Chapter 2. Patterns of Association
Spatial distribution
Pelagic = organisms found in water column Benthic = Organisms found on/in/near sea floor
Evolutionary relationships and Taxonomy
Taxonomy and classification
Evolutionary adaptions
5 types of living organisms
All organism are capable of ecological and evolutionary adaption
Trophic relationships
Food chains and food webs
Harvesting energy
Living creatures need two things: matter to repair, grow and reproduce; and energy (ATP).
Materials cycle and energy only goes in one direction (sun - autotrophs - consumers - decomposers)
General nature of marine life
Marine life exists within a dense, circulation, interconnecting seawater medium
Epifaunal = Benthic organisms moving on sea bottom Infaunal = Benthic organisms moving through sediment beneath surface
Nekton = Pelagic organisms in water column that swim Plankton = Organism in water column that drift
Phytoplankton = Plankton that photosynthesis Zooplankton = Plankton the are heterotrophs
Only populations can evolve, not individuals
Populations are characterized by their reproductive potential, exceeded by pop. size needed and habitat capabilities
Eventually, growing populations out grow their habitat and competition between individuals becomes more intense
An organisms fitness is what helps achieve survival to reproductive age and the ability to pass on genes
Survival conditions continually change
At sea, salinity, temperature, oxygen availability, light and food availability and competition varies.
These mold community structure and ecosystems
Reproduction is the passing of genetic material to the next generation either sexually or asexually
3 types of asexual reproduction: Cellular fission, fission of multi-cellular and budding of multi-cellular
Sexual reproduction is the un-pairing of chromosomes in a process known as meiosis
- Halving of chromosomes = haploid 2. Haploid cells come together to form a diploid set of chromosomes in a zygote
Genetic diversity is stemmed from mutations and sexual reproduction
Most mutations are deleterious. Slow accumulation of non-fatal mutation in a population leads to diversity and even evolution.
Evolution due to natural selection, genetic drift and gene flow
Monera = unicellular prokaryotic bacteria (Cynobacteria, Bacteria and Archaea)
Protista = Unicellular eukaryotic organisms (Phytoplankton and Protozoa)
Plantae = multi-cellular photosynthetic organisms
Fungi = Heterotrophic organism with chitinous cell wall
Animalia = Multi-cellular heterotrophic organism lacking cell walls
Photosynthesis is a biochemical process that uses chlorophyll to absorb light.
Photosynthetic pigments and enzymes are contained in chloroblasts
Carbon dioxide + water + light = sugar + water + oxygen
Anaerobic respiration provides a mechanism to obtain energy in anoxic conditions
3 major categories of marine organisms: autotrophic primary producers (phytoplankton, plant), heterotrophic consumers (Zooplankton & nekton) and decomposers (Bacteria and fungi)
Producers = 1st level, herbivores = 2nd level, carnivores = 3rd & 4th levels
Biogeochemical cycles = Movement of nutrient compounds and dissolved gasses in cyclical nature from one ecosystem to another
Low efficiency of energy transfer between levels
Food chains complex and web like
Primary producers are often microscopic so size of organisms in upper levels is restricted
One species can occupy more then one level at different stages of its life
Some organisms form symbiosis relationships -
Parasitism = one benefits one has negative effects
Commensal = one benefits one (possibly) not affected
Mutualism = beneficial for all
Phytoplankton establish much of the structural characters of marine life
Density of marine organisms decreases at depth due to diminishing food supply, less light, and pressure
at depth, marine organisms depend on rain of detritus from photic level
Substances produced by primary producers usually absorbed by suspended bacteria which become food for specialized consumers (suspension feeders)
2 layers = Most organisms and all photosynthetic ones are in the photic zone. Fungi, microbes and some animals dependent on detritus rain live below