Introduction

• Global climate patterns are largely determined by the input of solar energy and Earth’s revolution around the sun

• The changing angle of the sun over the year, bodies of water, and mountains exert seasonal, regional, and local effects on climate

• Climate effects where plants can live, but these effects run both ways: vegetation can alter local and regional climate 

• Fine scale differences in abiotic (nonliving factors) such as sunlight and temperature

• Increased greenhouse gasses warm the earth and disturb species 

Global warming

• The climatic change phenomenon by which atoms of certain gaseous molecules are held together in the Earth’s atmosphere, where they trap heat and release radiations

• Causes - industrialization, oil drilling, deforestation, power plants, higher livestock farming, greenhouse effect

• Preventions, reducing fossil fuel waste, planting trees

Ice sheets

• Dome shaped, slow movement downhill, behaving like a liquid

Positive feedback loop

• Climate change is rapidly occurring

• Areas with frozen ice reflect sunlight 

• The planet is becoming hotter due to more sunlight absorption by water and dark colored ground

•  it causes a positive feedback loop and more melting ice due to warming of the environment 

• Global warming leads to loss of sea ice, more sunlight is absorbed by ocean water, sunlight warms the water and the air above it, contributing to more sea ice loss

Latitudinal diversity is considered a reason behind a greater habitat diversity at the equator. creates specific areas and niches for species to inhabit

• Increasingly experimental

•  field studies

•  Holistic  approach

•  Multidisciplinary

•  political and legal issues

 Top five ecological issues

• H Habitat destruction

•  I introduced species

•  Pollution

•  P  population growth

•  o over consumption

interactions between organisms and environment determine distribution and abundance 

Special limit distribution?

•  no cicadas in West because barrier, food, no females deposit on deciduous trees

•  predators, pesticides, tree removal, weather

• underground 17 years because climate / predators

• Cue to emerge not understood

  • Temperature, time of day, soil nutrients - biotic and abiotic to reproduction

Semelparity - High number of reproduction

Behavioral ecology - nature versus nurture

Chapter 54 (Campbell’s Biology Textbook)

Community Ecology Interactions

Competition

• Competition exclusion principle

  • Cannot coexist at constant populations / one more likely to be more successful

  • Two species can not occupy the same ecological niche

    • Niche - a place or position that's particularly appropriate for someone or something, especially due to being very specific and different from others

• Niche (Fundamental, realized)

• Resource partitioning (not competing)

• Character displacement 

Photo 

Intraspecific 

• Fighting over a common desire/need

• Practice resource partitioning to prevent competition for common needs 

Competitive Exclusion vs resource partitioning

• Competitive exclusion

  • Principle tells us that two species cant have exactly the same niche in a habitat and stably coexist

  • Does not support the coexistence of two species competing for identical resources

• Resource partitioning

  • The division of the niche by species to avoid competition for resources

  • Helps the species to coexist since it creates less direct competition between them 

• Allopatric population = geographic isolation

• Sympatric population = reproductive isolation (evolved from a single ancestor) “S” Same area

Allopatric

• Geographic isolation = different niches -> speciation

Energetic Hypothesis

• Length of food chain limited

• Only 10% of energy stored is converted to the next level

Dynamic Stability Hypothesis

• Long food chain less stable than short food chain

• Possible local extinction of top predator 

Keystone Species

• A species that if were to be removed would cause the entire ecosystem to collapse

Robert Paine Keystone Species Concept

The sea star Piaster ochraceous living in Mukkaw Bay, Washington, feeds on mussels

When Pisaster ochraceus was removed the mussel population increased and the number of other species decreased

• With the top predator gone, the next strongest will take over the ecosystem, It can cause an ecosystem to fail. 

Predation (+,-)

• Definition: the preying of one animal on others

• Behavioral defense

  • Flight, freeze

• Morphological defense

  • Having armor or spines

    • Daphnia, porcupine, lionfish and breast cancer cell

• Cryptic coloration

  • Camouflage, making prey difficult to see

    • Eastern screech owl, gumleaf grasshopper, leaf insect 

• Aposematic Coloration

  • Warning/aposematic coloration (advertise that an organism is dangerous or unpalatable)

    • examples: poison dart frog, Nudibranchs, Blue-ringed Octopus (only shows rings when threatened)

  • Cryptic coloration 

    • Examples: Canyon tree frog

  • Batesian mimicry: A harmless species mimics a harmful one

• What’s the difference between mimicry and camouflage?

  • Mimicry, an organism copies another organism or part of an organism, while camouflage involves the copying of some part of the environment.

  • Müllerian mimicry – two or more unpalatable species resemble each other.

    • examples: cuckoo bee and yellow jacket

  • Batesian mimicry – a palatable species or harmless species mimics an unpalatable or harmful species (not closely related)

    • example: hawkmoth larva resembling venomous snake

Herbivory

• Adaptations for herbivore (teeth, digestive system) grazers-browsers

• Plant defenses

  • Mechanical (thorns)

  • Chemical (toxins)

Chemical defenses in plants

• Caterpillars ingest milkweed

Symbiosis

• Mutualism (+,+)

  • Definition: symbiosis that is beneficial to both organisms involved.

