Ecology Putting it all together… study of interactions between creatures & their environment, because… Everything is connected to everything else
Ecosystem Living (Biotic) factors all plants & animals living in an area Physical (Abiotic) factors soil, rock, temperature, moisture, sunlight habitat = address (where you live) niche = job (the role you play)
Creatures living in their environment Populations
Level 4 Tertiary consumer SunFood chains Top Feeding relationships carnivore Level 3 Secondary consumer all food chains start with energy from Carnivore the sun Level 2 Primary consumer first level of all food chains is plants Herbivore most food chains Level 1 Producer usually go up only 4 or 5 levels all levels connect to Fungi Decomposers decomposers Bacteria
Loss of energy Loss of energy between levels of food chain To where is the energy lost? The cost of living! 17% growth energy lost toonly this energy daily livingmoves on to the 33% next level in cellular the food chain respiration 50% waste (feces)
Feeding levels How much energy can you get from food? only the energy that is stored in the organism 80-90% energy lost from one level to next food chain can only have 4 or 5 levels
Food webs Food chains are linked together into food webs Who eats whom? eating meat? eating plants? Many connections throughout ecosystem
Energy flows through… secondary loss of consumers energy sun (carnivores) loss of energy primary consumers (herbivores) loss of energy producers (plants)
Food chain pyramid Loss of energy between levels of food chain Numbers can feed fewer animals in each level 1 100 100,000 1,000,000,000
Vegetarians or Meat-eaters?? How many people can Earth support? If we are meat eaters? If we are vegetarian? fewer people can live on Earth more people can live on Earth
But what about nutrients? Energy flows through n u but nutrients cycle t nutrients must be r recycled to be available i e for the next generation n decomposers return t s nutrients to the soil after creatures die fungi decomposers bacteria
Nutrients cycle around… through decomposers consumers decomposers producers phosphorus potassium iron carbon nitrogen calcium soil magnesium
Energy flows Nutrients cycle loss of secondary energy consumers sun (carnivores) decomposers loss of primary consumers energy (herbivores)loss ofenergy producers (plants) 2006- soil
Ecosystem inputs constant input energy flows of energy through nutrients cycleMatterforget Don’t cannotbe created or the laws of destroyed Physics! nutrients inputs can only energy cycle biosphere nutrients
Beneficial Bacteria 99% of bacteria are HELPFUL not harmful! Roles they play in the environment Decomposer Producer Nitrogen fixation Digestion – an example of mutualism too!!
Characteristics of Populations 1. Geographic distribution – area inhabited by a population 2. Density – -number of individuals per unit area. 3. Population growth – populations can increase or decrease in size based on 3 factors: Number of Births Number of Deaths Individuals that enter (immigration) or leave (emigration) a population
Exponential Growth Individuals in a population reproduce at a constant rate Graph = J-shaped curve At first, growth is slow. Over time, growth grows until it reaches an infinitely large size. Occurs under ideal conditions
Logistic Growth As resources become less available, the growth of a population slows Graph = S shaped When does this happen? birth rate slows death rate increases immigration decreases emigration increases Carrying capacity – the largest number of individuals that a given environment can support.
Limiting Factors A factor that causes population growth to decrease 2 Types density dependent density independent
Density Dependent Factors Factor that depends on population size Effect large populations the most Competition – crowded organisms compete with one another for food, water, space, sunlight & other essentials. Predation – one organism captures & feeds on another organism Parasitism & Disease – symbiotic relationship in which one organism lives in or on another organism (the host) and consequently harms it (often causing disease or death)
Density Independent Factors Affect all populations in similar ways, regardless of size Unusual weather Natural disasters Seasonal cycles Some human activities Species will often crash due to one or more of these factors. After the crash some species will recover to build up again, others remain small.
Succession Primary Succession No pre-existing community Secondary Succession Disruption of pre-existing community Climax community Fully mature ecosystem Equilibrium