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Ecology Pt 2 - Coggle Diagram

- - - - Population growth that levels off as population size approaches carrying capacity.
      - dN/dt = rN((K-N)/K)
      - The rate of population growth decreases as population size approaches the carrying capacity of the environment
      - real life
        
        If food becomes limiting for a population, for instance, reproduction will decline eventually, but females may use their energy reserves to continue reproducing for a short time. This may cause the population to overshoot its carrying capacity temporarily
        
        water fleas
        
        there is often a delay before the negative effects of an increasing population are realized
        
        Populations in nature rarely match the predictions of the logistic model as closely as do some laboratory populations
  - - - change in pop = births + immigration -deaths - emigration
      - calculations
        
        ⛛ N/ ⛛ t = B - D
        
        evaluating population growth
        
        ⛛ N/ ⛛ t = R
        
        N represents population size
        t represents time
        B for Births
        D for deaths
        R represents the difference between the number of births and the number of deaths
        
        (r ⛛ t): The per capita change in population size represents the contribution that an average member of the population makes to the number of individuals added to or subtracted from the population during the time interval
        
        R = (r ⛛ t)N
        
        ⛛ N/ ⛛ t = (r ⛛ t)N
        
        ecologists prefer to use differential calculus to express population growth as a rate of change at each instant in time
        
        dN/dt = rN
        
        r represents the per capita change in population size that occurs at each instant in time
        
        dN/dt represents the rate at which the population is increasing in size at each moment in time
    - - dN/dt = rN
      - intrinsic rate of increase
        
        (r) In population models, the per capita rate at which an exponentially growing population increases in size at each instant in time.
      - per capita rate of population growth is constant (and equals r ), more new individuals are added per unit of time when the population is large than when it is small
      - population of elephants in Kruger National Park, South Africa, grew exponentially for approximately after they were first protected from hunting
  - - - calculations
        
        calculation by counting individuals in a random 100x100 m plot sampling plots in a homogeneous habitat
        
        x/n=s/N
        
        mark-recapture method
        A sampling technique used to estimate the size of animal populations.
      - subtractions
        
        emigration
        
        death
      - additions
        
        birth
        
        immigration
        
        Ex: pop of Hector's dolphins in New Zealand
    - - Life tables: summary of the age-specific survival and reproductive rates of individuals in a population
        
        follow the fate of a cohort, a group of individuals of the same age
      - Survivorship curves: plot of the number of members of a cohort that are still alive at each age; one way to represent age-specific mortality.
        
        begins with a cohort of a convenient size, for example. 1k individuals
        
        Type 1
        
        flat at the start, reflecting low death rates during early and middle life, and then drops steeply as death rates increase among older age-groups
        
        large mammals
        
        Type 2
        
        curves are intermediate, with a constant death rate over the organism’s life span
        
        Belding’s ground squirrels and some other rodents, many invertebrates, lizards, and annual plants.
        
        Type 3
        
        curve drops sharply at the start, reflecting very high death rates for the young, but flattens out as death rates decline for those few individuals that survive the early period of die-off
        
        long-lived plants, many fishes, and most marine invertebrates
        
        associated with organisms that produce very large numbers of offspring but provide little or no care
        
        complex patterns
        
        crabs: may show a “stair-stepped” curve, with brief periods of increased mortality during molts, followed by periods of lower mortality when their protective exoskeleton is hard
        
        birds: mortality is often high among the youngest individuals (as in a Type III curve) but fairly constant among adults (as in a Type II curve
      - Reproductive rates
        
        demographers view populations in terms of females giving rise to new females
        
        Reproductive output for sexual organisms such as birds and mammals is typically measured as the average number of female offspring produced by the females in a given age-group
    - - uniform
        
        king penguins and other birds nesting on small islands spreading due to territotial behavior of neighnors
        
        antagonistic social interactions, such as territoriality
      - clumped
        
        starfish grouped together where food is abundant
      - random
        
        dandelions in a field
  - - - semelparity
        Reproduction in which an organism produces all of its offspring in a single event; also called big-bang reproduction.
        
        salmon
      - iteroparity
        Reproduction in which adults produce offspring over many years; also called repeated reproduction.
        
        female loggerhead turtle
    - - between the number of offspring and the amount of resources a parent can devote to each offspring
      - Plants and animals whose young have a low change of survival often produce many small offspring
        
        dandelions
      - Animals that suffer high predation rates tend to produce many offspring
        
        mice, quail
      - extra investment on the part of the parent greatly increases the offspring’s chances of survival
        
        Brazil nut and walnut trees produce large seeds packed with nutrients that help the seedlings become established
        
        Primates generally bear only one or two offspring at a time; parental care and an extended period of learning in the first several years of life are very important to offspring fitness
      - K-selection
        Selection for life history traits that are sensitive to population density.
        
        stronger competition among individuals in high density pops
      - r-selection
        Selection for life history traits that maximize reproductive success in uncrowded environments.
        
        often found in disturbed habitats that are being recolonized
        
        individuals face little competition
        
        weeds
  - - - Age structure
        
        The relative number of individuals of each age in a population.
        
