3rd Form Biology: Classification and Taxonomy

Study Notes

Taxonomic Ranking

Classification is the process of grouping organisms based on their similarities and differences
The taxonomic ranking is as follows:
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species

Kingdom Plantae

Has four phyla:
- Bryophyta
  - Simple stems and leaves
  - Single rootlet called rhizoids
  - Reproduce by spores
- Pteridophyte
  - Simple roots, stems, and leaves
  - Vascular tissue
  - Reproduce by spores under the leaf
- Coniferophyte
  - Seeds grow inside cones
  - Roots, stems, and leaves
  - Vascular tissue
- Angio Spermatophyta
  - Vascular tissue
  - Reproduce by seeds in fruits
  - Proper roots, stems, and leaves
  - Divided into two groups: Monocotyledons and Dicotyledons

Monocotyledons and Dicotyledons

Monocotyledons:
- One cotyledon
- Fibrous roots
- Leaves attached by a sheath
- Leaf veins are parallel
Dicotyledons:
- Two cotyledons
- Tap root
- Leaves attached by a petiole
- Leaves have a network of veins

Kingdom Animalia

Has eight phyla:
- Porifera
  - Stationary organisms
  - Lack tissues and organs
  - Body contains a single cavity with many pores
- Cnidaria
  - Bag or umbrella-shaped body
  - Simple opening which is the mouth
  - Ring of tentacles around the mouth
- Platyhelmithes
  - Long, flat, unsegmented body
  - Some are parasites
- Annelida
  - Elongated body divided into segments
  - Body has bristles called setae
- Echinodermata
  - Body based on a radial pattern of 5 parts
  - Segmented body
  - Several pairs of jointed legs
- Mollusca
  - Soft, moist, unsegmented body
  - Muscular foot
  - Many have shells
- Arthropoda
  - Class Crustacea
    - 2 pairs of antennae
    - Usually have more than four pairs of legs
    - 3 body segments
  - Class Arachnida
    - No antennae
    - Four pairs of legs
    - 2 body segments
  - Class Insecta
    - One pair of antennae
    - 3 pairs of legs
    - 3 body segments
    - Pair of compound eyes
  - Class Chilopoda
    - Long body with many segments
    - Each body segment has one pair of legs
    - One pair of antennae
  - Class Diplopoda
    - Long body with many segments
    - Each body segment has 2 pairs of legs
    - One pair of antennae
- Chordata
  - Class Pices
    - Scales
    - Gills for breathing
    - Fins for swimming
    - Cold-blooded
  - Class Amphibia
    - Soft, moist skin without scales
    - Eggs laid in water, adults live on land
    - Larvae have gills, adults have lungs
  - Class Reptilia
    - Dry, waterproof skin with scales
    - Lay eggs with a rubbery shell on land
    - Cold-blooded
  - Class Aves
    - Feathers, beaks, and wings
    - Lay eggs with a hard shell
    - Warm-blooded
  - Class Mamalia
    - Hair (or fur)
    - Feed their young on milk
    - Developed brain
    - Warm-blooded

Ecology

Study of the interrelationships of living organisms with each other and their environment
Key definitions:
- Environment: combination of factors that surround and act on an organism
- Abiotic: non-living chemical and physical factors
- Biotic: living organisms
- Species: group of organisms of common ancestry that closely resemble each other
- Ecosystem: community of living organisms interacting with each other and with their abiotic environment
Methods for carrying out an ecological study:
- Quadrat: used to count stationary or slow-moving organisms
- Pitfall trap: used to sample crawling or walking organisms on the ground
- Sweep net: used to sample flying insects
- Line transect: a measuring tape/string with marks at regular intervals
- Belt transect: a strip of fixed width
Abiotic factors:
- Aquatic factors: affect organisms living in aquatic habitats
  - Salinity
  - Dissolved oxygen
- Climatic factors:
  - Light
  - Temperature
  - Humidity
  - Water availability
- Edaphic factors: connected with the soil
  - Water
  - Air
  - Mineral nutrients
  - pH
  - Humus
Types of soil:
- Sand: large and loosely packed particles
- Clay: very small particles
- Loam: moderate water and a fertile mixture of sand, clay, and...
Food chain:
- A chart showing the flow of energy from one organism to another
- Arrows signal the direction of the energy flow
- Consumers may be classified into:
  - Herbivores
  - Carnivores
  - Omnivores