What is Ecology ? What is Ecology ?

Population Population = Group of same species living in same area Population = Group of same species living in same area Individuals in a population have a high likelihood of interacting and breeding with one another Individuals in a population have a high likelihood of interacting and breeding with one another

Population Growth Exponential Exponential Logistic w/ Carrying Capacity Logistic w/ Carrying Capacity

Factors the Affect Population Growth: Density Dept vs Indept Density Independent Density Independent - Climate Density Dept Density Dept the buildup of toxic wastes the buildup of toxic wastes Limited food supply Limited food supply increased disease increased disease predation predation

Community Community: all populations in a given area Community: all populations in a given area

Community: Niche & Competition A population's niche = role in the community A population's niche = role in the community The sum total of its use of the biotic and abiotic resources of its habitat The sum total of its use of the biotic and abiotic resources of its habitat

Community: Competitive Exclusion Principle Populations of two species cannot coexist in a community if their niches are nearly identical Populations of two species cannot coexist in a community if their niches are nearly identical Leads to either: Leads to either: Competition & death of one Competition & death of one Natural Selection & resource partitioning Natural Selection & resource partitioning

Community: Competition & Resource Partitioning

Community: Symbiosis Symbiosis: interaction between two or more species that live together in direct contact Symbiosis: interaction between two or more species that live together in direct contact Three types: Three types: Mutualism Mutualism Commensalism Commensalism Parasitism Parasitism

Community: Mutualism Symbiosis Both benefit Both benefit Ex. Ex. Nitrogen-fixing bacteria and legumes Nitrogen-fixing bacteria and legumes

Community: Commensalism Symbiosis Commensalism = one benefits, the other is unaffected Commensalism = one benefits, the other is unaffected Not as common Not as common Ex Ex Algae that grow on the shells of sea turtles Algae that grow on the shells of sea turtles Barnacles that attach to whales Barnacles that attach to whales Birds that feed on insects flushed out of the grass by grazing cattle Birds that feed on insects flushed out of the grass by grazing cattle

Community: Commensalism Parasitism One benefits while other harmed One benefits while other harmed

Community: Predator / Prey Predator: consumer Predator: consumer Prey: food species Prey: food species

Community: Predator / Prey Coevolution Coevolution: as predators adapt to prey, sometimes natural selection also shapes the prey's defenses Coevolution: as predators adapt to prey, sometimes natural selection also shapes the prey's defenses

Community: Prey Defenses Mechanical Defenses (quill of porcupine) Mechanical Defenses (quill of porcupine) Chemical Defenses (poison frog) Chemical Defenses (poison frog) Camouflage Camouflage

Community: Prey Defenses Mimicry Batesian – harmless mimicking harmful Batesian – harmless mimicking harmful Mullerian – both harmful Mullerian – both harmful

Community: Ecological Succession Ecological Succession: transition in the species composition of a community following a disturbance Ecological Succession: transition in the species composition of a community following a disturbance Primary vs Secondary Primary vs Secondary Primary succession: gradual colonization of barren rocks by living organisms, starting with Pioneer organisms Primary succession: gradual colonization of barren rocks by living organisms, starting with Pioneer organisms

Community: Ecological Succession PrimarySecondary: after disturbance

Ecosystem: Energy Flow & Chemical Cycles Ecosystem = Community + abiotic factors in habitat Ecosystem = Community + abiotic factors in habitat Two things needed in ecosystem: Two things needed in ecosystem: ENERGY: flows from the sun, through plants, animals, and decomposers, and is lost as heat ENERGY: flows from the sun, through plants, animals, and decomposers, and is lost as heat CHEMICALS: recycled between air, water, soil, and organisms CHEMICALS: recycled between air, water, soil, and organisms

Ecosystem: Energy Flow & Chemical Cycle

Ecosystem: Energy, Food Chain Food chain = flow of energy and nutrients Food chain = flow of energy and nutrients from plants (producers) from plants (producers) to herbivores (primary consumers) to herbivores (primary consumers) to carnivores (secondary and higher- level consumers) to carnivores (secondary and higher- level consumers)