        The age structure for the United States is relatively even until the older, postreproductive ages
      - infant mortality and life expectancy
        
        Infant mortality, the number of infant deaths per 1k live births, and life expectancy at birth, the predicted average length of life at birth
        
        social upheaval, decaying infrastructure, and infectious diseases such as AIDS and tuberculosis are reducing life expectancy
      - regional patterns
        
        0 pop growth = high birth rate - high death rate or 0 pop growth = low birth rate - low death rate
        
        demographic transition: In a stable population, a shift from high birth and death rates to low birth and death rates.
      - more than 7.9 billion people increasing by about 75 miilion each year
    - - estimates
        
        Carrying capacity is difficult to estimate, and scientists use different methods to produce their estimates
        
        The first known estimate, 13.4 billion people, was made in 1679 by Anton van Leeuwenhoek
      - limits
        
        ecological footprint: the aggregate land and water area required by a person, city, or nation to produce all of the resources it consumes and to absorb all of the waste it generates.
        
        calculation yields an allotment of 1.7 global hectacre per person—the benchmark for comparing actual ecological footprints
        
        typical ecological footprint for a person in the United States is 8 gha
  - - - density independent: referring to any characteristic that is not affected by population density
        
        death rate of fescue grass
      - density dependent: referring to any characteristic that varies with population density.
        
        birth rate of fescue grass
    - - resource competition
        
        higher transmission in citties than rural areas
      - disease
      - terrirtoriality
        
        chemical urine marking in cheetahs
      - toxic waste
        
        ethanol production of yeast
      - intrinsic factors
        
        reproductive rate in white footed mice
    - - stability and fluctuation
        
        Populations of large mammals were once thought to remain relatively stable, but long-term studies have challenged that idea
        
        Harsh weather, particularly cold winters with heavy snowfall, can weaken moose and reduce food availability, decreasing the population size
        
        When moose numbers are low and the weather is mild, food is readily available and the population grows quickly
        
        lake not freezing limiting the emigration and immigration for moose and wolves
      - cycles
        
        many populations fluctuate at unpredictable intervals, others undergo regular boom-and-bust cycles
        
        10-year cycling of snowshoe hares
      - immigration, emigration, and metapopulations
        
        metapopulation: group of spatially separated populations of one species that interact through immigration and emigration.
        
        Glanville fritillary
        
        When a population becomes crowded and resource competition increases, emigration often increases
- - - - three broad categories of ecological interactions: competition -/- , exploitation +/- , and positive interactions +/+ or +/0
    - - exclusion
        
        The concept that when populations of two similar species compete for the same limited resources, one population will use the resources more efficiently and have a reproductive advantage that will eventually lead to the elimination of the other population.
      - eco niches: The sum of a species’ use of the biotic and abiotic resources in its environment.
        
        resource partitioning: division of environmental resources by coexisting species such that the niche of each species differs by one or more significant factors from the niches of all coexisting species.
        
        Seven species of Anolis lizards live in close proximity, and all feed on insects and other small arthropods. However, competition for food is reduced because each lizard species has a different preferred perch, thus occupying a distinct niche.
        
        nocturnal common spiny mouse and diurnal golden spiny mouse sharing resources at different times of the day
        
        fundamental niche which is the niche potentially occupied by that species
        
        realized niche the portion of its fundamental niche that it actually occupies
      - character displacement: The tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.
        
        Galápagos finches Geospiza fuliginosa and Geospiza fortis: Beak depths in these species are similar in allopatric populations but have diverged considerably in sympatric populations
    - - predation
        
