Unit 2 - The Living World: Biodiversity PDF

Unit 2 - The Living World: Biodiversity Objective/EKs/Skill 2.1 Biodiversity & Ecosystems  Biodiversity Basics Diversity of life forms in an ecosystem; measured on 3 different levels: Ecosystem diversity: the number of different habitats available in a given area Species d...

Unit 2 - The Living World: Biodiversity Objective/EKs/Skill 2.1 Biodiversity & Ecosystems  Biodiversity Basics Diversity of life forms in an ecosystem; measured on 3 different levels: Ecosystem diversity: the number of different habitats available in a given area Species diversity: the number of different species in an ecosystem and the balance or evenness of the population sizes of all species in the ecosystem Genetic diversity: how different the genes are of individuals within a population (group of the same species) ⛰ Higher biodiversity = higher ecosystem/ population resilience to disturbance Species Richness & Evenness Richness (S) is just the total number of different High richness is generally species found in an ecosystem a good sign of ecosystem health (more species Evenness is a measure of how all of the individual means more quality organisms in an ecosystem are balanced between resources like H2O & soil) the different species Evenness indicates if there are one or two dominant species, or if pop. sizes are well balanced  Genetic Diversity is Beneficial Genetic diversity = measure of how different the genomes (set of genes) are of the individuals within a population of a given species There is genetic diversity in all pops. because random mutations in copying of DNA & recombination of chromosomes in sex cells of parents leads to new gene combinations & new traits in offspring ⛰The more genetic diversity in a pop. the better the population can respond to environmental stressors like drought, disease, or famine More genetic diversity = higher chance that some of the individuals in a pop. have traits that allow them to survive the environmental stressor  Bottleneck Event An env. disturbance (natural disaster/human hab. destruction) that drastically reduces pop. size & kills organisms regardless of their genome Surviving pop. is smaller and because individuals died randomly, it doesn’t represent the genetic diversity of the original pop. ⛰Bottleneck events reduce genetic diversity Because the population is smaller & less genetically diverse, it’s even more vulnerable to future env. disturbances  Inbreeding Depression Inbreeding is when organisms mate with closely related “family” members Leads to higher chance of offspring having harmful genetic mutations because they’re getting similar genotypes from both parents Smaller populations are more likely to experience inbreeding (difficult to find non-related mate) Ex: Florida panther pop. decreased down to 30 in 1900s due to hunting & hab. loss. Inbreeding depression = kinked tails, heart defects, low sperm count, undescended testicles (saved in 95’ by pumas from Texas)  Ecosystem Resilience Resilience = the ability of an ecosystem to return to its original conditions after a major disturbance (wind storm, fire, flood, clear-cutting, etc.) ⛰Higher species diversity = higher ecosystem resilience High species diversity means greater likelihood that some plant species can survive the disturbance and stabilize the ecosystem (by providing food, habitat to animals, anchoring soil, cycling energy, etc.) Practice FRQ 2.1 Describe one of the three levels of biodiversity. Explain how high biodiversity at the level you described is beneficial to ecosystems. Eco$y$te m $ervices Objective/EKs/Skill Ecosystem Services = $$$ ⛰ Goods and services provided by natural ecosystems that are beneficial to humans (often monetarily or life-sustaining) Provisioning Regulating Supporting Cultural Goods taken directly Natural ecosystems Natural ecosystem Money generated by from ecosystems or regulate and processes that sustain recreation (parks, made from natural stabilize climate, air ecosystems & allow camping, tours) or resources (wood, quality, water quality, them to support life scientific knowledge paper, food) soil, biodiversity Humans Disrupt Ecosystem Services ⛰ Human activities disrupt the ability of ecosystems to function, which decreases the value of ecosystem services they provide This has ecological (natural) and economic (money-based) consequences Examples Clearing land for agriculture/cities removes trees that store CO2 (more CO2 in atm. = Increased atmospheric temp. = more storm damage & crop failure) Overfishing leads to fish population collapse (lost fishing jobs and lower fish sales in the future)  Provisioning Services Goods/products directly provided to humans for sale/use by ecosystems Ex: Fish, hunting animals, lumber (wood for furniture/buildings) naturally grown foods like berries, seeds, wild grains, honey Goods/products that are made from natural resources that ecosystems provide Ex: paper, medicine, rubber ⛰Disrupted by overharvesting, water pollution, clearing land for agriculture/urbanization  Regulating Services ⛰ Benefit provided by ecosystem processes that moderate natural conditions like climate, air quality, biodiversity, soil quality Examples Filtration & purification of water by wetlands Pollination (aids plant reproduction, food production, biodiversity) Trees sequester CO2 via photosynthesis, lessening atmospheric warming & costly impacts like storm damage/crop loss Trees filter air by absorbing air pollutants which reduces health care costs for treating diseases like asthma and bronchitis ⛰Disrupted by deforestation, pollinator hab. loss, filling in wetlands  Supporting Services ⛰ Natural processes that sustain ecosystems, allowing them to support life and all of the other ecosystem services Examples Photosynthesis, soil creation, nutrient cycling, habitat & food creation for plants and animals (all of these processes support ecosystem function, allowing them to support life) Essentially, everything needed to maintain functioning ecosystems, supporting all of the other ecosystem services ⛰Habitat loss due to deforestation, agriculture, urbanization  Cultural Services ⛰ Revenue from recreational activities (hunting/fishing licenses, park fees, tourism-related spending) & profits from scientific discoveries made in ecosystems (health/agriculture/educational knowledge) Examples Beautiful landscapes draw tourists who pay to enter parks, spend money at local stores/restaurants, or camping fees Fishermen pay for fishing licenses to catch fish in clean rivers Scientists learn about plant compounds that can lead to creation of new medicines which are sold for profit ⛰Disrupted by deforestation, pollution, urbanization  Practice FRQ 2.2 Describe an ecosystem service that intact forest ecosystems provide for humans. Identify one human activity that could degrade this ecosystem service and explain how the activity decreases the value of the ecosystem service. 2.3 Theory of Island Biogeography Objective/EKs/Ski ll  Island Biogeography Study of ecological relationships & community structure on islands - Islands can be actual islands in a body of water, or figurative habitat islands such as Central Park in New York City or National Parks (natural habitats surrounded by human-developed land) Two basic “rules” or observations of Island Biogeography: Larger Islands support more total species The larger the island, the greater the ecosystem diversity Greater ecosystem diversity = more food & habitat resources More niches, or “roles” organisms can play in the ecosystem Islands closer to the “mainland” support more species Easier for colonizing organisms to get to island from the mainland More colonizing organisms = more genetic diversity in new pop.  Larger Islands Support More Larger islands = Species ○ higher ecosystem diversity ○ More available “niches” or roles Ex: all the different food sources available to birds on Galapagos ○ Larger pop. sizes (more genetically diverse and more resistant to environmental disturbance) ○ Lower extinction rate (species less likely to die off) Positive correlation between island size & species richness  Distance to Mainland Closer to mainland = higher species richness Easier for more species to migrate to island from mainland (swim/fly) More continual migration of individuals to the island habitat ○ Frequent migration brings more genetic diversity & larger pop. size Inverse relationship between island distance from mainland & species richness The further away from mainland, the fewer species  Evolution on Islands Islands have limited space & resources, creating unique conditions for evolution ○ More pressure for species to adapt to narrower niches (more specific food/hab.) Adaptive radiation = single species rapidly evolving into several new species to use diff. resources & reduce competition ○ Ex: Galapagos Finches Different beaks quickly evolve to fit variety of different food sources on an Island One colonizing species from mainland quickly evolves to many slightly different species to adapt to new island conditions Practice FRQ 2.3 Describe the processes of colonizing an island habitat. Describe how the island’s distance from the mainland influences the number of species that will colonize the island habitat.  