Biodiversity-and-Evolution

BIODIVERSITY AND EVOLUTION

Causes of Species Extinction

  • Species extinction can be linked to the failure of populations to adapt to abrupt environmental changes.

Biodiversity

Types of Biodiversity

  • Diversity of Species: Variety of species present in an ecosystem.

  • Diversity of Ecosystems: Range of different ecosystems available in a given area.

  • Diversity of Genes: Genetic variety within a species.

  • Biodiversity: The sum of all different species, including plants, animals, fungi, and microorganisms, and the habitats they occupy.

Impacts of Environmental Change

Consequences of Non-adaptation

  • If one component of biodiversity changes and does not adapt, it can lead to the decline or extinction of species.

Population and Community Dynamics

Population Definition

  • A population is the number of organisms of the same species in a specific region.

Community Definition

  • Communities are made up of different species living together in a shared environment.

Effects of Population Increase

  • An increase in one population can impact distribution of space and food resources.

Biodiversity Index

Understanding the Index

  • Biodiversity Index: A measure of the diversity of plant and animal species in an area, used to gauge ecosystem health.

  • Calculation:[ \text{Biodiversity Index} = \frac{\text{Total # of different Species}}{\text{Total # of Living Items}} ]

Limiting Factors

Definition

  • Factors that restrict the size of a population, helping maintain balance in ecosystems.

Examples of Limiting Factors

  1. Availability of food

  2. Water

  3. Living conditions

  4. Light

  5. Soil Nutrients

Carrying Capacity

Concept

  • Carrying Capacity: The maximum population size an environment can sustain.

  • Populations exceeding this limit will face resource shortages and decline.

Endangered and Threatened Species

Endangered Species

  • Species become endangered when populations are critically low; possible extinction is a risk.

  • Examples in the Philippines:

    1. Tamaraw

    2. Mouse Deer

    3. Philippine Deer

    4. Monkey-eating Eagle

Threatened Species

  • As populations decline rapidly, species are considered threatened before they become endangered.

  • As of 1991, several Philippine species including 89 birds, 44 mammals, and 8 reptiles are threatened.

Extinction

Definition

  • Extinction: The complete disappearance of a species upon the death of its last member.

Causes of Extinction

  • Changes to habitats, human activity, and natural disasters.

Natural Causes of Species Extinction

  1. Climate change

  2. Land development

  3. Acid precipitation

  4. Diseases/Epidemics

  5. Meteoric impact/Cosmic radiation

  6. Invasive species

  • Effect of invasive species: Alters food webs and ecosystem dynamics.

Man-Made Causes of Species Extinction

  1. Deforestation

  2. Pollution (air and water)

  3. Destruction of coastal resources

Evolution

Definition

  • Evolution: The gradual change of organisms over time, focusing on survival and adaptation.

Charles Darwin's Contribution

  • "Organisms best adjusted to their environment are the most successful in surviving and reproducing."

  • Emphasizes adaptability over strength or intelligence for survival.

Geologic Timescale

Overview

  • Divides the Earth's history into major eras:

    • Paleozoic Era: Prehistoric life and marine biodiversity development.

    • Mesozoic Era: Dominance of large creatures (dinosaurs).

    • Cenozoic Era: Emergence of warm-blooded animals including humans.