XMind

Ecology

1. Populations

   1. Plant population

      1. Distribution Patterns

         1. Dominant, Abundant, Frequent, Occasional, Rare, Non Existant

      2. Biomass - Weight of material present in area (Timber)

      3. Cover (%) - Estimate of ground covering

      4. Frequency (%) - Present/Absent. If found in 20 out of 50 Quadrats (20/50x100=40%)

      5. Density - No. per unit area (Quadrat)

   2. Logistic growth

      1. S Shaped curve

         1. dN/dt = rN(1-N/k)

   3. Current population present = N

      1. J Shaped Curve

      2. Capacity to increase (birth - death = biotic potential = r

         1. Rate of change (dN/dt)

            1. dN/dt = r x N = rN

   4. Metapopulations - network of populations with movement between

   5. A group of similar organisms in a place

      1. Usually constant but can change

         1. Nt+1 = Nt+B+I-D-E

            1. Death & Emigration

               1. Lack of resources

               2. Loss of population

            2. Birth & Immigration

               1. Gain in population

   6. Hard to count

      1. Tag Birds/Roadside counts

   7. Organisms don't exist in isolation

      1. Safer in groups

      2. Can't reproduce

2. Communities

   1. Only concerns organisms

   2. Patterns within Communities

   3. Keystone Species (Critical to persistance of community)

   4. Structure - Species Richness, types of species, relative abundance

   5. Chemosynthesis is another way for primary production. Deep at see hydrothermal vents

   6. Studied by Mapping food flow between trophic levels.

      1. 10% of energy passed from one trophic level to the next

   7. Not stable

   8. Function - Energy flow (Carbon), Productivity

   9. Biomes - geographical zones based on dominant vegetation & climate

   10. Collections of Species in a common environment/habitat

       1. Interact in the same place at the same time

3. Succession

   1. Secondary Succession

      1. Seed bank is left intact

      2. Return to natural vegetation from a disturbance.

   2. Primary Succession

      1. In new habitats previously not colonised

      2. Initial colonists depend on substrate

         1. Smooth Rock = Lichens

         2. Rough Rock = Mosses

         3. Block Scree = Some trees/ferns

         4. Sand = Grasses

      3. Animals: Develop soil structure, drainage, nutrients, fertility. Seed despersal.

      4. Models of Succession

         1. Facillitation: early species are adapted, suitable for succession

         2. Inhibition: Species that first inhabit the area and disturb it allows others to succeed.

         3. Tolarance: early conditions are suitable for species to grow but speed at which they colonise is essential

      5. Nitrogen Fixing

         1. Some plants have a symbiotic relationship with Nitrogen Fixing fungi

      6. Plants need: Anchorage, Water, Oxygen, Nutrients (Nitrogen, Phosphurus, others)

      7. In areas where geographical disturbance occurs (Volcano, Sand Dunes, Glacial retreat)

      8. Begins without seed bank in soil

   3. Climax Pattern, Most recognised

      1. Open system. Continuum of communities, linked to environmental differences

   4. In undisturbed habitats, change will be slow

      1. Soil --> Grass --> Shrubs --> Trees --> Large Trees

      2. Bare Soil -----> Broad leaved woodland

   5. Progression of vegetation through time. Slow process. Final stage is Climax Community.

      1. Climax Communities - Linear process, deemed to be stable

   6. Changes in communities after time

      1. Natural, gradual change in species that live in an area. May relate too dominant species or disturbances

      2. Usually plants

4. Predation & Herbivory

   1. Predation ( + - )

      1. Lotka–Volterra system

         1. Co-evolutionary arms race

      2. One organism eats all or part of another

      3. Group living

         1. safety, reproduction, distractions

   2. Herbivory

      1. Eat plants, fruits, seeds

      2. eat all or part of plant

      3. Metabolic feeders: eat the inside of plants

      4. Tissue Feeders: eat actual parts of plant (branches, leaves)

      5. Plants can use chemicals to defend themselves

5. Soil Ecology

   1. Soil Types

      1. Brown Earths

      2. Podzols

      3. Gleys

   2. Soil Sampling

      1. Pitfall trap: Dig hole, collect things that fall into it

      2. Soil Auger (Core sample)

      3. Tullgren Funnel (Draws animals out of soil)

      4. Hard to sample without destroying area

   3. Soil Organisms

      1. Time spent in soil (temporary, periodic, perminant, transient)

      2. Classified by size (Megafauna etc)

   4. Pedosphere

      1. Biosphere (1-10%)

      2. Hydrosphere (25%)

      3. Atmosphere ( 25%)

      4. Lithosphere (45%)

   5. Soil Zone

      1. Litter Zone

         1. Attracts detritivores as it gains litter

      2. Rhizosphere (Root Zone)

         1. Micro-organisms found

         2. Plants get water & nutrients

         3. Plant-Microbe interactions occur

6. Ecology

   1. Abundance and Distribution

   2. Organisms, Population, Community, Ecosystems, Biome, Biosphere

   3. Individuals/Groups of species in habitats

   4. Symbiosis: living together

   5. Interatctions of Species

   6. k Selected

      1. City dwellers, logistic model (S Shaped curve), larger, long lives, breed several times

   7. r Selected

      1. Colonists, Geometric Model, Small, Short Lives, Breed once then die

7. Autecology

   1. R/k Selected

      1. Limit on k selected growth

   2. Vertibrae/Invertibrae

   3. Age - Tree rings, fish scales

