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Sep 16, 2024

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6 Scientific Principles of Sustainability

  1. Solar energy- The sun provides warmth and provides energy that plants use to produce nutrients
  2. Biodiversity- Astounding variety and adaptability of natural systems and species
  3. Chemical (nutrient) cycling- Circulation from the environment to organisms and then back to the environment
  4. Full-cost pricing- Include harmful environmental and health costs in market prices of goods and services
  5. Win-win solutions- Look for solutions that will benefit people and the environment
  6. A responsibility to future generations- Leave planet’s life-support system in same or better condition than it is now Key Components of Sustainability • Natural capital (Natural resources + Ecosystem services): • is the world's stock of natural resources, which includes geology, soils, air, water and all living organisms. • Natural resources: useful materials and energy in nature • May be inexhaustible (Solar), renewable (forest), or nonrenewable (exhaustible) (oil, coal, etc.) • Ecosystem services: • Processes provided by healthy ecosystems at no monetary cost to us- include providing resources such as food and water, maintaining habitats that support biodiversity, offering opportunities for recreation Key truth- We Are Living Unsustainably • Environmental degradation • Wasting, depleting, and degrading the earth’s natural capital • Human activities directly affect 83% of earth’s land surface • Urban development, crop and energy production, mining, timber cutting, and more • Species are becoming extinct at least 100 times faster than in prehuman times • Three major cultural events have impacted environmental sustainability
  7. Agricultural revolution
  8. Industrial–medical revolution
  9. Information–globalization revolution Earth’s Life • Classification based on cell structure • Prokaryotic (bacterial cells) • No distinct nucleus or internal parts enclosed by membranes • Eukaryotic • All nonbacterial organisms • Taxonomic classification • Kingdom, phylum, class, order, family, genus, species Importance of Biodiversity • Biological diversity is the diversity of life on earth • Species diversity • Includes species richness (# of different species) and evenness (distribution of abundance in an area) • Genetic diversity • Variety of genes in a population or species • Ecosystem diversity • Biomes: regions with distinct climates and species • Functional diversity • Variety of processes within ecosystems. Examples: energy flow and matter cycling Roles of Species in Ecosystems • Each species plays a specific ecological role called its ecological niche • Includes everything that affects survival and reproduction • Water, space, sunlight, food, and temperatures • Habitat is the type of ecosystem that it needs to survive • Generalist species • Broad niche—wide range of tolerance • Specialist species • Narrow niche—narrow range of tolerance Species Play Four Major Ecosystem Roles (KNOW EXAMPLES!!!!) • Native species normally live and thrive in a particular ecosystem. • Nonnative species migrate or are accidentally introduced into an ecosystem. • Invasive species are harmful nonnative species. • Indicator species provide early warnings of environmental changes. • Keystone species have a large effect on the types and abundance of other species. Evolution • Biological evolution • Earth’s life forms change genetically over time • Widely accepted scientific theory • Natural selection • Process by which species have evolved from earlier speciesEvolution • Biological evolution • Earth’s life forms change genetically over time • Widely accepted scientific theory • Natural selection • Process by which species have evolved from earlier species Evolution Depends on Genetic Variability and Natural Selection • Natural selection • Environmental conditions favor increased survival and reproduction of certain individuals in a population • Adaptive trait • Improves the ability of an individual organism to survive and reproduce at a higher rate than other individuals in a population KNOW EXAMPLES!!! And be able to explain how these examples help the species be successful in their environment Myths about Evolution through Natural Selection • Five common myths:
  10. Survival of the fittest means survival of the strongest.
  11. Evolution explains the origin of life.
  12. Humans evolved from apes or monkeys.
  13. Evolution is part of nature’s grand plan to produce perfectly adapted species.
  14. Evolution by natural selection is not important because it is just a theory. Factors Affecting Biodiversity • Speciation = how new species form. It takes place in two phases • Geographic isolation • Occurs first • Populations migrate or are separated by some other cause • Reproductive isolation • Mutation and change by natural selection occurs in the geographically isolated groups • Eventually prevents breeding between the groups Extinction Eliminates Species (1 of 3) • Extinction • Process in which an entire species ceases to exist • Endemic species • Found only in one area • Particularly vulnerable to extinction KNOW EXAMPLES!!! Earth’s Life-Support System Has Four Major Components • Atmosphere • Innermost layer is the troposphere • Contains the air we breathe • Stratosphere: contains ozone layer • Filters sun’s harmful UV radiation • Hydrosphere • All water vapor, liquid water, and ice • Oceans contain 97% of the planet’s water • Geosphere • Upper portion of crust contains nutrients organisms need to live, grow, and reproduce • Contains nonrenewable fossil fuels • Biosphere • Parts of atmosphere, hydrosphere, and geosphere where life is foundEarth’s Life-Support System Has Four Major Components • Atmosphere • Innermost layer is the troposphere • Contains the air we breathe • Stratosphere: contains ozone layer • Filters sun’s harmful UV radiation • Hydrosphere • All water vapor, liquid water, and ice • Oceans contain 97% of the planet’s water • Geosphere • Upper portion of crust contains nutrients organisms need to live, grow, and reproduce • Contains nonrenewable fossil fuels • Biosphere • Parts of atmosphere, hydrosphere, and geosphere where life is found Ecosystem Components