2.4 Ecological Tolerance 29 Objective/EKs/Skill  Ecological Range of Tolerance ⛰ Range of conditions such as temperature, salinity, pH, or sunlight that an organism can endure before injury or death results ⛰ Species and individual organisms both have a range of tolerance for all the different abiotic conditions of their habitat Ex: Salmon have a basic range of tolerance for temperature from 6o to 22o C. But some individual salmon have adaptations that give them a range of tolerance that is outside the basic range for the species, Due to genetic biodiversity Makes populations of salmon more resistant to disturbances, like global warming  Ecological Range of Tolerance - Zones ⛰ Optimal range: range where organisms survive, grow, and reproduce ⛰ Zone of physiological stress: range where organisms survive, but experience some stress such as infertility, lack of growth, decreased activity, etc. ⛰ Zone of intolerance: range where the organism will die Ex: thermal shock, suffocation, lack of food/water/oxygen  FRQ Writing Tips ⛰ On FRQs about human activities or natural events that cause environmental disturbance, connect answer to ecological range of tolerance If possible, connect human activity to climate change (electricity generation, transportation, agriculture) all release CO2 which causes climate change and global warming Global warming shifts temperature outside the range of tolerance for many tree species, causing their populations to decline OR Global warming warms the ocean, shifting temperature outside range of tolerance for many fish species, causing die-offs  FRQ Writing Tips ⛰ Try to connect a shift in range of tolerance to a specific kind of physiological stress Ex: suffocation, thermal shock, lack of water/food/nutrients/oxygen Global warming warms the ocean, shifting temperature outside range of tolerance for many fish species. Since global warming increases ocean temperature and warm water holds less oxygen, fish may suffocate due to lack of oxygen. Global warming warm can increase droughts. With increased droughts, rainfall patterns may shift outside the range of tolerance for many plant species. Without enough rainfall, these species may suffer population decline as their roots are unable to absorb enough water from the soil. Practice FRQ 2.4 Identify the author’s claim 2.5 Natural Disruptions to Ecosystems  Natural Disturbances ⛰A natural event that disrupts the structure and or function of an ecosystem Ex: Tornadoes, hurricanes, asteroids, forest fires, drought ⛰Natural disturbances can be even greater than human disruptions Can occur on periodic, episodic, or random time frames Periodic : occurs with regular frequency (ex: dry-wet seasons) Episodic : occasional events with irregular frequency (ex: hurricanes, droughts, fires) Random : no regular frequency (volcanoes, earthquakes, and asteroids)  Natural Climate Change ⛰ Earth’s climate has varied over geologic time for numerous reasons Ex: Slight changes in earth’s orbit & tilt cause mini ice ages & warmer periods as earth shifts slightly closer to & further from sun  Natural Climate Change ⛰ Sea level has varied over geological time as glacial ice on earth melts & forms  Env. Change = Hab. Disruption ⛰ Major environmental disturbances result in widespread habitat changes and or loss Ex: Rising sea level floods coastal & estuary habitats  Migration ⛰ Wildlife may migrate to a new habitat as the result of natural disruptions Ex: wildebeests migrating to follow rain patterns of African savanna - Ocean species moving further north as water temperature warms - Bird migration & breeding shifting earlier as insect hatching shifts earlier with warming climate  Describe the relationship between latitude and change in first leaf date Practice depicted in the graph. Explain why FRQ you think this relationship exists. 