ecology: the study of ecosystems. organization of life aka biological organization
Post on 02-Jan-2016
225 Views
Preview:
TRANSCRIPT
Ecosystem
• The interaction between organisms and their environment
• The interaction of abiotic and biotic factors
• Can be small (pond, rotting log, local forest, our school) or large (Biomes like tundra, desert, savannah, etc. are super large ecosystems).
Biotic vs. Abiotic Factors
Biotic factors: factors that are or came from a living thing.
Examples: plants, bacteria, fungi, animals, fish, birds, insects, leaves, skin, animal wasteAbiotic factors: factors created by non-living things.
Examples: sunlight, temperature, weather factors, elevation, air, chemicals, minerals, rocks, roads
Trophic Levels (Feeding Levels)
• Producers– Also known as Autotrophs– Make their own food, mostly by photosynthesis. – Most autotrophs are green plants, but some are
microorganisms like bacteria. – They convert the suns energy into chemical
energy. – They are the First Trophic Level.
Trophic Levels
• Consumers– Also called Heterotrophs– Cannot make their own food– Must consume another living thing to get energy– Can be animals, fungi or bacteria – Even a few plants are considered
consumers….the venus fly trap plant “eats” insects
Types of Consumers
• Herbivore – animal that eats plants (ex. deer)• Carnivore – animal that eats animals (ex. lion)• Omnivore – animal that eats both plants and animals• Detritivore – animal that eats dead organisms or their wastes
(detritis). They are also called scavengers (ex. vulture) • Decomposer/Saprotroph – break down dead
organisms/animal wastes and return/recycle nutrients to the ecosystem
• Ex. Fungi, Bacteria, or Detritivores• A type of consumer
Some other terms to know
• Nutrients: Substances that are required by an organism for its normal functioning, growth and repair. Nutrients include fats, carbohydrates, proteins, vitamins, minerals and water as well as the elements that they are composed of.
• Organic: matter that contains the element carbon. All living things contain this element and therefore living things are organic matter.
• Inorganic: matter that does not contain the element carbon. For example, water does not contain carbon atoms and is therefore an inorganic substance. (H20)
Video• Watch Bill Nye’s “Food Webs” and answer the
questions on the worksheet (just first 13 min)
http://www.youtube.com/watch?v=sVB82laAJl0&safe=active
Energy in Ecosystems
• Ultimately, the source of all energy in ecosystems is the sun
• Producers convert the sun’s energy to food energy
• Consumers eat plants or they eat animals that ate plants
Energy Flow in Ecosystems
• Energy flow is one way – from the sun to plants to animals
• The energy used by living organisms is either used up for their life activities or it is lost along the way as heat
• Energy does not cycle (lost energy or heat from ecosystems does not return to the sun)
The Cow eats grass. Some of the energy from grass goes into making new cow tissue, but lots of the energy (90%) is lost as heat, during respiration or as urine and feces
Grass
Thermodynamics
Definition – the study of how energy is transferred
1st Law – energy is conserved; it is not created or destroyed
2nd Law – every time there is an energy transfer, some energy is lost along the way
Ecological Pyramids
• Used to show the energy available at each trophic level
• There are 3 types:
– Pyramid of Energy– Pyramid of Biomass– Pyramid of Numbers
Pyramid of Energy
Only 10% of the energy from a trophic level is available to the next trophic level – called the 10% rule
Why Food Chains aren’t longer
The 90% loss of energy at each trophic level explains why there can’t be more than 5 trophic levels. By the time quaternary consumers get to eat, there just isn’t much energy left.
Worksheet Answers
1) Decreases2) 10%3) Heat, Respiration, Wastes4) 2nd 5) Energy emitted from the sun never returns
back to the sun6) Dry weight/mass of living things7) Biomass = dry mass; Numbers = actual counts
8) Because there is a 90% loss of energy/biomass at each step, so by the time tertiary or quaternary consumers get to eat, there isnt much food left
9) There has to be more herbivores than carnivores because there has to be more energy at the trophic level that is being fed on than in the one doing the eating because of how much energy is lost between levels.
10) The trophic level above always has less energy compared to the one below it.
BONUS QUESTION• Ecologically friendly - More food to feed more
people (10 x more). Human population is increasing so need enough food for all. Less land is needed to raising plants compared to raising animals.
• Healthier – less toxins(less biomagnification) and less bad fats from meat.
1 Human
10 Chickens
100 Corn
10 Humans
100 Corn
top related