Body Cavity: The presence or absence of a cavity between the body wall and the gut wall is a key factor in animal classification. COELOM: A body cavity that is fully lined by mesoderm. Coelomates: Animals that possess a true coelom. Examples include: Annelids Molluscs Arthropods Echinoderms Hemichordates Chordates...
Animal Symmetry: Animals can be categorized based on their body symmetry. ASYMMETRY: Sponges are mostly asymmetrical.No plane passing through the center can divide them into equal halves. RADIAL SYMMETRY: Coelenterates, ctenophores, and echinoderms exhibit radial symmetry.Any plane passing through the central axis of the body divides the organism into...
DIGESTIVE SYSTEMS: Incomplete Digestive System: Single opening to the outside.This opening serves as both mouth and anus. Example: Platyhelminthes (flatworms). COMPLETE DIGESTIVE SYSTEM: Two openings: mouth and anus.Food enters through the mouth and waste exits through the anus. CIRCULATORY SYSTEMS: OPEN CIRCULATORY SYSTEM: Blood is pumped out of the...
Levels of Organization in Animalia MULTICELLULARITY: All members of Animalia are multicellular. However, the organization of these cells varies significantly. CELLULAR LEVEL OF ORGANIZATION: Example: Sponges Description: Cells are arranged as loose aggregates. There is some division of labor among cells, but no true tissues are formed. TISSUE LEVEL...
Need for Classification: There are over a million species of animals described, making classification crucial. Classification helps in organizing animals based on their similarities and differences. It also helps in assigning a systematic position to newly discovered species. Common Features Across Animal Species: Despite differences in structure and form,...
How Do We Conserve Biodiversity? 1. Approaches to Biodiversity Conservation Biodiversity conservation can be broadly categorized into two approaches: In Situ Conservation (On-site conservation) Ex Situ Conservation (Off-site conservation) 2. In Situ Conservation This approach involves protecting entire ecosystems to conserve the biodiversity within them. Definition: Conserving species in...
sources. 2. Broadly Utilitarian Arguments Ecosystem Services Provided by Biodiversity: Biodiversity underpins essential natural services that maintain ecological balance: Oxygen Production: The Amazon rainforest contributes 20% of Earth’s oxygen through photosynthesis. Economic value of oxygen production can be understood by considering the cost of medical oxygen cylinders. Pollination Services:...
The accelerated rates of species extinction today are primarily due to human activities. These causes are often referred to as ‘The Evil Quartet.’ 1. Habitat Loss and Fragmentation Primary Cause: The most significant driver of species extinction. Tropical Rainforests: Once covered 14% of Earth’s land surface, now reduced to...
1. Decline in Biodiversity Ongoing Losses: Although speciation (formation of new species) seems rare, species loss is an undeniable reality. Human Activities as a Major Cause: Example: Colonization of tropical Pacific Islands led to the extinction of 2,000+ native bird species. IUCN Red List (2004): 784 species have gone...
Key Question Does the number of species in a community matter to ecosystem functioning? Ecologists have debated this for years, but no definitive answer exists. Stability in a Biological Community A stable community is characterized by: Consistent Productivity: Minimal variation in productivity from year to year. Resistance/Resilience: Ability to...