Unit B

• Ecotones

  Border areas between ecosystems

  Has more biodiversity than both ecosystems
• Benefits of biodiversity

  More biodiversity means less fragile ecosystem

  More species as food source, alternative prey to maintain food web
• Artificial vs. Natural ecosystems

  Artificial - planned/maintained by humans

  Natural - organisms are free to do whatever they want

  Humans can still interact with natural ecosystems
• Niches

  A role an organism plays in an ecosystem

  Includes everything it does, such as surviving and reproducing

  Each species has a different niche, reducing competition for resources
• Biome

  Region with a specific climate

  Usually has a dominant species

  Ecosystems in biomes support organisms that may not survive elsewhere
• Taiga biome

  Also called the boreal forest

  Northern Alberta + Rocky Mountains

  Dominated by conifers (pine trees)

  Ecosystems in different parts of taigas vary differently
• Muskeg in Taigas

  Swampy ground in the summer

  Has permafrost (permanently frozen soil)

  Slow decomposition

  Plants have fibrous root systems
• Grassland biome

  Most fertile soil in the world

  Grass with deep roots create biomass to decompose

  Lower biodiversity than forests
• Deciduous forests in grasslands

  Found in areas with rainfall in between taiga and true grasslands

  Can be found near bodies of water

  Trees need less water than conifers
• Lake ecosystems

  Littoral zone - Plants grow near the shore

  Limnetic zone - Past littoral, enough light for plankton to photosynthesize

  Profundal zone (optional for lakes) - Detritus feeders eat dead animals and plants from above
• Layers of Soil

  Litter - Upper layer of soil, made of decomposed leaves/grasses

  Topsoil - Rock mixed with black decaying matter (humus), usually dark

  Rich with nutrients and minerals for plants

  Subsoil - More rock, less organic matter, lighter in color

  Bedrock - The end of soil
• Soil acidity

  Alkaline soils - Basic

  Water cycle affects acidity

  Conifers and mosses like acidic soils but not other plants
• Water in ecosystems

  Groundwater - water in the ground 🙄

  Soil above water table is saturated

  Marshes/swamps have a shallow water table

  Roots don't need to reach as deep
• Factors affecting terrestrial ecosystems

  Soil

  Water availability

  Temperature

  Sunlight
• Factors affecting aquatic ecosystems

  Chemicals

  Temperature & Sunlight

  Water Pressure

  Seasonal Variations
• Chemicals in aquatic ecosystems

  Freshwater vs. saltwater

  Oxygen PPM

  Other dissolved materials
• Temp and sunlight in aquatic ecosystems

  Shallower ecosystems - More light, warmer temperatures

  Deeper ecosystems - Less light, colder temperatures
• Water pressure in aquatic ecosystems

  800 times denser than air

  Pressure increases one hundred kPa for every ten meters of depth
• Seasonal variations in Canadian Lakes

  Winter - lakes covered by ice, blocks oxygen from entering, acts as insulator

  Layers: Epilimnion (zero degrees), Thermocline, Hypolimnion (four degrees)

  Spring - Ice melts, oxygen unblocked

  Wind makes waves, increasing surface area and oxygen dissolving rate

  Spring turnover: Surface water sinks, holding lots of oxygen

  Summer - Upper layers warm, lower layers cold

  Little oxygen transfer, hypolimnion still has most oxygen

  Warm epilimnion means less dissolved oxygen

  Fall - Surface water cools

  Fall turnover: Renews oxygen in lower levels
• Biotic Potential

  Maximum number of offspring if unlimited resources

  Many factors limits populations

  Carrying capacity - Maximum population that can be supported at once

  Population can go over, but will go back down eventually
• Limits of tolerance

  Law of the minimum - The nutrient with the lowest amount in the ecosystem is the limiter for growth

  Law of tolerance - Organisms can tolerate certain ranges of abiotic factors

  Greater the range, greater the survivability
• Density independent vs. dependent factors

  Density-independent factors - Affects populations regardless of population density

  Density-dependent factors - Affects members based off of density
• Forestry Practices

  Slash and burn - Clearcut, then burn debris for nutrients

  Used in tropical areas for agriculture

  Selective Cutting - Only cut a few trees
• Prescribed Burns

  Intentional, controlled fires to to clear land and burn stubble
• Types of lakes

  Oligotrophic - Low nutrient levels

  Eutrophic - High nutrient levels
• Water Pollution

  Organic solid waste - Sewage and waste from food processing

  Disease-causing organisms - From sewage and animal wastes, can cause waterborne outbreak

  Inorganic solids and dissolved minerals - Mining, fertilizers, salt from runoff

  Thermal energy - Decreases dissolved oxygen

  Organic compounds - Oil, pesticides, phosphates
• Water quality indicators

  Coliform Bacteria - Naturally in intestines

  More coliform bacteria means more harmful wastes and diseases

  Dissolved Oxygen: Color change, trout population

  Biological Oxygen Demand (BOD) - Amount of oxygen to decompose matter in twenty degrees over five days
• Six Kingdoms

  Eubacteria - Prokaryotic (No nucleus), can live anywhere

  Archaebacteria - Prokaryotic, salt lakes, hot springs, animal guts

  Protista - Eukaryotic (Has nucleus), aquatic and moist habitats

  Fungi - Most are multicellular, terrestrial

  Plantae - Multicellular, terrestrial

  Animalia - Multicellular, terrestrial and aquatic
• Kingdoms and cell walls

  Eubacteria - Yes, has peptidoglycan

  Archaebacteria - Yes, doesn't have peptidoglycan

  Protista - No

  Fungi - Yes

  Plantae - Yes

  Animalia - No
• Evolution

  Phylogeny - History of organism evolution

  All organisms evolve from protista
• Evolution from Paleontology

  Study of fossils

  Different species, different times in the past

  Organisms become more complex over time

  Similar species and fossils are located in similar areas
• Evolution from Biogeography

  Distribution of life across Earth

  Endemic - Species found nowhere else

  Remote islands have endemic species
• Evolution from anatomy

  Homologous features - Similar structure, different function

  Analogous features - Similar structure and function but different origin

  Vestigial features - Structures with no function (present in many organisms)
• Evolution from Biochemistry

  Homologous and vestigial genes present in all species

  Artificial selection - Choosing and breeding better traits
• Theory of Evolution

  Organisms want to live

  Natural Selection - Better traits survive and reproduce

  Evolution - Better traits become more common
• Mutations

  Random changes in DNA

  Caused by environmental factors or errors

  Fitness - Reproductive success

  Neutral mutation - Doesn't change fitness

  Harmful mutation - Reduces fitness

  Beneficial mutation - Increases fitness

  Most mutations are neutral or harmful
• Reproduction and Variability

  Asexual reproduction: Children identical to parent and siblings

  Sexual reproduction: Lots of variability in children

  Remember the dominant/recessive chart
• Speciation

  Forming a new species

  Allopatric speciation - Splitting a population so natural selection works differently on the groups over time

  Populations are split with physical barriers such as mountains and rivers
• Macroevolution

  Divergent evolution - Evolution splitting into different species

  Mass extinction reduces biodiversity