Unit 2 test flashcards

Unit 2 (2/5-xxx)
Environmental Bio 🎉

___(I. Mitchell)

Notes

• Population ecology: how populations interact with their environment

  • Includes birth, death rates, and immigration and emigration

  • How do population sizes change through time 

• Population: # of organisms of the same species that live in a particular area at the same time, with the ability to interbreed

• How populations grow

  • 3 common patterns of growth (show their potential if there are no limitations (their unlimited ability)

    • Arithmetic

      • Growth isn't constant

      • Not realistic long-term

      • The growth increases constantly over time; the same # individuals are added at each generation.

    • Exponential (J-shaped growth)

      • Growth accelerates with each generation

      • Not realistic long-term

      • Growth whose rate becomes ever more rapid in proportion to the growing total number or size often when resources are available in a new environment 

  • Both are unrealistic because of the presence of diseases, predators, etc.. ( THEY DO NOT FACTOR IN ENVIRONMENTAL CHANGE AND LIMITATIONS)

• Population growth rate

  • (percentage of population that is new divided by time)

    • % change per year

  • Doubling time: the length of time required for the population to double in size

    • Quick estimate=(70/population growth rate)

    • About 10% accurate

    • Steps to double time: 

      • take 70 ➗the percentage 

      • Add that to the current year.

  • How to calculate the net number (how much does it grow after you take out the losses)

    • (net number of new individuals)

      • growth rate= (Birth + immigration) - (Death + Emigration)

        • Birth

          • Reproduction

        • Death

          • Mortality

        • Immigration

          • # entering 

        • Emigration

          • # leaving 

• Exponential Growth Formula: (take from slideshows) 

• Population Growth rates vary by species

  • The smaller the organism, m the faster they grow, and the smaller their growth rate

• Growth with limits (takes the “s” shaped curve)

  • Populations cannot grow forever

    • There are limits to growth

    • Carrying capacity: the maximum number of organisms the environment can support

      • Competition reduces the reproduction rate

      • Range of tolerance also affects reproduction rates

    • Environmental resistance: Factors affecting population growth

      • As resources deplete, birth rates decrease, and deaths increase  

  • A more realistic pattern of growth

    • Logistic growth: occurs when resources are limited,d thereby setting a maximum number an environment can support 

      • Fast when the  population is small, slower as the population is large

  • Range of tolerance: range between minimum and maximum values for survival

    • Temp

    • Space

    • Chemical

    • (often Abiotic)

• Habit and Niche

  • The range of tolerance for various factors determines…:

    • Habitat: the complex environment organism depends on for survival

      • The location you can describe

      • Temperature, humidity, living elements like food and nutrients

    • Ecological Niche: the role an organism fills and performs in the ecosystem

      • What it does

      • Various activities the organism performs and how it does it

      • The complex includes all interactions

        • Biotic and abiotic in the ecosystem

    • Trick:

      • Species: its name

      • Habitat: its address

      • Niche: its career or how it makes a living 

• Survivorship: the probability of an organism dying during a particular interval

  • Species survival varies widely 

    • Type 1: most die old

    • Type 2: Young and old people die equally

    • Type3: most die young

• Can organize exceed their carrying capacity

• 
  

  • What does it mean

    • Organisms can temporarily exceed their carrying capacity because, many times,s they produce more offspring than the environment can support

    • Who lives and who dies is based on who can get the most resources 

• EVOLUTION:

  • Inherited changes in a population over time (individuals don't evolve; the population does)

    • Genetic change in a population

    • Across generations (the offspring, reproduction)

    • Descent with modification (Charles Darwin)

    • Is the major unifying concept in biology

    • Population evolve in response to ecological pressures; an understanding of evolution and ecology helps understand why organisms are the way they are 

      • Ecological pressure

  • Individuals do not evolve

  • There are different ways population evolve

    • Adaptive evolution: species become better suited to their environment over time (natural selection)

      • The only adaptive evolution

    • Non-adaptive evolution: species do not become better suited to their environment

      • Artificial selection

      • Genetic drift

      • Other mechanism 

  • All evolution starts with mutation, the ultimate source of natural variations.

