AICE Marine TOPIC 4

AICE Marine Science: Topic 4 Study Guide

4.1 The Classification of Marine Organisms

• Taxonomic Hierarchy: Species are classified into the following levels:

  1. Kingdom

  2. Phylum

  3. Class

  4. Order

  5. Family

  6. Genus

  7. Species

• Dichotomous Keys:

  • Used to identify organisms based on physical characteristics.

  • Consists of paired statements that lead to the correct classification.

4.2 Key Groups of Marine Organisms

• Bony Fish vs. Cartilaginous Fish

  • Both belong to the phylum Chordata.

  • Bony Fish (Osteichthyes): Have a skeleton made of bone, operculum covering gills, and a swim bladder.

  • Cartilaginous Fish (Chondrichthyes): Have a skeleton made of cartilage, gill slits, and no swim bladder.

  • Be able to label the external anatomy of both fish types.

• Binomial Nomenclature:

  • Uses two names: Genus species (e.g., Homo sapiens).

• Drawing and Observations:

  • Be prepared to observe and sketch unfamiliar marine specimens.

• Echinoderms:

  • Key features: Pentaradial symmetry and tube feet (e.g., starfish, sea urchins).

• Crustaceans:

  • Key features: Exoskeleton, jointed appendages, and segmented bodies (e.g., crabs, lobsters, shrimp).

4.3 Biodiversity

• Three Types of Biodiversity:

  1. Genetic Diversity: Variation in genes within a species.

  2. Species Diversity: Variety of species in an ecosystem.

  3. Ecological Diversity: Variety of ecosystems in a region.

• Importance of Marine Biodiversity:

  • Provides ecosystem services like oxygen production, coastal protection, and food sources.

4.4 Populations and Sampling Techniques

• Key Ecological Terms:

  • Ecosystem: Community of organisms interacting with abiotic and biotic factors.

  • Niche: Role of an organism in its environment.

  • Species: Group of organisms that can interbreed.

  • Population: Group of the same species in an area.

  • Community: All populations living together in an ecosystem.

• Abiotic vs. Biotic Factors:

  • Abiotic (Non-living): Temperature, salinity, pH, light.

  • Biotic (Living): Predation, competition, symbiosis.

• Mark-Release-Recapture Method:

  • Used to estimate population size.

  • Steps:

    1. Capture and mark a sample of individuals.

    2. Release them back into the habitat.

    3. Recapture another sample and count how many are marked.

  • Lincoln Index Formula: where:

    • = number of individuals marked initially

    • = number of individuals in second sample

    • = number of marked individuals in second sample

  • Limitations: Assumes no immigration/emigration, no births/deaths, and even mixing of individuals.

• Sampling Methods:

  • Random Sampling: Avoids bias, ensures representative data.

  • Systematic Sampling: Samples taken at regular intervals (e.g., along a transect).