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Factors of Community:
1. Interactions between the climate and topography
a. “Rainfall, soil, temperature”
2. The food and resources that grow
3. Other specific resources necessary for a species to survive and adapt to. (Ecological niche)
4. Species interaction
5. Physical disturbances, addition/removal of certain species
-These factors determine population sizes of an ecosystem.
-Conditions of arctic regions don’t allow many animals to live there due to the low temperature.
Niches: (all relationships in which species engage in order to survive and reproduce)
-Fundamental Niche is a theoretical niche, where there are no constraints or limited resources)
-Realized Niche is the actual niche, where there are constraints on resources)
Symbiosis: (“living together” Species interacting in +, -, and = ways)
-Both species in interaction benefit
-One species cannot grow/reproduce without another species
EX. Yucca plants are only pollinated by Yucca moths.
-Yucca moths only grow in the yucca plant and only eat Yucca seeds.
-The prey and predator build better defenses and counters to the other’s abilities.
-Since the best of the prey/predator survive more often, they have more chance to reproduce.
-Soon only the strong survive, thus, the best ways of countering reach the entire population.
-EX. Camouflage, Mimicry (faking a characteristic), Spewing toxins, showing teeth, etc
-Maximum number of individuals that resources of environment can maintain.
-Predator-Prey populations can fluctuate.
-Predators may not adjust quickly enough to the abundance of prey.
-Additional predators could also influence the rate.
-As more predators reproduce and eat more prey, the prey population decreases.
-As more prey dies, predators have less to eat and begin to die off.
-With fewer predators, the prey once again starts to reproduce at a faster pace.
Predator- Animals that feed on living organisms, but do not live on them
Prey- targets of predators that are killed
Parasites- Feeds on tissues of living organisms and live on them
Host- the organism a parasite feeds on
Effects of Parasites
-Feeds off the host’s tissue’s nutrition.
-Alters how much energy enters the organism, and weakens it.
-Can alter birth rates, can sterilize, or make organisms less attractive to mates.
-Can open prey to diseases and infections.
-Usually does not want to cause death, so that it can reproduce for a longer period of time
-Rapid reproducers and personally infect the body.
EX. Bacteria, Viruses, Protozoan
-Directly lay their eggs on the host.
EX. Fleas, ticks, mites, lice
-Manipulate the social behavior of another species.
EX. Cuckoos lay their eggs in nests of other species, which push the rightful eggs out.
-The mother of the original eggs ends up feeding the cuckoos.
-Insect larvae that always kill what they eat (larvae and pupae of other insects)
-EX. Wasps give sawfly larvae buried in the ground to their larvae.
-Coevolution keeps both populations in balance. As the sawflies begin to dig deeper and deeper into the ground.
Using Parasites as Control Agents
-Many parasites are raised in order to control the population of certain areas
-5 attributes of good biological controls:
1. Well adapted to a host species and habitat
2. Exceptionally good for searching the host
3. Population growth is higher than the host’s
4. Offspring are mobile enough
5. Able to respond to changes of the host quickly
-Biological controls are risky
-Too many biological controls may be ineffective.
-Biological controls can unexpectedly target the wrong species.
-Populations of different species compete for one resource
-Two species can be similar, but never close as their own species.
-Hence, it is much less fierce than intraspecific competition.
-Some species have better talent to get the resource
-Some species have better access of the resource, and protect it from others
EX. Male broadtailed hummingbird chases other species away from its blossoming territory.
EX. Strangler fig tree wraps around other trees and kills them.
-Two species that require identical resources cannot co-exist indefinitely. However, if their requirements overlap only a little, both could still co-exist with a lower population of each.
-Subdividing the same resource so different species can co-exist.
EX. Plants get, water, sun, and minerals from different parts of the soil.
-One from the top of soil, one from the middle, and one from the bottom.
Type Species 1 Species 2
Neutral 0 0
Commensalism + 0
Mutualism + +
Interspecific - -
Predation + -
Parasitism + -
-A community develops in sequence, from pioneer species to an end array of species, in which new species replace the older species.
-Community stability is the outcome of forces that have come into an uneasy balance. (Not easy)
-First ones to colonize a vacant habitat. (Primary Succession)
-Grow rapidly, have brief life cycles, adapted to exposed sites and deficient soil.
-Dead pioneer species give nutrients to the soil, creating a suitable habitat to other species.
EX. Small grasses, lichens
-The current species stabilizes under the current habitat and reach equilibrium.
