Environmental Science: Biodiversity Overview

Biodiversity Overview

• Term "biodiversity" was first coined by Walter G. Rosen in 1986.
• Biodiversity encompasses various life forms, including unicellular organisms like bacteria and multicellular organisms such as plants, fish, and mammals.
• It represents the total of genetic, species, and ecosystem diversity which constitute essential life support for humans.

Types of Biodiversity

• Genetic Diversity: Variation of genetic characteristics within a species, influencing long-term survival. An example includes different dog breeds resulting from selective breeding.
• Species Diversity: Refers to the number and abundance of species in a particular habitat or ecosystem. Species serve as the basic units of biological classification.
• Ecosystem Diversity: Involves variety among ecosystems, including different habitats and community types, crucial for the biosphere's structure and function.

Distribution of Biodiversity

• Biodiversity distribution is uneven globally, with terrestrial biodiversity significantly greater than marine biodiversity, at a ratio of 25:1.
• Biogeography studies the spatial distribution of organisms, species, and ecosystems.

Threats to Biodiversity (HHPAGOD)

• Habitat Destruction: This is the primary cause of species extinction worldwide, driven by human population pressure.
• Habitat Fragmentation: Occurs due to human activities, reducing species' ability to thrive.
• Pollution: Introduction of harmful substances like nutrients and chemicals disrupting ecosystems.
• Alien Species: Non-native species introduced into new regions without natural predators, threatening local biodiversity.
• Global Climate Change: Alters biotic and abiotic elements of ecosystems, leading to species endangerment.
• Over-Exploitation: Illegal wildlife trade and overfishing threaten numerous species.
• Disease: Increased population density due to habitat loss often leads to disease outbreaks.

Reasons for Habitat Loss

• Human activities causing habitat loss include agriculture, resource harvesting, industrial development, and urbanization.

Solutions for Biodiversity Conservation

• Protect remaining natural habitats and educate the public about biodiversity's importance.
• Encourage habitat restoration through tree planting and home gardening.
• Control human population growth and reduce urbanization's impact.

Poaching and Its Implications

• Poaching involves the illegal hunting and harvesting of wild plants and animals.
• Driven by demand for animal parts and traditional medicinal beliefs, leading to significant biodiversity loss.

Recent Issues on Biodiversity

• Approximately 75% of genetic diversity in crop plants lost over the past century; three species extinctions occur every hour.
• One-third of coral reefs are destroyed, with 24% of mammals and 12% of birds globally threatened.
• Over 50% of wetlands drained since 1970, leading to severe declines in wetland species populations.

Conservation Techniques (CCRRIPE)

• Control urbanization and strengthen environmental legislation.
• Utilize biotechnology for conservation efforts.
• Restore habitats and revise agricultural practices focused on sustainability.
• Provide environmental education to raise awareness.

Evolutionary Concepts

• Evolution denotes the development and diversification of living organisms from earlier forms over time.

Fossil Types

• Imprint Fossils: Created by organisms leaving tracks in sediment, later preserved by covering layers.
• Compression Fossils: Formed when organisms are preserved in sedimentary rock under physical pressures.
• Trilobites: Extinct arthropods known for their segmented bodies and fossilized exoskeletons.
• Crinoids: Marine animals resembling plants, part of the Echinodermata phylum.
• Dinosaur Bone Fossils: Include body fossils (bones) and trace fossils (tracks).
• Vascular Plant Fossils: Represent early vascular plants appearing in the fossil record around 410 million years ago.

Comparative Anatomy and Evolution

• Homologous Structures: Similar physical features shared by organisms with a common ancestor serving different functions.
• Embryonic Development: Early-stage embryos of various species display similarities, indicating common ancestry.
• Jean Baptiste de Lamarck: Introduced theories of use and disuse, and inheritance of acquired traits.
• Charles Darwin: Proposed natural selection, stating species undergo evolution through adaptation and survival of the fittest, leading to the concept of "Darwinism".

Fossil Dating Techniques

• Relative Dating: Organizes fossils and rock layers by age.
• Radiometric Dating: Calculates the actual ages of rocks using radioactive decay.

Geologic Time Scale

• A chronological system relating geological strata to time, aiding in understanding the Earth's history and the evolutionary timeline.