    • Mutations: random changes in DNA

• Artificial selection: the  process by which humans use animal and plant breeding to selectively develop particular traits by choosing which animal or plant makes and females will sexually reproduce and have offspring together

  • Form of differential reproduction: when some individuals in a population have more offspring than others due to their traits

  • Solely based on which traits humans deem desirable 

    • These traits make them less suited to live on their own-adaptive evolution

    • Non-random evolution (people influence)

• Natural selection: Certain members of a population may be better suited to their environment; therefore, they are more likely to survive and produce offspring that inherit the beneficial traits

  • Nature must also be able to influence differential reproduction 

    • It is also of differential reproduction

  • Fitness Biological : biological in terms of evolution

    • The ability of organisms to produce viable offspring

      • Measured inability to have grand offspring

    • Differential reproduction is influenced by fitness

    • EX: Mules cannot produce offspring, and so has no Fitness

    • Fitness is influenced by the ability to survive and reproduce in the environment

  • Adaptations: Inherited structures, functions, and behavior, that increase the ability to survive and reproduce in the environment (traits)

    • Most Fit leave more offspring; their adaptation becomes more common

    • Less fit have fewer offspring; their adaptation becomes less common

    • The population changes over time 

  • Natural selection steps:

    • 1. There is variation in the trait within the population

    • 2. The trait is determined by genetics and hence heritable

      • DNA encodes for that trait

    • 3. Individuals with certain variants of the trait have higher fitness

    • 4. There is competition for survival and reproduction between individuals within a population

  • Disclaimer: Survival and reproduction of the fittest 

    • Those that are better able to compete within this struggle for existence = have higher survival and pass on to offspring rates

      • Adaptive evolution

      • Non-random evolution (environmental influence 

• EX: Darwin’s fished

  • Galapagos Island

  • 14 species occupy a variety of different niches

  • Adaptive radiation: when several species evolve from a single ancestral species to occupy new niches

    • Evolution is not always slow and gradual 

    • The trait is only as beneficial as its current environment

• Three types of natural selection

  • Directional: one end of the range of variation favored

  • Stabilizing: middle range of variation favored

  • Disruptive: both extreme ends of the variation are favored over the average traits. 

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• Genetic drift is completely random.

  • A change in the frequency of an inherited trait that is caused by a chance event 

    • Non-adaptive evolution (not caused by fitness)

      • Do not become more suited for their environment

    • Random evolution (not caused by adaptive traits)

• Founder effect: type of genetic drift 

  • A change in the frequency of an inherited trait that is caused by a small subset of the population

• EVOLUTION OF SPECIES

  • Population may change or split into different species since they become isolated from each other and follow different evolutionary pathways. 

• Evolution is not linear.

  • Linear progression andreplacementss false 

  • Involved diversification

    • Branch points

• Productive isolation: members of one species do not interbreed with members of other species ( breeding barriers)

  • Isolation keeps groups separate while they may be evolving into separate species

  • Isolation keeps groups separated after they have evolved into separate species 

    • A hybrid between two species are often sterile, like the mule

• Types of reproductive isolation

  • Geographic isolatioSeparateded by space

    • Keeping to their known environments

  • Temporal isolation

    • Time 

    • Matting at different times

  • Behavioral isolation

    • Courtships

    • singing, dancing, body posture 

    • Every species has a titsown courtship

    • Only recognize the song of the same species

  • Structural isolation

    • Different structures for different species

• Human effects on evolution and extinction

  • Humans affect evolution in ways 

    • Artificial selection

    • Humans cause a lot of extinction

  • The flipside of evolution and speciation is extinction

    • Dying out or extermination of a species

Note: wasnt feeling good on the 14th and 17th, notes are incomplete

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• Mass extinction: 

  • In a short period, planet-wide

• Background Extinction:

  • The average rate of extinction between mass extinction events; is always occurring. 

• Species that cannot evolve and adapt to a changinenvironmentnt are designed to go extinct. 

