation
-logistic already a haas braking term for intra-specific competition
-just add a second braking term for inter-specific competition
Lotka-voltetra models
Rewrite the logistic model with subscripts
dN/dt = rN (1-N/K - alphaN/K)
What is alpha in the l-v equation
Alpha ij = per-capita effect on i by j = competition coefficient
Possible outcome of l-v 4
Tow species stay stably coexist
Species 1 may always win
Species 2 may always win
Indiednity of winner may depend on starting Ns
Outcomes depend on values of K and Alpha
Foe species coexistence
Species cannot compete intensely
Or
Evolve sidiffreemces or occupy different elects of the niche
-paradox of the plankton
So many species coexisting
Paradox of the tropical rainforest
Either every species has a distinct niche
-something prevents competitive exclusion from driving species extinct
-that something is subject to intense study/debate
L-V models how were they tested
Protozoa
Gauze 30s
-saw both stable coexistence and competitive exclusion
Competition in lab v nature
In lab ….
Competitive exclusion is less likely to go to completion
-
Connell 61 experiment
Two barnacle species in the marine intertidal zone
-zone upper limits set by desiccation
-lower limit set by completion for space
Competition is asymmetrical
-either one will take the other over if removed
Paradox plankton resolved
-l-v models too simple
-most communities e not at competitive equilibrium
-other factors keep them below carrying capacity
Completion but of the entire community
Can impact commune composition and species richness
-decrease diversity
Different consumer interactions in the animal kingdom
Predation/carnivore
Grazing/herbivory
Parasitism/disease
Brood parasites
Birds lay eggs in the nest of another species to avoid parental care
-brood mimicry…evolve to resemble host egg
L-v models for predator-prey interaction
The w cycles
-prey foes really high then down
-predator only grows so ,icy before prey falls
Antagonistic coevolution
-red Queen hypothesis
-arms race
Life-dinner principal
Rabbit runs faster cause it’s life is at risk
Wolf just risks dinner
Competition in a community can be good for
Keeping pop in balance
-typically it decreases biodiversity but…Paige’s seas stars
Enemy release hypothesis
Invasive species become pests when they have no natural enemies
Competing ideas in community ecology of disease
Dilution effect- for disease that infect many hosts, host diversity can dilute the risk to humans or animals
Amplification effect- more hosts or vectors species can support larger pop of disease causing organisms
Symbiosis, mutualism
Lining together
Benefiting from the interaction both
Kinds of mutualism
Nutritional mutualism
-legumes and rhizobia:exchange fixed C for fixed N
Defensive mutualisms
-ants and plants …protection for food
Dispersal mutualism
-plants and animal seed dispersers….exchange food for dispersal
Mutualism in animal and human
Yao people in Mozambique harvest wild honey but can’t find bees nest easily
-honey guides
L-v but for mutualism
Minus turns to plus for the n play alpha n
L-v downfall in mutualism
Undergo silly solutions in which both populations undergo unbounded exponential growth
-limits
-strong intraspecific competition
-a third species
-diminishing returns to mutualism as the population grows
Invasional meltdown
-positive feedback between mutualisms tends to generate runaway popualtion growth
-what if two invasive species interact as mutualism
-invasional meltdown for the process by which two non-native species facilitate one another’s spread
Darwin’s orchid
Darwin predicated what the pollinator must look like
-reciprocal evolution
Bacterial endosymbiosis in aphids
Aphids feed on phloem sap that is rich in sugars but poor in essential amino acids
-they have intercellular bacteria that provide their hosts with essential amino acids
-buchnera are vertically transmitted, they are passed in aphid eggs from mothers to offspring
Endosymbiotic bacteria can…
Outsource functions to the host and lose genes that unnecessary
-have smaller genomes
Are mutualisms often highly specialized
Most aphids have their own species of buchnera bacteria
-but most mutualisms are Not tightly coevolved
-most are horizontally transmitted
-mutualisms are rarely one to one interactions, usually many to many interactions
-current hot areas of mutualism research include -networks and micro biomes
Characterizing microbial diversity in a host
Sequencing
-sequence highly conserved gene usually the bacterial 16S rRNA gene
-using DNA sequence data to identify microbes
—Frees us from having to culture microbes in order to study them
-
Micro biome research
-reflects diet of the individual
-impacts metabolism, immune system, and other traits
Fleshy fruit attract
Animal seed dispensers
Colonization of new habitats example