Ecosystems Have Several Important Components • During photosynthesis, plants (Producers/Autotrophs) generate energy and emit oxygen • CO2 + H2O + solar energy → glucose + oxygen • Consumers (heterotrophs) cannot produce the nutrients they need • Primary consumers (herbivores) eat plants • Carnivores feed on flesh of other animals • Secondary and tertiary (or higher) consumers • Omnivores eat both plants and animals Ecosystems Have Several Important Components (3 of 7) • Decomposers (Fungi/Bacteria) • Consumers that release nutrients from wastes or remains of plants or animals • Nutrients return to soil, water, and air for reuse • Detritivores are different from other decomposers in that they consume material to break it down. Decomposers like bacteria and fungi don’t eat their food, they decompose it externally. Energy in an Ecosystem • Energy flows through ecosystems in food chains and webs • Food chain • Movement of energy and nutrients from one trophic level to the next • Food web • Network of interconnected food chains The Water Cycle • The hydrologic cycle collects, purifies, and distributes earth’s fixed supply of water • Incoming solar energy causes evaporation • Gravity draws water back as precipitation • Surface runoff evaporates to complete the cycle • Some precipitation stored as groundwater The Carbon Cycle • Carbon is the basic building block of carbohydrates, fats, proteins, DNA, and other organic compounds • Photosynthesis from producers removes CO2 from the atmosphere • Aerobic respiration by producers, consumers, and decomposers adds CO2 • Over millions of years, carbon in dead plant matter and algae may be converted to fossil fuels • Some CO2 dissolves in the ocean • Stored in marine sediments The greenhouse effect occurs when greenhouse gases in a planet's atmosphere insulate the planet from losing heat to space, raising its surface temperature. Four Laws of Ecology • Four principles or laws of ecology were proposed by Commoner in 1971.
  15. Everything is connected to everything else. (Interdependence)
  16. Everything must go somewhere.
  17. There is no free lunch.
  18. Nature knows best. • Observing these laws helps avoid going beyond ecological tipping points. • Examples of such tipping points include; disruption of cycles, reduction of biodiversity, climate change, ocean acidification, ozone depletion, overconsumption of water, and pollution. Species Interaction s (KNOW EXAMPLES) • Five types of species interactions affect resource use and species population sizes in an ecosystem
  19. Interspecific competition
  20. Predation
  21. Parasitism (+/- relationship)
  22. Mutualism (+/+ relationship)
  23. Commensalism (+/0 relationship) Oxpeckers and large mammals Gopher Tortoise burrows Worms and snails Competition for Resources • Most common interaction is competition • Interspecific competition • Competition between different species to use the same limited resources • Competitive exclusion principle states that two species cannot fully occupy the same niche although there might be some overlap Resource partitioning • Occurs when different species evolve specialized traits that allow them to share the same resources • Species may use only parts of resource • At different times • In different ways Predation & Prey • Predator feeds directly on all or part of a member of another species (prey) • Strong effect on population sizes and other factors in ecosystems • Methods of predation • Herbivores walk, swim, or fly to plants • Carnivores use speed, flight, and senses to locate prey • Predators adapt camouflage and chemical warfare • Coevolution • Changes in the gene pool of one species can cause changes in the gene pool of the other • Prey species have evolved ways to avoid predators • Camouflage • Chemical warfare • Warning coloration • Mimicry • Behavioral strategies Ecological Succession • Ecological succession • Normally gradual change in structure and species composition in a given system • Primary ecological succession • Involves gradual establishment of communities in lifeless area • Need to build up fertile soil or aquatic sediments to support plant community • Pioneer species such as lichens or mosses (grow on rocks and lead to soil nutrients) • Secondary ecological succession • Series of terrestrial communities or ecosystems develop in places with soil or sediment • Examples: abandoned farmland, burned or cut forests, and flooded land Limits to Population Growth • Population • Group of interbreeding individuals of the same species • Variables that govern changes in population size • Births, deaths, immigration, and emigration • Age structure • Pre-reproductive stage • Reproductive stage • Post-reproductive stage No Population Can Grow Indefinitely: J-Curves and S-Curves Populations of species can undergo exponential growth represented by a J-shaped curve (left) when resource supplies are plentiful. As resource supplies become limited, a population undergoes logistic growth, represented by an S-shaped curve (right), when the size of the population approaches the carrying capacity of its habitat. No Population Can Grow Indefinitely: J-Curves and S-Curves • Population growth in nature always limited (limiting factors: water, temperature, space, resources, predator exposure, disease) • Environmental resistance • Sum of all factors that limit population growth • Carrying capacity • Maximum population of a given species that a particular habitat can sustain indefinitely • Overshoot results in population crash No Population Can Grow Indefinitely: J-Curves and S-Curves Reproductive Patterns TABLE 5.1 Typical traits of r-selected and K-selected species Trait r-Selected Species K-Selected Species Reproductive potential High Low Population growth rate Fast Slow Time to reproductive maturity Short Long Number of reproductive cycles Many Few Number of offspring Many Few Size of offspring Small Larger Degree of parental care Low High Life span Short Long Population size Variable with crashes Stable, near carrying capacity Role in environment Usually prey Usually predators Survivorship Curves • Survivorship curve • Shows the percentages of members of population surviving at different ages • Late loss (K-selected species) • Early loss (r-selected species) • Constant loss (many songbirds)