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Assemblage of many populations that live in the same place at the same time.
Communities at the largest scales. Examples: terrestrial, coastal, and aquatic
Focuses on why certain areas have high numbers of species and called species rich, while other areas have low numbers of species and are called species poor.
A process in which species composition changes over time and in particular after a disturbance, such as a fire or a flood.
Describes the passage of energy and nutrients through communities. Deals with the flow of energy and cycling of nutrients among organisms within a community and between organisms and their environment.
A living, biotic community and its nonliving abiotic environment.
-ology= study of
Natural process by which species die out.
Describes the recent elevated loss of species. Growth of human population is thought to have led to this increase in extinction.
Studies how to protect the biological diversity of life at all levels.
deforestation (prime cause of extinction), the conversion of habitat to agricultural land (can create soil erosion, increased flooding, declining soil fertility, silting of rivers, and desertification), urbanization, draining of swamps, strip mining, quarrying, dam construction, river channelization, and other forms of land modification.
Species moved by humans from a native location to another location.
-Usually introduced for agricultural or landscaping purposes or as sources of timber, meat, or wool.
-Others, like plants, insects, or marine organisms, are unintentionally transported via the movement of cargo by ships or planes.
-Causes extinction of other species between introduced and native species.
-Profit from selling rare organisms
May cause global change via climate alterations.
-carbon dioxide (most important pollutant, effects global warming)
-fossil fuels (if isn’t cut drastically, will cause 15-37% of species to become extinct in that area by 2050)
-Amphibians: ability to fight infection depends strongly on environmental temperature, which is gradually changing
-Mammals: Require large habitat. Larger mammals prone to extinction from habitat destructions, or overexploitation (big cats, fur and pelts)
The study of interactions among organisms and between organisms and their environment. Two types.
1) Biotic- Interactions among living organisms.
2) Abiotic- Interactions among organisms and their physical environment.
Interactions between living organisms and their physical environment.
Interactions between living organisms.
-genes, cells, organs, organisms, population, communities
genetic systems, cell system, organ system, organismatic system, population system, ecosystems)
The idea that all properties of a system cannot be determined or explained by it’s components alone.
Ex: Forest community is not just a bunch of trees. Must understand how leaves produce sugar from sun, understand understory trees, etc.
Ecology is to environmental science as physics is to engineering ecology: Provides framework.
Can describe ecological phenomena and predict patterns.
-Visualization of complex system
-Ex: Population growth
1) Over many generations the physical environment is a guiding force of natural selection
2) Over shorter period, the physical environment influences behavior and physiology.
In higher latitudes (Russia/Canada) the sun’s rays hit Earth obliquely and are spread out over more of the planet’s surface than in equatorial areas. More heat is also lost in atmosphere of higher latitudes because Sun’s rays travel greater distance through atmosphere, which allows more heat to be dissipated by cloud cover.
Ex: At the Tropics, both cloudiness and rain reduce average temperature so that temp. does not continue to increase toward equator.
One cell circulation. Solar energy drives winds, influencing global circulation of atmosphere. Warm air at equator rises and cools. As it cools, it becomes less buoyant but it cannot sink back down because of warm air that's already moved in to replace it. Instead, it goes north and south. It starts to fall back to earth at 30 degrees.
Where the Hadley cell sank (30)
They are areas of high pressure and site of world’s hot deserts because subsiding air is dry since it already released all of it’s moisture.
-Winds usually weak near this zone of descending air: horse latitudes.
Equatorial flow is deflected by the Coriolis force and forms the reliable trade winds. In Northern Hemisphere, trades are from NE, and vice versa. (SE in South)
Trade winds from both hemisphere meet near equator at Intertropical Convergence Zone (ITCZ), aka the doldrums (because light winds and humid).
Elevation and proximity of landmass to water affects temperature and precipitation. Global temperatures and wind patterns affect climate.
-Increased relative humidity
-Molecules spread apart, less pressure on them
-Air gets cooler, humidity goes up
-Where the air is rising= rain
Where the air is coming down= Humidity increases and dry (susistence zone)
Humans undergo acclimation to different climates. Going to Colorado. Less oxygen so harder to breathe. Takes 3 weeks to make more blood cells so we’ll be able to acclimate overtime. Eastern phoebe birds grows downfeathers during winter, but molts during summer. It is acclimating, it's phenotype changed.
water absorbs light, preventing photosynthesis at depths greater than 100 m.
-Sufficient light penetrates to allow photosynthesis to exceed respiration at this zone.
-Algae grow at different ocean depths according to light. Deeper=less types of light
The level at which photosynthate production equals the energy used by respiration is the lower limit of the photic zone
Important property of freshwater biomes. This is the amount of oxygen that occurs in microscopic bubbles of gas mixed with water. Supports aquatic life.
-Directly via diffusion from atmosphere
-From aquatic plants or algae that release oxygen via photosynthesis
-Waterfalls and water traveling over rocks, which trap air.
-In estuaries, fresh water stays above salt water
-Dense water causes turnover
Molecules don’t pull apart because hydrogen bonds between molecules of water. Bugs can walk on water. Soap breaks the surface tension.
1 (energy required to raise 1 g of water to 1 degree celsius)
-Water needs lots of energy to absorb/lose heat
-Helps buffer aquatic habitats and thermal regulation of organisms
Relationship between density and temperature explains it. Advantageous to fish because the frozen surface insulates the rest of lake from freezing. In entire lake froze, all fish would die.