-post glacial colonization depends on plant and animal dispersal
—range shifts in response to climate change
-
Metapopulations
Populations of populations
-dispersal connects populations
-a meta population is a collection of spatially distinct populations that are connects vis dispersal
-we call each spatially distinct pop a patch
Metwpopoialtiojs struftus can allow pop persistence even when individual pop are doomed
-local populations can be reestablished by colonists form other populations after going extinct
-source sink dynamics
A sink in a newly colonized island
New prey grows to capacity
Predator reproduce quickly
-eat all prey
-they die too
Island level asructure is unstable
;locally unstable pop can be
Globally stable
Patch dynamics
-akin to popualtion dynamics but…
-instead do individuals in population, we track patch occupancy
-imagine the simple\\
Kevin’s patch occupancy model
Write it
Where is eqaulitbrium = 0
Metapopulation structure facilitates species persistence and coexistence
A single species ..,,tiger salamanders
-of predators and prey …imaginary island dynamics
-of competitors
A and B global coexistence
A outcomepetes B
A must go extinct occasionally or new patches must be created
-B must be better disperser than A
-so B must be fugitive, tramp, weedy, opportunistic, transient species
-completion-colonization trade off
General conclusion on species coexistence
Populations can be driven to extinction in several ways:
-stochasticity
-competitive exclusion
-alleles effects at low density
-BUT COUNTERED BY
—predation keeping competitive exclusion from going to completion
-non-equalibtium conditions, habitat patchiness, rescue by migration, variation in life-history strategy
Metacommunity
Is a set of local communities linked by the dispersal of one or more of their constituent species
What determines the number of species on an island
Colonization
Extinction
In-situation speciation
Macarthur and Wilson’s theory of island biography and draw graphs
Goes;-to predict the number of species on an island from the islands size and isolation
-ignored in-situ speciation
Col rate does down
Extinction rate goes up
-meet at equilibrium
-colinization is slower in farther islands
-extinction rate is faster in small islands
Species diversity on an island
Increase with ares . Decreases with isolation
Trophic levels
-primary producers-plants
-primary consumers -herbivores
-secondary consumers = predators cornivorews who eat herbivores
-tertiary consumers-carnivores who eat secondary consumers
-decomposers = eat dead organic matter
Indirect effects
-one species alters the effect that another species has on a . Third
-explotative or scramble competition I\if the contested resource is a species
Draw it
Trophic cascade
Interactions between two Trophic levels cascade to a third Trophic level
-secondary easts primary who eats primary producer
-primary producers and the secondary consumer have indirect affect
Trophic cascades and the green earth
The earth is green because the secondary carnivores keep the primary consumers in check
Top down versus bottom up control
Top down-abundance kept low because of predation ….test by predator removal
Bottom up control-andundacae kept low because of resource limitation ….test by resource addition
three facts about Trophic cascades
-indirect can be just as strong as direct
-outcomes not fundamentally predictable, depends on interaction strengths
-experiments needed, perhaps long-term
Special difficulties of herbivory
-easy to be a carnivore:animal tissue easy to convert into animal tissues
-plant tissue is hard to convert into an animal tissue
-cellulose and lignin tough and indigestible without microbial symbionts
-coevolution race between herbivores and chemical defended
Generalist vs specialist
Eat all and general
Specific adaptations to eat otherwise poisonous food
Vertebrate herbivores
Many inspects complete development on a single often well-defended plant, they must overcome plant defences
-vertebrate grazers often eat some plant tissues and the mice to another plant
-vertebrate herbivores often select ,iced diets congaing foods processed by different detoxifying pathways
-some detoxify by microbes in hfermentaion chambers
How is the climate changing
Not just temperatures
Circulation patterns are changing
Extreme weather events are becoming more frequent
-local climate changes are affecting organisms
Acclimatization example
Early or gradual can reduce impacts
Porcelain crabs acclimated to cold temperatures function better at colder temperatures
-but acclimatization to warn temperature siceasee only mini,ally
Wilson said about extinction
Can’t be undone
Least predictable consequences
Conextinctions
Dependent species
-co-extinction
-mutualism and host-parasite interactions …depended on how specialized
Conclusion to climate change
The best way is to reduce carbon emissions