Ecosystem: Food Chain, Decomposers Detritivores decompose waste matter – detritus (break down organic molecules) and recycle nutrients (into inorganic) Detritivores decompose waste matter – detritus (break down organic molecules) and recycle nutrients (into inorganic) Examples: animal scavengers, fungi, and prokaryotes Examples: animal scavengers, fungi, and prokaryotes

Ecosystem: Energy Food Web

Ecosystem: Energy Pyramid Only ~10% of energy in food of each trophic level is available to the next level - rest used or lost as heat Only ~10% of energy in food of each trophic level is available to the next level - rest used or lost as heat

Ecosystem: Biomass Pyramid Biomass = amount of living organic material in an ecosystem Biomass = amount of living organic material in an ecosystem Based on Primary production = rate at which producers convert sunlight to chemical energy Based on Primary production = rate at which producers convert sunlight to chemical energy

Ecosystem: Chemical / Nutrient Cycles Water Cycle Water Cycle Carbon Cycle Carbon Cycle Nitrogen Cycle Nitrogen Cycle

Ecosystem: Water Cycle

Ecosystem: Carbon Cycle Carbon needed to make organic molecules Carbon needed to make organic molecules Carbon fixation (photosynthesis) : inorganic carbon (CO2) into organic compound (sugar) Carbon fixation (photosynthesis) : inorganic carbon (CO2) into organic compound (sugar)

Ecosystem: Nitrogen Cycle Nitrogen plentiful in atmosphere as N 2 Nitrogen plentiful in atmosphere as N 2 But plants cannot use N 2 But plants cannot use N 2 Bacteria in soil (and legume root nodules) convert N 2 to nitrogen compounds that plants can use Bacteria in soil (and legume root nodules) convert N 2 to nitrogen compounds that plants can use Ammonium (NH 4 + ) and nitrate (NO 3 – ) Ammonium (NH 4 + ) and nitrate (NO 3 – )

Ecosystem: Nitrogen Cycle Nitrogen Fixation (Nitrogen fixing bacteria): convert N 2 gas into Ammonium NH 4 Nitrogen Fixation (Nitrogen fixing bacteria): convert N 2 gas into Ammonium NH 4 Nitrification (Nitrifying bacteria): convert NH 4 into Nitrates NO 3 Nitrification (Nitrifying bacteria): convert NH 4 into Nitrates NO 3 Denitrification (Denitrifying bacteria): convert NO 3 into N 2 gas Denitrification (Denitrifying bacteria): convert NO 3 into N 2 gas

Ecosystem: Nitrogen Cycle

Terrestrial Biomes

Biomes: Tundra Treeless artic tundra, permafrost (soil) Treeless artic tundra, permafrost (soil) Cold, wind, lichen Cold, wind, lichen

Biomes: Tiaga Cold, coniferous forest Cold, coniferous forest Largest terrestrial biome (land-wise) Largest terrestrial biome (land-wise) Long winter, short wet summer Long winter, short wet summer

Biomes: Temperate Deciduous Forest sufficient moisture to support the growth of large trees sufficient moisture to support the growth of large trees

Biomes: Savanna Drier, tropical areas and some nontropical Drier, tropical areas and some nontropical

Biomes: Temperate Grasslands Temperate grasslands are found in the interiors of the continents, where winters are cold Temperate grasslands are found in the interiors of the continents, where winters are cold Drought, fires, and grazing animals prevent trees from growing Drought, fires, and grazing animals prevent trees from growing

Biomes: Desert Deserts are the driest of all terrestrial biomes Deserts are the driest of all terrestrial biomes Characterized by low and unpredictable rainfall Characterized by low and unpredictable rainfall

Biomes: Tropical Rain Forest Tropical rain forest = most diverse Tropical rain forest = most diverse

Biomes: Marine Aquatic Oceans cover about 75% of the Earth's surface Oceans cover about 75% of the Earth's surface

Biomes: Marine Aquatics Estuaries = productive areas where rivers meet the ocean Estuaries = productive areas where rivers meet the ocean They provide nursery areas for oysters, crabs, and many fishes They are often bordered by extensive coastal wetlands They are often bordered by extensive coastal wetlands