APES Unit 3 PDF

Order of Life: populations, community, ecosystems, biomes, biosphere Population Ecology: the study of factors that cause populations to increase/decrease in size ○ Conservation effect, monitor endangered species, pest control, setting of hunting limits Population Characteristics...

Order of Life: populations, community, ecosystems, biomes, biosphere Population Ecology: the study of factors that cause populations to increase/decrease in size ○ Conservation effect, monitor endangered species, pest control, setting of hunting limits Population Characteristics to find increase/decrease ○ Population Density: number of individuals per unit area or volume - aquatic Helps identify if a species is rare or abundant Can also help predict overstripping of food supply (ex. Set fishing limits) ○ Population Size : total number of individuals in a population/of one species Affected my death rate, offspring produced rate/amount, density independent and dependent factors ○ Distribution Patterns: random (trees), uniform (nests/territorial), clumped (herds) ○ Sex Ratio: many different species have diff ratios of male: female Effects future population or generation/amount of offspring ○ Age Structure: scale of amount if individuals in each age range Shows growth potential - predicts population increase or decrease Density Independent: same effect on survival and reproduction but regardless of population size (ex. tornado) Density Dependent:factors that influence the probability of survival and reproduction but relating to the population size (ex. Limited food) ○ Limiting Factor: resource population cannot live without; relationship dependent for population size Population Growth Model:math equations to predict the population size ○ Population Growth Rate: number of offspring an individual can produce minus death ○ Intrinsic Growth Rate: particular max potential growth, denoted as r Under ideal conditions of unlimited resources meaning that the population growth rate, with real limited resources, will be lower than r (less offspring and more deaths) Exponential Growth: how rapidly a current population increases in size w unlimited resources Nt = Noert ○ Under ideal circumstances, the future size of a population (Nt) depends on the current population size (No), intrinsic growth rate (r) and amount of time (t) ○ J shaped curve represents the change in a growing population over time Logistical Growth; initially exponential → slows at it approaches carrying capacity (k)  ○ S-curved shape and accounts for density dependent factors to predict population growth since independent factors are unpredictable ○ Change often cause overshoots and diebacks ○ Graph slows at ½ towards caring capacity K-Selected Species: low intrinsic rate, causing population to increase slowly until carrying capacity (k), and stays/does not fluctuate much at carrying capacity ○ Long life span, long time to reproductive maturity, few reproductive events, few and large offspring, substantial parental care, slow population growth rate, density dependent factors regulating population size, population dynamics are stable and near carrying capacity ○ If endangered, since rare population size fluctuations, cannot respond quickly in efforts to save itself from extinction R-Selected Species: high intrinsic growth rate, population size rarely at carrying capacity ○ Commonly experiencing overshots and major diebacks ○ high intrinsic growth rate which allows easily/oftenly passing carrying capacity ○ Short life span, short time to reproductive maturity, many reproductive events, many and small offspring, little to no parental care, fast population growth rate, density independent factors regulate population size, highly variable population fluctuations ○ maximizes how many offspring survive by producing a great number of young Survivorship Curve: species have distinct pattern of survival over the life span of individuals ○ Type I Survivorship Curve: high survival throughout life span, but die in big numbers at an old age - K Selected, (ex. Elephants, human, whales) ○ Type II Survivorship Curve: constant decline in life span (ex. Squirrels, corals) ○ Type III Survivorship Curve: low survivorship early in life, few make it to adulthood - R Selected, (ex. mosquitoes , dandelions) Metapopulations: a group spatially distinct population connected by occasional movements of individuals ○ Each population has their on dynamics based on local abiotic conditions and prey availabilities ○ Corridors: strips of natural habitat that connect populations Connectedness is important for persistence as many smaller populations have a smaller survival chances due to lack of genetic variation (adaptation to living condition changes) Inbreeding Depression: blood relatives mate and reproduce impaired offspring unable to survive and reproduce Also more vulnerable to catastrophes (ex. Harsh winters) Immigrants from bigger populations help smaller populations ○ Metapopulations fight better from diseases as scattered in clumps  ○ Due to human activity, metapopulations are becoming more common ○ Ex. LA sprawl and urbanization troubles Mountain Lion Populations Community Ecology: study of interactions among species Symbiotic Relationships: 2 species living in close association ○ Mutualism: 2 interactive species benefit from each other (pollinators and producers) ○ Parasitism/Parasitoids: animals that lay eggs inside other organisms (their host) and allow their parasitoid larvae (offspring) to slowly consumer host to death (wasps and flies) ○ Commensalism: 1 species benefits, other is neither harmed or helped (fish hiding in coral) Competition: struggle of individuals to obtain a shared limiting resource ○ Competition Exclusion Principle: when 2 species (have the same fundamental niche) compete for the same limited resource, they cannot coexist One will outcompete the