        Predators that pursue their prey are generally fast and agile, whereas those that lie in ambush are often disguised in their environments
        
        defensive adaptations
        
        aposematic coloration: warning coloration
        
        poison dart frog
        
        Cryptic coloration: camouflage,
        
        canyon tree frog
        
        Batesian mimicry: mimic behavior
        
        hawkmoth mimicking venomous parrot snake
        
        Mullerian mimicry: mimic looks
        
        cuckoo bee and yellow jacket
        
        Mechanical: quills, thorns
        
        porcupine
        
        chemical: venom or odorous spray
        
        skunk
      - Herbivory interaction in which an herbivore eats parts of a plant or alga, thereby harming it but usually not killing it
      - parasitism: parasite derives its nourishment from another organism, its host, which is harmed in the process
        
        endoparasite
        
        tapeworm
        
        ectoparasite
        
        ticks, lice
    - - Mutualism: positive-positive interaction that benefits individuals of both of the interacting species
        
        acacia tree has protection from ants and the ants use thorn to house eggs
      - commensalism: positive-neutral interaction that benefits the individuals of one of the interacting species but neither harms nor helps the individuals of the other species
        
        cattle egrets feed on insects flushed out of the grass by grazing bison, cattle, horses, and other herbivores
  - - - When a forest fire burns the lodgepole pine trees, the cones open and the seeds are released. The new generation of lodgepole pines thrive on nutrients released from the burned trees and in the sunlight that is no longer blocked by taller trees.
    - - primary succession: type of ecological succession that occurs in an area where there were originally no organisms present and where soil has not yet formed
        
        volcanic islands or revealed land by moving glaciers
        
        Stages: pioneer > dryas > spruce >alder
      - secondary succession: recolonization of an area after a major disturbance has removed most but not all of the organisms in a community
        
        natural disasters
    - - disturbance by human activities is often severe, it reduces species diversity in many communities
        
        trawling
  - - - white band disease on coral reefs
        
        :arrow_upper_right:
        
        dead coral overgrown by algea
        
        :arrow_upper_right:
        
        Surgeonfish feed on algae dominate the fish community
      - sudden oak death
        
        :arrow_down:
        
        killed more than a million oaks and other trees
        
        :arrow_down:
        
        loss of the oaks has led to the decreased abundance of at least five bird species
    - - zoonotic pathogens: disease-causing agent that is transmitted to humans from other animals.
        
        causes three-quarters of emerging human diseases and many of the most devastating established diseases
        
        transferred to humans from other animals via an intermediate species called a vector
        
        Lyme disease, Zika virus, Ebola hemorrhagic fever, monkeypox, and covid-19
        
        MERS, which originated from the transfer of the coronavirus from camels to humans :
        
        SARS, which originated from the transfer of the coronavirus from bats to civet cats to humans
      - Human activities, such as climate change and the destruction of natural habitat for urban or agricultural development, increase the risk of zoonotic disease by allowing animal carriers of disease to move into new geographic regions and by increasing the contact people have with wild animals
  - - - evapotranspiration: total evaporation of water from an ecosystem, including water transpired by plants and evaporated from a landscape, usually measured in millimeters and estimated for a year
        
        function of solar radiation, temperature, and water availability, is much higher in hot areas with abundant rainfall than in areas with low temperatures or low precipitation
      - Two key factors that can affect latitudinal gradients of species richness are evolutionary history and climate
      - life was generally more abundant and diverse in the tropics than in other parts of the globe
    - - species area curve: The biodiversity pattern that shows that the larger the geographic area of a community is, the more species it has
        
        in the Sunda Islands of Malaysia, the number of bird species increased with island size
    - - the number of species on an island represents a balance between the immigration of new species to the island and the extinction of species already there
      - immigration rate decreases as the number of species on the island gets larger, while the extinction rate increases
      - mangrove island
  - - - species richness: The number of species in a biological community.
      - relative abundance: The proportional abundance of different species in a community.
    - - Higher-diversity communities are often more resistant to introduced species
      - most diverse plots consistently produced more biomass
      - Higher-diversity communities generally are more productive and are better able to withstand and recover from environmental stresses
    - - food chain
        
        trophic level: The position an organism occupies in a food chain.
      - food web: group of food chains linked together
      - limits
        
        energetic hypothesis: concept that the length of a food chain is limited by the inefficiency of energy transfer along the chain.
        
        carnivores tend to be larger at higher trophic levels
    - - Foundation species have strong effects on their communities as a result of their large size or high abundance
        
        trees
      - keystone species: species that is not necessarily abundant in a community yet exerts strong control on community structure by the nature of its ecological role or niche.
        
        a sea star in maintaining the diversity of an intertidal community
      - ecosystem engineers: organism that influences community structure by causing physical changes in the environment.
        
        beaver
    - - bottom up
        
        the abundance of organisms at each trophic level is limited by nutrient supply or the availability of food at lower trophic levels
        
        lack of deer control pop of wolves
      - top down
        
        the abundance of organisms at each trophic level is controlled by the abundance of consumers at higher trophic levels
        
        wolf predation on deer impact deer pop