• We are possibly in a 6th major extinction event, which humans may cause 

• Pre- agreiculutral Period

  • Begin 100,000 years

• Demographic Transition Model

  • Pretransiuiona

    • Birth and death =high rate

    • Limited resources,

    • Deaseae spread fast

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• The more developed nations have lower birthrates

  • Lower birth rates correlate to higher GDP

  • Age structure

    • Determined by survuvirship and age-specific bith rate

  • Age structure pyramid

    • Graphically display age structure

    • Shape indicates rate of population growth

• Population of 8.1 billion people on the planet 

  • 9 million in 15 years

• Rapid population growth in the last 250

  • Source of many of our environmental issues

  • Rate of consumption

    • Everyone doesn't use the same amount of resocers

    • Everyone doesn't has the same access to resources

    • Varies by country and their national economy tremendously

• Human population growth is exponential

• Ecological footprint: area of land needed to supply resources consumed by people 

  • Includes: cropland, grazing, forests, fisheries, carbon footprint, but-up land, water, and waste disposal

• Suitability vs caring capacity

  • Caring capacity is the size ofthe  population environment that can support 

  • As population approach

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• Human resources use

  • Biocapacity: area and quality of land available to supply resources

  • Population whose ecological footprint exceeds their capacity must have good imported

    • Ecological debtors

  • Populations whose biocapacity exceeds their ecological footprint may export goods: ecological creditors

  • Wealthy nations rely on the resources of the creditors 

Community Ecology:

• Definition: examines how organisms in a community interact with each other and their environment

  • The study of the organization and functioning…

• Community: a group or association of population of two or more different species occupying the same geographical area and in a particle time 

• In a community, multiple species coexist and interact (biotic interactions)

  • Six categories of how they interact with each other

    • Competition (Biological)

      • 2 or more groups in question must use the same resource

      • The resource must be in short supply

      • The fitness (biological fitness)  of each group is reduced when they occur together

        • No matter what both parties lose fitnessbecuse when they spend time competing, it's not spent on reproducing resting, or getting food ( competing is a limiting factor when it comes to fitness)

      • This causes more energy and time to be spent gaining fewer resources than they normally would (this is a disadvantage to all involved)

      • Any 2 species (even plants) can compete 

      • ALL OF THE TYPES OF COMPETITION CAN BE STACKED ( A SITUATION CAN HAVE MORE THAN ONE TYPE)

      • Exploitative competition: competitors consume or use the same limiting resource 

        • But they are NOT FIGHTING FOR IT

        • NO AGGRESSION

      • Interference competition: competitors deny each other access to the limiting resources

        • Active competition

      • Interspecific competition: competition between two different species 

      • Intraspecific competition: competition between members of the same species

      • Stackables (the ones we will focus on in this class) : 

        • Interspefic Explotiative

        • Intraspecific Interference

        • Intrasecic Explotitative

        • Interspecific Interference

      • Competicve exculasion principle

        • 2 species that directly compete for resources cannot coexist 

          • Can drive one or the other into extinction

      • No two species can coexist using the same resources

      • Ecological Niche: the role an organism fills within its habitat

        • Fundamental niche: complete range of areas in which an organism could exist (wide range)

        • Realized niche: range in which an organism exists due to competition (small range)d

          • Analogy: 

            • Fundamental niche-any career in this world (what do you want to be when you grow up)

            • Realized niche-what you grow up to do, not everyone can be the president because of competition, so they settle

              • Cant be president but can be vice president 

      • Niche differentiation: a smaller subset of realized niche. Going to different subsets of the resource

Species survive by dividing and sharing resources

• Herbivory

  • Adapted to feed on plant material

    • Specilized digestive systems

  • Coevolution of herbivores and plants

    • Plants evolve ani0herbivory chemicals and mechanical defenses

    • Herbivores evolve the ability to detoxify plant chemicals 

• Perdition

• Parasitism

• Mutualism

• Commensalism 

• Biotic Interactions slide

  • (-) they are receiving harm from the other individual 

    • A is receiving harm from B

  • (+) they are receiving benefits from the other

    • A is receiving benefit form b

  • (0) no consequence of significant from the other

    • A does not affect B or B does not affect A

• Coevolution: when two or more species reciprocally affect each other’s evolution through the process of natural selection

  • Species a and B

    • A eats b

    • A is going to evolve to be a better predator to eat b

    • B is not helpes, b can evolve to  be harder to catch

    • Influences a to be an even better predator 

  • (see the cycle ;) )