Abiotic and Biotic Components in Ecosystems Source: Jones, M and G. Jones 1995 Biology. Cambridge...
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Transcript of Abiotic and Biotic Components in Ecosystems Source: Jones, M and G. Jones 1995 Biology. Cambridge...
Abiotic and Biotic Components in Ecosystems
Source: Jones, M and G. Jones 1995 Biology. Cambridge University Press.
United Kingdom
Abiotic and Biotic FactorsAbiotic: Non-living components of the
ecosystemPhysicalChemical
Biotic: Living componentsBiotic interactionsBiotic indexes
Studying Abiotic Factors
Abiotic Physical FactorspH (of soil and water): important factor in
the process of absorption of nutrients from the soil. Acidic soils inhibit absorption and decreases biological diversity.
Salinity: amount of dissolved salts. This factor has an effect on the absorption of H2O by osmosis. Some plants are adapted to soil with high salinity
Climate: influences natural populations The two most important factors are temperature
and precipitation
Temperature: temperatures higher than optimum denature enzymes; low temperatures inactivate enzymes. Has negative effects on growth, productivity and reproduction
Water (precipitation): Needed for vital activities (enzyme activity, transport, photosynthesis, support)
Light (intensity and duration): Important for photosynthesis, flowering, reproduction, phototropism. In dark areas of the world where there is low light intensity and duration
Abiotic Chemical Factors Soil: affects plants and therefore animals.
Plants rely on it for many of their requirements Provides: anchorage, nutrient minerals, water, air;
habitat
Oxygen: needed by most living organisms. Can quite often be in short supply in water (in
riffles there is large supply; in pools is sometimes depleted due to decomposition
BOD (biochemical oxygen demand) DO (dissolved oxygen)
Nutrients Phosphorus
Mineral Nutrients: Plants need a continuous supply of nutrients from the soil for manufacturing enzymes, proteins, vitamins, nucleotides and other compounds Phosphorus Mg Fe
Studying Biotic Factors
Biotic FactorsInclude descriptions of the following factors:
Availability of foodPredatorsParasitesCompetitionBiotic Indexes
Abundance or Pop. Size (random sampling)Density (# of organisms per area or volume)Biological diversity (biodiversity index)
Distribution (type):RandomClumpedUniform
Studying biotic components of ecosystemsRandom sampling: Using randomly selected representative samples. Including a large portion (sample) of the populationRandom Sampling using Quadrats: It can be any size, but one with sides of about 0.5 m is convenient in the fieldTransects: Allows us to see distribution of organisms in the field. A line crossing the field. A long calibrated line or tape could be used to record all plants/organisms touching the field or at certain intervalsMark-release-recapture: Use with animals that move around a lot.
Classification and Identification of Organisms
Why do we classify?To identify organismsTo make inferences about characteristicsTo establish evolutionary links
How do we name organisms?Binomial System
Five KingdomsProkaryota
Protoctista
Fungi
Plantae
Animalia
Classification from species to Kingdom HUMAN BLUE
WHALE
Kingdom Animalia Animalia
Phylum Chordata Chordata
Class Mammalia Mammalia
Order Vertebrata Cetacea
Family Hominidae Balaenopteridae
Genus Homo Balaenoptera
species sapiens musculus
Evidence used in classificationFossil record
Biochemical evidence
Anatomical Structures
Geographical Distribution
Identifying OrganismsDichotomous or Taxonomic Key
Practice: Taxonomic Key for snakes and for
salamanders