General Characteristics Pteridophytes include horsetails & ferns 🌿. Used for medicinal purposes, soil-binding, and as ornamental plants. First terrestrial plants to develop vascular tissues (xylem & phloem) 🌱. Mostly found in cool, damp, shady places, though some grow in sandy soils. Life Cycle & Structure Main plant body is...
General Characteristics Gymnosperms (gymnos = naked, sperma = seed) have exposed ovules and seeds (not enclosed by fruit). Include medium to tall trees & shrubs. The giant redwood tree (Sequoia) is one of the tallest tree species. Root System Generally tap roots. Some have fungal mycorrhizal associations (e.g., Pinus)....
General Characteristics Angiosperms (flowering plants) have ovules enclosed within fruits (unlike gymnosperms, where ovules are naked). Pollen grains & ovules develop inside specialized reproductive structures called flowers. Seeds are enclosed within fruits. Largest group of plants, adapted to a wide range of habitats. Diversity in Angiosperms Range in size...
Ernst Mayr: The Darwin of the 20th Century Early Life and Passion: Born in Germany in 1904. Early fascination with birds sparked his interest in biology. Defining a Species: Revolutionized the concept of a species. Defined a species as a group of interbreeding populations reproductively isolated from others. This...
Characteristics of Living Things: Exclusive Characteristic: The ability to perceive events in the environment and retain their memory is a unique characteristic of living things. Distinguishing Feature: The ability to interact with the environment and undergo progressive evolution is a key feature that separates living organisms from non-living things. Biological Organization: The...
1. Introduction to Diversity The world is home to a large variety of living organisms, visible (e.g., plants, animals, birds) and microscopic. Biodiversity: Refers to the number and variety of organisms on Earth. Known and described species: 1.7–1.8 million. New species continue to be discovered with exploration. 2. Need...
1. Introduction to Taxonomic Categories Classification Process: Involves multiple hierarchical steps. Each step represents a rank or category. Taxonomic Hierarchy: Combination of all taxonomic categories. Categories are units of classification (referred to as taxa). Example: Insects: Share common features like three pairs of jointed legs. Classified into a rank/category...
Rich Variety of Life: Millions of plants and animals have been identified and described. A large number of organisms remain unknown. Organisms vary in size, color, habitat, physiology, and morphology. Need for Classification: The diversity of organisms necessitates defining characteristics for study. Biologists have established rules and principles for:...
Historical Perspective on Classification Primitive Classification: Early classification was instinctive and based on utility (food, shelter, clothing). Lacked scientific criteria. Aristotle’s Contribution: Used morphological characters for classification: Plants: Trees, shrubs, and herbs. Animals: Those with red blood and those without. Two-Kingdom System: Introduced by Linnaeus. Divided organisms into: Plantae:...
Kingdom Monera Bacteria: Sole members of Kingdom Monera. Most abundant microorganisms on Earth. Ubiquitous (found almost everywhere): Soil Extreme habitats (hot springs, deserts, snow, deep oceans) On/in other organisms as parasites Bacterial Shapes: Coccus (cocci): Spherical Bacillus (bacilli): Rod-shaped Vibrium (vibrio): Comma-shaped Spirillum (spirilla): Spiral Characteristics: Simple structure, but...