-Climax Pattern Model
-Environmental factors vary in influence over different areas, so stable communities other than the final climax stage can also persist in one region.
EX. Tall grass prairie can extend into the deciduous forest.
-Small re-occurring changes can shape many communities.
-Both pioneer species and climax species may be apparent at certain times.
-EX. If a wind blows down a few trees in the forest, light can once again reach the forest grounds. This may allow pioneer species to re-grow (germinate).
-A disturbed area recovers and follows normal ecological succession to the climax species.
-Takes a very long time
-Efforts to reestablish biodiversity in key areas
-Humans can move old species into a barren area to re-establish an old community quicker.
-Disturbances hurt the growth of some populations and can have destabilizing effects
-Can even cause permanent changes to a community or make some species extinct.
-Dominant species that can dictate community structure (species that controls balance of a community)
-Might increases or decrease the biodiversity of a community.
-EX. A Sea Star preys on an assortment of different animals in the intertidal (heavy storms, waves, tides) zone. If the Sea Star is removed, Mussels take over and get rid of a lot of smaller species, since the Sea Star isn’t there to keep the mussels in check. The Sea Star helps less competitive species survive by reducing their predator, the mussel.
-EX 2. Perwinkles eat the dominant algae species in tide pools. However, on rocks at high tide, they leave the predominate predator alone, and eat the weaker algae, decreasing biodiversity in the area.
-A directional movement of species to another community where they successfully establish themselves, and often harm that community
1. Populations slowly expand their homes into surrounding areas.
2. Jump Dispersal
a. Rapid transportation of species across great distances
i. Usually the species cannot survive in the new community.
EX. A coffee shipment from Brazil to Argentina transported some Japanese beetles, which eventually killed native ant species and ground-nesting birds.
EX 2. Many crops are transported from one community to another.
EX 3. Fire Ants accidentally imported from South America into Alabama. The ants make over 70,000 humans seek medical attention.
3. Population might be moved away from its home over geologic time by continental drifts.
Long-term shifts in climate, rapid introduction and successful establishment of a new species can permanently alter a community’s structure.
Mainland + Marine Patterns:
-Biodiversity depends on climate, topographical variation, possibilities for dispersal, and evolutionary history.
-The number of species is always greatest in the tropics and slowly declines when nearing the poles.
1. There are more reliable resources near the tropic areas.
a. Fruit throughout the year
2. With more plant life, there are more herbivores, and co-evolution occurs much more often, since the predator has to adjust to the millions of prey.
a. It is also much easier to resource partitioning if there are more plants already.
3. The rate of new species entering the tropics is larger than the species extinction rate.
-The closer the island is to mainland, the higher amount of species it will have.
-Islands farther away from
-The larger the island, the more species it can contain.
-Larger areas have a more diverse topography and climate, hence can hold more diverse species.
-Larger targets can intercept more species.
-The way living and nonliving things interact through a one-way energy flow and cycling of materials.
-Groups of species in an ecosystem:
Definitions for Ecosystem Species
Trophic Level Purpose Group Definition Examples
1st Primary Producer Photo-autotroph Converts sunlight and carbon dioxide to produce glucose and other nutrients for itself.
1st Primary Producer Chemo-autotroph Bacterium that can make its own organic compounds through carbon dioxide and inorganic substances
2nd Primary Consumer Herbivores Eat species of the 1st trophic level for energy
3rd Secondary Consumers Carnivores Eat species of the 2nd trophic level for energy
4th 3rd level Consumers Carnivores Eat species of the 3rd trophic level for energy
NA NA Omnivores Can eat plants and animals. Belongs in its own trophic level. Fox
NA NA Scavenger Eats both nonliving and living species Vulture
2nd+ Consumers Parasites Feeds on the tissues of living things, and lives on them Ticks
2nd+ Consumers Decomposer Obtains energy from products and wastes of other organisms Fungi
2nd+ Consumers Detrivores Ingests decomposing particles of organic matter Crab
-Depicts the flow of energy through trophic levels
-The more stable environments have longer chains.
-The webs with the most species have the shortest chains.
-The simplest food webs have the most top carnivores.
-Energy starting at the producers doesn’t travel through more than 4 or 5 trophic levels
-The photosynthesizers can only absorb about 1% of the sun’s energy.
-From one trophic level to the next, only about 10% is passed on.
-The other % is either used in metabolic heat, or disposed as waste.
-As one gets higher and higher in the trophic level there is less energy
-Heat that is given off the body to cool itself
-The energy moving through the food webs differ from environment to environment.