    • Lichen (algae and fungus) Housing + nutrients

• Commensalism (+,0) 

  • Definition: an association between two organisms in which one benefits and the other derives neither benefit nor harm.

    • Cattle egret benefits from water buffalo when they walk through the plains

• Parasitism (+, - )

  • Definition: the practice of living as a parasite in or on another organism.

  • Parasitic wasp eggs on a caterpillar

Intermediate disturbance hypothesis

• At low disturbance, competitive exclusion reduces diversity

• At high disturbance levels, diversity declines as mortality rises

• At intermediate disturbance levels, a balance between disruption or competition and morality leads to high diversity

• Foster greater species diversity 

Describe how disturbances have an effect on ecology

Types of disturbances and their frequency and severity very among communities

 storms, oceans, fire, streams

 a high level of disturbance is generally the result of frequent and intense disturbance, while low disturbance levels can result from either a low frequency or low intensity of disturbance 

The intermediate disturbance hypothesis states that moderate levels of disturbance Foster greater species diversity then do high or low levels of disturbance.

•  high levels of disturbance reduce diversity by creating environmental stresses that exceed the tolerances of many species or by disturbing the community so often that slow growing or slow colonizing species are excluded

•  low levels of disturbance can reduce species diversity by allowing competitively dominant species to exclude less competitive ones

•  intermediate levels of disturbance can foster greater species diversity by opening up habitats for occupation by less competitive species

Supported by many terrestrials and Aquatic studies

•  ecologists in New England compared to the richness of invertebrates living in the beds of streams exposed to different frequencies and intensities of flooding

  •  when floods occurred either very frequently or rarely, and vertebrate richness was low

  •  frequent floods made it difficult for some species to become established in the Steam bed, while rare floods resulted in species being displaced by Superior competitors

 small and large disturbances also can have important effects on community structure

•  small-scale disturbances can create patches of different habitats across the landscape,  which  help maintain diversity in a community

  •  much of Yellowstone National Park is dominated by logical pine, a species that requires the rejuvenating influence of periodic fires

    • The fire releases the seeds and pine cones to reproduce

Chapter 55 (Campbell’s Biology Textbook)

Ecosystems

Themes

• Energy flow

• Production (GPP/NPP)

• Nutrient cycles

• Human impact

Trophic Relationships

• Autotroph/producer

• Heterotroph/consumer

  • Primary-herbivore, secondary-carnivore

• Detritivores - feed on detritus-heterotrophic

• Food chains-only 3-4 links (why?)

  • We lose energy as it is consumed

Primary productivity

• Amount of light energy -> chemical energy (organic compounds)

• Measured in joules (200J = 47 calories)

• Gpp - R_a = NPP

  • Gross primary productivity - Autotrophic respiration = On average about half of GPP

    • Energy stored during photosynthesis - Energy for cellular work = Energy stored as biomass

• Net Primary Production is increased with excess moisture and high temperature 

  • Think of the equator and the NPP in regions in the equator

Primary Production Limitations

• Aquatic ecosystems

  • Light, nutrients (nitrogen and phosphorus taken up very fast)

    • Algae blooms/hypoxia

  • Availability of iron can limit pp

  • Eutrophication (excess)

• Terrestrial ecosystems

  • Temperature, moisture

  • Human impact - farming

Secondary production

• Consumed and made into new biomass (the mass or weight of living tissue)

• Energy flows (materials cycle)

• Loss of energy with each transfer

• Mammals productivity low (1-3) why?

  • Use energy to maintain high body temps 

• Coprophagy - Obtain bacteria for digestion, absorption of vitamins and minerals

Bioaccumulation

• How toxins enter the food chain

• Pollutants/chemicals

  • Long-lived (long .5 life)

  • Fat-soluble

  • Fattest tissue in the human body? 

    • Brain (breasts in women)

Biomagnification

• Toxins are more concentrated in successive trophic levels

• DDT (Shell Thinning-raptors)

  • Dichlorodiphenyltrichloroethane

• Mercury poisoning (fish)

PCBs in fish

• Polychlorinated biphenyls

Nutrient cycles

• Carbon cycle

  • CO₂  in atmosphere used for  photosynthesis 

  • Importance

    • Organic molecules must have carbon

• Nitrogen cycle

  • Symbiotic relationships 

  • Nitrates - most usable

  • Nitrites

  • Importance of

    • We need nitrogen for life, important for amino acids and proteins

    • DNA/RNA

• Phosphorus cycle

  • DNA/RNA

  • ATP

  • Cell membrane (phospholipid)

• Water cycle

  • Precipitation, evaporation, transpiration 

Blue Baby Syndrome

• Methemoglobinemia

  • High nitrate contamination in groundwater (food used with water)

  • Leaching of nitrate from fertilizer (agricultural lands and waste dumps)

• Bacteria (infants gut) produce nitrites 

• Nitrite reacts with hemoglobin -> methemoglobin

• Level of O₂ decreases

• The baby suffocates 

• 3 months - increase in HCL kills most of the bacteria that convert nitrate to nitrite 

• 6 months - none of the nitrate-converting bacteria remain