Topic 5 - On the Wild Side

• Abiotic factors include:

  • Soil pH
  • Temperature
  • Humidity
  • Mineral composition of soil
  • Salinity of water
• Some biotic factors include:

  • Disease
  • Predators
  • Availability of food
  • Competition
• Pioneer species such as lichens, mosses, and algae, begin to break up the rock and form a very thin soil
• First plant species in succession are quick-growing grasses and ferns that tolerate poor soil, when they die they will help to build better soil
• Flowering plants (herbaceous) such as dandelions are 3rd in succession, they take nitrogen from the air and bring it into the soil
• Climax community is the final stage of succession, it's a stable community with a complex foodweb formed by succession over time
• Primary succession is going from bare rock after an event like a retreating glacier, volcanic eruption or erosion, taking up to thousands of years to reach climax community
• Secondary is succession is when succession starts from soil rather than bare rock, this may only take 10 years
• Peat bogs are anaerobic and slightly acidic
• We can use peat bogs to find out about climates:

  • Plants produce pollen that's individual to that plant
  • Pollen has a touch outer layer and peat is very good at preserving
  • Peat forms in layers, the older the deeper
  • Each plant species flourished in different conditions
• Dendrochronology is studying the climate by looking at the rings inside a tree:

  • Each year a new layer of xylem forms
  • Vessels are narrower when dry and cold, wider when wet and warm
  • Taking a core sample and counting the rings, tells you how old it is
• Ice core samples are similar to peat bogs:

  • They come from glaciers with permafrost
  • Each year when rainfall freezes a new layer is formed
  • We can use O2 isotopes, CO2 concentration, CH4 concentration and dust content to date the cores
• Methane is produced by anaerobic decay in waterlogged conditions as well as decay of household waste. It is also produced in the digestive systems of cattle and incomplete combustion of fossil fuels]
• Making mathematical models includes the extrapolation of data and ignoring fluctuations
• Mathematical models may be wrong is present trends change, many factors must be taken into account
• Anthropogenic means caused by humans
• Topography is the altitude, slope, aspect, and drainage of a landscape
• Different producers store different amounts of energy, this is called primary productivity
• Net productivity = Gross productivity - respiration
• Net productivity is the amount of energy available for the next trophic level
• Not all solar energy will be taken in by producers as some may reflect off of the leaves or may miss the plant
• Energy transfer=energy available after transfer/energy available before transfer x 100
• Darwin's initial observations:

  • Organisms produce large numbers of offspring
  • No two organisms are identical, variation in characteristics of members of the same species
  • Offspring generally look like their parents - characteristics can be passed on
  • Individuals better adapted to their environment are more likely to survive
• Natural selection:

  1. Random mutations give rise to potentially advantageous alleles
  2. Environmental factors determine which individuals of a species survive (selection pressures)
  3. Advantageous adaptations will be selected for, those individuals are more likely to survive and breed, passing on their alleles
  4. The advantageous allele frequency will increase over time
• A predator is an animal that hunts and kills animals for food
• Prey is an animal that gets hunted and killed for food
• A scavenger is an animal that eats dead animals but doesn't kill them
• Detritus is dead and waste matter that doesn't get eaten by consumers
• A decomposer is an organism that consumes detritus]
• A detrivore is an animal that eats detritus
• A saprophyte is a microbe that lives on detritus
• Symbiosis is organisms living together in a close relationship
• Mutualism is two organisms living together for a mutual benefit
• Commensalism is a relationship in which only one organism benefits
• A Parasite is an organism that feeds on a larger living host organism, harming it
• A pathogen is a microbe that causes disease
• A producer is an organism that produces food from carbon dioxide and water using photosynthesis. Can be a plant, algae, plankton, or bacteria
• A consumer is an animal that eats other organisms
• A herbivore is a consumer that eats plants (primary consumer)
• A carnivore is a consumer that eats other animals (secondary consumer)