Ch 6: Ecosystems

• Disease ecology: effects of host-pathogen interactions
• Productivity: source of energy for all species emerges from autotrophs that get their energy from the sun
• Energy flow: movement of energy through the ecosystem
• Food chain: linear depiction of energy flow
• Each feeding level in a chain is a trophic level
• Relationships are interconnected so a food web is more correct
• Trophic-level transfer is described as the amount of energy at one trophic level that is acquired by the trophic level above and incorporated into biomass
• Average of 10% loss between levels
• Some marine food chains experience a 30% loss between levels
• Trophic-level transfer efficiency is low for two reasons: 1) Many organisms can't digest all of their prey 2) Much assimilated energy is lost as heat (warm blooded animals burn a lot of energy)
• Trophic-level transfer efficiency limits the number of trophic levels in a food web
• Think about your ecological footprint: it takes a lot less energy to make a salad compared to steak
• DDT is a fat soluble molecule that is stuck in all the food that we eat
• When pesticides accumulate in organisms they then are magnified at every trophic level
• What is the safest trophic level to eat?

  Anything that doesn't have fat cells, producers
• Polar vortex: A large area of low pressure that moves across the northern hemisphere in winter due to melting ice caps
• Climate change focuses on rates of CO2 production, it is not slowing down
• Solar energy is not proof for climate change since they are not related, it is often used though
• Burning fossil fuel produces CO2 that is directly related to climate change
• There are natural cycles of temperature but we are at much higher projected levels right now
• High temperature changes can alter the sex that is produced in some amphibians/animals
• Warm temperatures melt ice causing sea levels to rise and cause a loss of land
• CO2 dissolves in the ocean to make carbonic acid and lower the pH
• A lower pH in the ocean disrupts the entire marine food web