other, leading to extinction or evolution Species with identical ecological needs cannot coexist ○ Resource Partitioning: 2 species divide a resource based on differences in their behaviour Temporal Resource Partitioning: separates resource at different times to use (owls and hawks hunt for prey at different times - AM/PM) Physical Resource Partitioning:physically separating a habitat into sections for each species Morphological Resource Partitioning: physical adaptation that allow each to want different resources Predation: one species (prey) serves a resource for another (predator) ○ Play a critical role of regulating prey population Prey develop defense mechanisms: chemical defense (evolution) or hiding/little movement (behavioral) Ecological Succession: predictable replacement of one species by another ○ Primary Succession: succession with base rock and no soil ○ Secondary Succession: occurs in areas that have been disturbed but have not lost soil (follows after natural disasters like hurricanes) Pioneer Species: like trees, ability to colonize new areas rapidly and grow well in full sunshine ○ Climax Community: successions final stage, stable stage of a plant and animal community that develops Species are organized into biomes by global climate patterns and into communities whose composition changes regulation ○ Regions differentiated by latitude, time, habitat, size, & distance from other communities  All species have a range of tolerance: limits to the abiotic conditions they can tolerate ○ Temperature, salinity, humidity, pH ○ Fundamental Niche:the suite of abiotic conditions under which a species can survive, grow, and reproduce, limited by the species range of tolerance ○ Realized Niche: the range of abiotic and biotic conditions of which a species actually lives Species Richness: number of different kinds of species in the area (important but not a good indicator of diversity) Species Evenness: relative abundance of species Shannon Index of Diversity: tells the species evenness ( formula ) Pi = species #/total population # Theory of Island Biodiversity ○ Size:larger area easier colonized and more resources ○ Proximity:more colonization if closer to sources of biodiversity Order of 5 mass extinction: Ordovian, Devonian, Permian (largest mass extinction), Triassic, Cretaecous, Anthropocene Extinction (current) “Oh Don’t Pretend To Care.” Extinction has 3 levels ○ Local Extinction: ie. Grizzly Bear in California ○ Ecological Extinction species population drops so low it cannot fulfil their ecological role (ex. Honey Bees) ○ Biological Extinction Either completely gone, expired OR one left/unable to mate ie. White Rhino – only one male rhino Anthropocene Extinction - (1/20 min → 3/hr → 72/day) ○ the cause of the extinction is aware of causing the extinction and can prevent it, if it chooses to 1. Habitat Loss - ie. Deforestation (trees = homes) 2. Invasive Species - can outcompete native species causing significant ecological damage and biodiversity loss a. Caused by human activities like global trade, transportation and land use changes b. Population size cannot be regulated by native predators c. Ex. Rats in Hawaii - outcompete native species for resources and prey on the eggs of ground-nesting birds, reducing reproductive success. 3. Pollution a. Bioaccumulation: When an organism is taking in more and more toxins over time, such as a whale that is eating more and more plastics  b. Biomagnification: An organism high up in the food chain is exposed to higher concentrations of a toxin because the toxins accumulate in the organisms below it it the food chain 4. Climate Change - carbon cycle, causes change in climates for certain species range of tolerance/fundamental niche and loss of habitats in colder areas (polar bear) 5. Overharvesting= taking species (plants) faster than the rate when they can reproduce/replenish ○ Common Characteristics of Extinction - Prone Species Specialist: specific diets and nesting sites a species might depend on could disappear Large Size: these species will require a large habitat to find enough food and support themselves Slow Reproductive Rate: populations do not easily recover from overharvesting Migratory Lifestyle: species depend on healthy ecosystem at both ends of their migration and a safe migration route Perceived as valuable to humans: humans will overharvest these species for esthetic or medicinal use or as pets Perceived as a threat: large predators are seen as threat to self or livestock and ○ Single Species Approach: setting habitat aside, captive breeding programs, endangered species list India commiting to saving the Tigers ○ Ecosystem Approach: creating more wildlife refuges, national parks (Yellowstone National Park was the first national park), and marine sanctuaries ○ Ecological Restoration: restoration of local habitats, re-naturalization of ecosystems, reintroduce Keystone species Keystone: play a more significant role in their ecosystems than their relative abundance would suggest – can create or maintain habitat for other species Plastic are made from fossil fuels and used many ways globally ○ Never decompose, get smaller and smaller, gets eaten and enters the food chain/entangling wildlife (in the ocean and on land) ○ Made from raw materials with different densities –sinks or floats ○ Most plastic is not recyclable and get around by wind or water ○ Laced with Persistent Organic Pollutants (POPs) Persistent Organic Pollutants do not decay and can accumulate in organisms (bioaccumulation) and enter the food chain (biomagnification) ○ Plastics are treated with toxic chemicals BPAs (durable) or PBDA (fire)  ○ In water often stick to plastic surface Ways to Avoid Plastics ○ Bring reusable items when you shop and at ○ Say no to plastic items ○ Buy things with less plastic packaging ○ Support bans and taxes on plastics ○ Never litter