2.5 2.6 Adaptation s Objective/EKs/Skill  Fitness & Adaptation ⛰ All populations have some genetic diversity, or variability in genomes of individuals; Genetic diversity exists because: ❖ Random mutations while DNA is being copied create new traits ❖ Crossing over in parent chromosomes creates new combinations of genes (and therefore traits) ⛰ Adaptation: a new trait that increases an organism’s fitness (ability to survive and reproduce)  Adaptation & Natural Selection ⛰ Natural selection : organisms that are better adapted to their environment survive and reproduce more offspring ❖ Individuals with adaptations pass them on to offspring & individuals without adaptations die off, which leads to the entire population having the adaptation over time (evolution) ❖ Selective pressure/force: the environmental condition that kills individuals without the adaptation Predation (hawk) = selective pressure  Environmental Change & Evolution ⛰ The environment an organism lives in determines which traits are adaptations ❖ As environments change, different traits may become adaptations & old traits may become disadvantages ❖ Ex: a drought can kill off finches with smaller beaks, making larger beaks for cracking harder seeds an adaptation  Pace of Evolution ⛰ The more rapidly an environment changes, the less likely a species in the environment will be to adapt to those changes ❖ If the pace of environment change is too rapid, many species may migrate out of the environment or die-off completely ❖ Ex: if the ocean warms too quickly (⬇ dissolved O2), many species of fish may not be able to migrate quickly enough to colder waters ⛰ The more genetic diversity in a population, the better they’re able to adapt to environmental change (higher chance that some individuals have good mutations) The longer the lifespan of the organism, the slower the rate of evolution ❖ Ex: bacteria & viruses can adapt and evolve in days Humans evolution = thousands-mil. years Practice FRQ 2.6 This data table shows the beak size of 20 finches from two different islands in the Galapagos. Describe the difference in beak size between the two islands. Make a claim about the reason for this difference in beak size.  2.7 Ecological Succession Objectives/EKs/Skill Ecological Succession A series of predictable stages of growth that a forest goes through Two types of succession: ⛰ Primary Succession: starts from bare rock in an area with no previous soil formation Moss & lichen spores carried by the wind grow directly on rocks, breaking them down to form soil ⛰ Secondary Succession: starts from already established soil, in an area where a disturbance (fire/tornado/human land clearing) cleared out the majority of plant life Grasses, sedges, wildflowers, and berry bushes have seeds dispersed by wind or animal droppings Stages of Succession Stages are characterized by which types of plant species dominate the ecosystem; different species are adapted to the conditions of the different stages ⛰ Pioneer or early succession species appear first, when the ground is simply bare rock, or bare soil after a disturbance Characteristics: seeds spread by wind or animals, fast growing, tolerant of shallow soil and full sunlight Ex: moss, lichen (bare rock) | wildflowers, raspberries, grasses/sedges ⛰ Mid-successional species appear after pioneer species have helped develop deeper soil with more nutrients by their cycles of growth/death Characteristics: relatively fast growing, larger plants that need deeper soils with more nutrients than pioneers, sun tolerant Ex: shrubs, bushes, fast-growing trees like aspen, cherry, and pine Stages of Succession ⛰ Late successional or climax community species appear last, after soil is deepened and enriched with nutrients by cycles of growth and death by early & mid successional species Characteristics: large, slow-growing trees that are tolerant of shade and require deep soils for large root networks Ex: maples, oaks, other large trees Primary Succession Occurs in an area that hasn’t previously been colonized by plants (bare rock) Ex: volcanic rock, rock exposed after glacial retreat ⛰ Moss and lichen (spores dispersed by wind) are able to grow directly on rock by secreting acids that break down rock & release minerals containing nutrients they need (N/P/K) Chemical weathering of rocks by moss & lichen combined with organic matter from moss & lichen dying form initial shallow soil Secondary Succession Occurs in an area that already has established soil, but has had most plant life removed by a disturbance ⛰ Pioneer species are still wind-dispersed seeds of plants that are fast-growing and sun tolerant, but grasses/wildflowers/weeds instead of moss/lichen Soil is already established & sometimes even enriched by nutrient-rich ash from fire; overall more rapid process than primary succession Practice FRQ 2.7 Based on the graph below, explain whether spruce trees are an early, middle, or late successional species.