-Detrivores generally get most of the net primary productivity (energy)
-They get all the wastes of the grazers, which contain a lot of energy, plus the wastes of producers
-Grazers only feed off the tissues of the trophic level below it.
-The rate at which primary producers store energy in their tissue. (Convert to chemical energy)
-Gross Primary Productivity- Total amount of light energy converted to chemical energy
-Net Primary Productivity- Amount of chemical energy available for the primary consumers
1. How much energy gets stored compared to how much is used for cellular respiration (Conversion from glucose to ATP)
2. Seasonal patterns, type of plant and distribution among the habitat
-EX. The more producers the more energy they can produce. Also, the harsher the climate, the less productive the plants become.
-The bottom of the energy pyramid is always the widest, and drastically shrinks from level to level.
-The sun sends about 1,700,000 kilocalories to the earth, only about 20,810 kilocalories are absorbed.
-Shows the weight of all the members of every trophic level
-Usually the base is the largest since the rest of the community depends on their growth, and they also grow the quickest.
-Biomasses of a pond or sea is usually upside down though
-The Phytoplankton reproduces very fast to support a very large supply of zooplankton
-A slowly degraded substance becomes more and more concentrated in the tissues of organisms as it reaches higher trophic levels. (Such as DDT)
-DDT actually kills the predators of the bugs as well as the bugs.
-Ions or molecules of nutrients transfer from environment -> organism -> environment, in a cycle.
-The nutrients move slowly through the environment, and slowly among the organisms.
-The availability of the nutrients influences the primary productivity of the producers.
1. Usually are mineral elements such as Ammonium.
2. The physical environment and decomposers recycle all the nutrients.
3. The nutrients that cycles through the ecosystems is greater than the amount entering and departing
4. Weather effects often help put more nutrients back into the environment (reserve)
-Typical outputs include erosion from a river.
Hydrologic (water) Cycles:
-Water can help move nutrients throughout the environment
-Water also serves as the electrons for photosynthesis
-Watersheds- any region where precipitation becomes funneled into a single stream
-Water entering a watershed seeps into the soil or becomes surface runoff.
-The losses of nutrients in watersheds are not that big despite erosion.
-The plants normally absorb all the dissolved minerals before they flow through
Ocean > Evaporation > Wind Drives Vapor Over land > Precipitation onto Land > Runoff + Percolation
Land > Evapotranspiration
Percolation- Water seeping into the ground until it reaches the water table
-Evapotranspiration- Evaporation of water from leaves and other plant parts
-Carbon is the backbone of all molecules for living things
-Make up Nucleic Acids, Lipids, Carbohydrates, and Proteins
-Most Carbon is held in sediments, rocks, and oceans.
-Carbon in Ocean is usually Carbonate or Bicarbonate.
-The Ocean removes 2% excess Carbon that is on land.
-Anymore contributes to global warming.
-In rainforests, an organic waste decomposes so rapidly that not much carbon accumulates on the surfaces.
-In bogs, decomposers cannot split apart the small bits, so the carbon is compressed into the soil.
Carbon from burning -> Photosynthesis -> Detrivores + Animals > Atmosphere (Cellular Respiration of Animals)
-Makes up 80% of the earth’s atmosphere
-No species can use Molecular Nitrogen immediately.
N2 -> NH3 (Nitrogen Fixation) -> NH4 (dissolving) ->
NH4 (Ammonification [Residues of NH3 -> NH4)
-Six vast land areas with distinctive kinds of plants and animals
-Large region of land characterized by habitat, community structure, and the species
-Large areas representative of globally important biomes.
-Certain biomes that are the richest in biodiversity
Habitat Descriptions Biotic Life
Desert "Less than 10 cm of annual rain"
"Rain falls in brief, infrequent pulses that swiftly erode the exposed topsoil"
"Humidity is so low that the desert heats up and cools down quickly"
“Many parts of the world are undergoing desertification and turning into deserts themselves” Woody Shrubs
Grasslands “25-100 cm of annual rain”
“Warm temperatures in the summer, extremely cold
in the winter.”
“A lot of grazing and fires”
“Strong winds and infrequent winds, unsuitable for farming” Daisies
Rain Forests “Tall trees grow close together and form a canopy over land
“Over 200 cm of rainfall, Humidity of over 80%”
“Soils are weathered”
Deciduous Forest “Trees lose leaves during dry months, Winters are cold”
Ash, Birch, Chestnut, and Deciduous Oaks
Coniferous Forest “Have cone bearing trees”