   4. Ecology of one Species

   5. Synecology - Group of Species

8. Competition and Symbiosis (The Niche)

   1. Two or more species can interact

   2. Organisms don't live alone, they interact

   3. The Niche

      1. Necessary in the study of competition in Ecology

         1. Niches are multi-dimensional: they have many influencing factors (water, temperature etc)

            1. Each species has it's own unique niche

      2. Taxonomic Heirarchy

      3. Adaptive Radiation: Diversification of an ancesteral group of organisms into a variety of niches

      4. Competitive Niche, species can broaden their niche

      5. Competitive Exclusion: if two species need the same resource and they have the same/similar niche, one will drive the other to extinction

      6. Realised Niche: The role that an organism plays in the community

      7. Fundamental Niche: The niche that an organism would occupy in the absense of competetors/predators

         1. To keep a species alive, all the factors of the fundamental niche must be met.

      8. "The Precise way in which a species fits into the environment"

   4. Mechanisms for Interaction

      1. Competition

         1. "an interaction by individuals brought about by a shared requirement for a resource in limited supply"

         2. Exploitative Competition: utilize a common resource that is in short supply

         3. Interfearence competition: one prevents another from competing by physically stopping it

         4. Inter-Specific: Members of different species

         5. Intra-Specific: Members of the same Species

            1. Reduces growth, decreased survival, decreased reproduction

      2. Predation

      3. Herbivory

      4. Disease (Pathogenic Micro-Organisms)

      5. Symbiosis

         1. Parasitism

            1. Ectoparasite: Outside host

            2. Endoparasite: inside host

         2. Mutualism

            1. Obligitary: One can't exist without the other

            2. Facultative: can live seperately but benefit each other

         3. Commensalism

            1. One benefits, the other has no effect

         4. Effects

9. Ecosystems (Biocoenosis)

   1. Abiotic Environment

      1. Topography: Shape of land

         1. North/South Facing

         2. Altitude/Amount of Oxygen

         3. Water Pressure

      2. Seasons

         1. Light intensities

      3. Geology and soil

         1. Rock types have a large influence on plant distrubution

         2. Soil as a function

   2. Biotic Environment

      1. Carbon cycle

      2. Ecosystem Engineers: Lumbricus terrestris

         1. Change the ecosystems in which they live

      3. Mineralization: Conversion of elements in an organic form to an inorganic form. Decomposition.

      4. Nitrogen fixing

         1. Rhizobium (Symbiosis)

   3. Climate & Weather

   4. Migration/Hibernation

   5. Many communities & the environment

   6. Biotic and Abiotic parts together

   7. Trophic pyramids

10. Evolution & Natural Selection

    1. Biological evolution

       1. Develops simple organisms into complex ones

       2. Learning about new strata

       3. Realization of length of process

       4. Increases species number and variation

       5. Gradual change in population which makes it more suitable to the environment

    2. Darwinian Evolution

       1. Went to Galapogas Islands

          1. Slight variations in finch species

       2. Variation in offspring from parents

          1. Some characteristics will hep them survive better than others

       3. Evolution by natural selection

          1. Will favor traits that suite the environment best

          2. More individuals are produced than can survive

          3. Individuals show variations

             1. Some variations hereditory, others completely different

          4. Selection process filters out those who are less well adapted

             1. Genotypes and Pheonotypes

             2. Those best designed, survive.

             3. Poorly designed die out

             4. Remaining Individuals will create offspring similar to them

             5. Each generation will develop and become more and more complex

    3. Pax 6 is master gene for eyes

    4. Covergent Evolution: Species don't need to be related to share the same adaptaions/designs They may share the same environmental pressures.

    5. Mechanisms for Species to arise

       1. Sympatric: Population --> Part becomes isolated --> becomes two species.

       2. Parapatric: Population not sperarated but extremes become so extreme they become reproductively isolated as two different groups.

       3. Allopatric: Population geographically split so they become reproductively isolated. This is slow

    6. Species are hard to define

       1. (a) A population that is reproductively isolated

       2. (b) If fertile offspring can be produced

    7. Asexual Reproduction

       1. In Sexual reproduction, each parent passes half genes each

       2. Uncommon due to lack of variation, all clones

       3. Macroevolution Microevolution

       4. In asexual reproduction, an identical clone is created from the parent

          1. Budding (Grown out of parent)

          2. Parthenogenesis: unfertilized egg is laid, no fertilization is needed

          3. Fragmentation: bits of body break off and grow

          4. Passes genes on effectively

          5. Ability to produce lots of offspring

    8. "A gradual process in which something changes into a different and often more complex form"

       1. Floating Topic