MTEL SUBSET III

  • Population ecology : the study of groups within a species and how they live together in one geographic area

    • Population : a group of individuals of one species who interact regularly 

    • Population density : the concentration of individuals within a species in a specific place

      • Population density changes due to a number of factors : 

        • Increases when individuals are born or immigrate 

        • Decreases when individuals die or emigrate

    • Dispersion : the geographic arrangement of the individuals within the population 

    • Population growth : a population increase over a given period 

      • Several factors drive population growth : 

        • Fecundity : how many offspring an individual can have in a lifetime 

          • EX : mosquitoes can have 2,000 offspring in their 2 week lifetime, rhinos can have about 5 in 40 years 

    • Limiting factors : anything that constrains a population’s size or stops it from growing

      • EX : food, temperature, mates, space 

      • Density-dependent limiting factors : limiting factors dependent on population size

        • Inhibit growth because of the environmental stress caused by a population size 

        • EX : disease, access to resources, predator population

      • Density-independent limiting factors  : limiting factors that are not dependent on population size 

        • EX : catastrophe, nature (volcanic eruption, thunderstorm, temperature)

    • Carrying capacity : the number of individuals that a habitat can sustain with the resources that it has available 

    • Exponential growth : a population grows at a rate proportional to the size of the population 

    • Logistic growth : a population is limited to the carrying capacity of its habitat

  • Community ecology : the study of different organisms living together and figuring out how they influence each other 

    • Competition : when organisms compete for limited resources like food, territory, and mates

    • Community : a group or association of populations two or more different species occupying the same geographical area at the same time 

    • Types of competition : 

      • Competitive exclusion : two species competing for the same resources, one is more successful, and eliminates the other

        • Competitive exclusion principle : two species competing for the same resources can not coexist in the same habitat

    • Ecological niche : the sum of all resources, both biotic and abiotic, that a species uses in its environment

    • Fundamental niche : an ideal, allows a species to avoid competitive exclusion

    • Realized niche : the set of conditions actually used by given animal (pop, species), after interactions with other species (predation and especially competition) have been taken into account.

    • Resource partitioning : when similar species settle into separate niches that let them coexist 

    • Character displacement : an evolutionary change that occurs when two similar species inhabit the same environment

    • Mutualism : both species benefit

      • Obligate mutualism : one of the species would not be able to survive without the other

    • Commensalism : one species benefits, one isn’t hurt or helped

    • Co-evolution : the process by which interactions between two species affect the evolutionary development of both 

    • Predation : one type of organism kills another for its energy

      • Types of predation : 

        • Herbivory : an organism eats plants or algae to capture their energy 

        • Parasitism : organisms derive energy from the host, usually harming it and sometimes killing it in the process

    • Hunting and feeding adaptations : sense of smell, teeth, sharp eyes, talons, venom

    • Detection adaptations : camouflage (cryptic coloration)

    • Capturing adaptations : speed, herds

    • Handling adaptations : rose’s thorns, sap, tobacco plant’s nicotine, 

      • Aposematic (warning) coloration : coloration that distinguishes an organism is toxic 

      • Mullerian mimicry : the more unpalatable prey there are that use the same color patterns, the more likely predators are to avoid all prey with that appearance in general

      • Batesian mimicry : where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both

  • Ecosystem ecology : the study of how all living and non-living things interact within an entire ecosystem

    • Ecological succession : how the makeup of a community changes over time, starting from right after the disturbance

      • Primary succession : when organisms populate an area for the first time (no competition, mostly talking about plants)

        • Pioneer species : first inhabitants after the disturbance 

        • Primary succession takes a very long time (hundreds, maybe thousands of years)

      • Secondary succession : the ecological succession that occurs after primary succession

    • Climax community : a predictable assemblage of species that would remain stable until the next big disturbance 

    • Stochasticity : randomness, prevents us from ever knowing exactly what a community is going to look like 100 years after a disturbance 

    • An ecosystem is in later successional stages if it has high biodiversity 

      • Biodiversity can be high only if there are tons of little niches for all those species to fit into 

      • The only way there could be that many niches is if, instead of a single community, an ecosystem ismade up of thousands of tiny communities 

        • A mosaic of habitats, where specific communities of different organisms lived

    • Intermediate disturbance hypothesis : hypothesizes that intermediate disturbances are ideal

      • Intermediate disturbances are good for ecosystems, creates biodiversity and mosaics 

    • Ecosystem : a collection of living and nonliving things interacting in a specific place 

      • Organisms, weather patterns, geology 

    • Ecosystem ecology looks at how energy and materials come into an ecosystem, move around, and leave the ecosystem 

    • An ecosystem can be measured by : 

      • Biomass : the total weight of living things in the ecosystem

      • Productivity : how much stuff if produced and how quickly stuff grows back, how good the ecosystem is at retaining stuff 

    • Organisms in an ecosystem organize themselves into a trophic structure 

      • Each organism situates itself in a certain place in a food chain

      • Autotrophs use the sun’s energy and through photosynthesis, make chemical energy 

        • Autotrophs are the foundation upon which all other organisms in the system get their energy and nutrients

      • Primary producers : autotrophs that synthesize energy from the sun into chemical energy 

      • Primary consumers : herbivores, the first heterotrophs to obtain the energy from primary producers (autotrophs) 

      • Secondary consumers : carnivores, consume the herbivores 

      • Tertiary consumers : carnivores that eat other carnivores 

      • Detritivores : decompose all the dead animal and plant matter, as well as animal waste (poop!)

    • Food web : takes into consideration that sometimes organisms are obtaining energy from different levels within the trophic structure 

    • Each trophic level only absorbs 10% of the energy of the level below 

      • Only 10% of energy is passed up each level

    • Bioaccumulation : the gradual accumulation of substances, such as pesticides or other chemicals, in an organism, occurs when an organism absorbs a substance faster than it can be lost or eliminated by catabolism and excretion

      • As we move up the chain, concentrations get much higher at the food chain