-Usually semi-enclosed bodies of water that have at least one source of freshwater feeding into them but also a connection to open sea.
-Rich environment because of marine and freshwater species
The process of aging and degradation of lakes.
-Organic layer, partially decomposed. Subdivided into two more layers:
1. Oi layer: Litter layer. Leaf litter layer fluctuates seasonally.
2. Oa layer: Humus layer (zone of decomposition). Does not fluctuate.
-Small amounts of weather mineral parent material
-Weathered parent material like bedrock.
Movement of solutes through soil
-During El Nino, a much greater depth of surface water is warmed in the tropical eastern Pacific Ocean.
-Upwelled water from warmer layer contains fewer nutrients, leading to a broader, relatively nutrient-depleted surface layer.
-Reduces amount of phytoplankton and density of fish dependent on them.
-As wind blows, friction between the air and water surface creates small ripples.
-Once ripples have formed, the wind has something to push against and the waves can increase in size.
-salinity (haline) gradients
Gravitational Pull of the Moon and Sun.
-More buildings and sidewalks give up heat faster and absorb solar radiation and reradiate energy
-Urban landscape is nonporous and most rainfall is lost as runoff before evaporation can cool area
-Construction materials are conductors of heat
-Favors individual’s at one extreme of a phenotypic distribution that have greater reproductive success in a particular environment.
-A new allele may be introduced into a population by mutation, and the new allele may confer a higher fitness in individuals that carry it.
-If the homozygote carrying the favored allele has the highest fitness value, directional selection may cause this favored allele to eventually become predominant in the population.
-Moths. Starting population, light color was the highest (left curve). Population after directional selection, dark color is favored (right curve).
-Favors the survival of individuals with intermediate phenotypes.
-Extreme values of a trait are selected against.
Examples: Clutch size. Too many eggs= not enough food. Too few eggs= contributes few individuals to next generation. Starting population: broad curve. Population after stabilizing selection, steep middle curve.
-Type of natural selection that maintains genetic diversity in a population.
-Two or more alleles are kept in balance and therefore are maintained in a population over the course of many generations.
-Does not favor one particular allele in a population.
Heterozygote advantage (sickle cell anemia). Frequency-dependent selection (fitness of one phenotype is dependent on its frequency relative to other phenotypes in a population) [negative frequency: rare phenotype favored, positive frequency: common phenotypes have an advantage]
-Favors survival of individuals at both extremes, rather than the intermediate.
-Fitness value of one genotype are higher in one environment, while fitness values of the other genotype are higher in another environment.
Example: Starting population of bentgrass is metal sensitive (left curve). Population after disruptive selection has two humps on right & left (metal sensitive and metal resistant)
Ex: Finches had origins in mainland South America. Somehow got blown over to islands. Finches adapted (natural selection) and on different islands adapted differently.
-Environmental conditions very
-Disruptive selection- Push in middle for or against something
-Individual Female (bet hedging)?
Ex: Arctic fox & gray fox. Population is isolated in terms of types of genes.
Arctic: Only goes down (distance) so far. Heavy fur, light color, short tail, ears, legs, & nose.
-Small endotherms like: easter phoebe, can’t feed below 4, shrews die after 1 day of not eating, vampire bat can’t survive below 10 b/c of poor capacity for thermal regulation.
-Freezing temperature is the single most important factor limiting the geographic distribution of tropical and subtropical plants.
-Low-elevation tropical areas are the only frost-free
-Many plants in cold climates exist only below ground, as roots, or close to ground, insulated by snow.
-Begin growth when spring warms temperature, new buds form at end of summer, dormant over winter, ready by spring.
Ex: Vampire bats. Our bats hibernate or migrate.
Ex: Osmolarity- Since cells are hypotonic to freshwater, they pull water in and have kidneys and gills that store salt. Have active transport mechanisms to get rid of salt to life in ocean.
-Rainfall, and temperature to a lesser degree, were the overriding influences on density of thrips.
-Temperature affected reproductive rates
-Rain dislodged them and killed them
Ex: Rams fighting. Competition among males.
Ex: Predator-prey. Fox eats hare.
Ex: Bluebirds are born naked with no feathers. Most mammals produce milk, males not as necessary like in birds.
Ex: Ducks hatch, dry, eat on their own, walk and follow mom around. Deer.
Ex: cockroach, dandelion,
Ex: elephant, saguaro
Ex: Color of plumage, courtship song
-Some male birds & mammals congregate in communal courting grounds called leks: males all displaying. Females come through and mate. Male gets to mate with multiple females.
-Female competition for social rank.
-Less ranked female mates with less ranked male.
Fitness not only related to your own children, but others related to you: Kin
-You save the equivalent of yourself
-2 kids: 50% each= 1 of you
-8 cousins: 1 of you
-Kin selection helps explain the altruistic act of alarm calling
Kin selection and natural selection pushes organisms to produce more offspring of highest fitness.
Ex: food gathering or foraging often involves decisions about whether to remain at a resource patch and look for more food or to look for new patch
Ex: Northwest crows built platforms above rocks with welps. Bigger ones need to be dropped from higher heights. Optimal value for medium whelks. Gave more food than small ones but not as high energy cost.
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