Evolution: Theories, Fossils, and Relationships

• Evolution involves change and is a continuous process.
• The idea that the world is stable and unchanging does not describe evolution.
• Mutation leads to evolution.
• The oldest fossils are found in the Pre-Cambrian Era.
• Similarity in genomic DNA is a more definitive characteristic to show the relatedness of two organisms.
• Extinction allows other organisms to develop, evolve and progress.

Theories

• The Theory of Use and Disuse states that organs not in use will disappear, while organs in use will develop.
• The Theory of Natural Selection says that only the fittest organisms will survive in a given environment.

Homologous Structures and Evolutionary Relationships

• Flipper of whale and forelimb of cat are examples of homologous structures.
• Body structures develop because they are used extensively, according to Lamarck’s Theory of Use and Disuse.
• Organisms with close biochemical similarities show stronger evolutionary relationships as they share a common ancestor and have the same kind of proteins.

Threats to Wildlife and Biodiversity

• Loss of habitat is a major cause of decreasing wildlife populations.
• Direct economic value refers to the value of species as sources of food, medicine, clothing, shelter, and energy.
• Biodiversity describes how varied life forms are in different ecosystems.
• DENR (Department of Environment and Natural Resources) is the agency responsible for protecting natural and wildlife resources.
• A population is a group of organisms of the same species living in a certain area.
• Carrying capacity is the maximum number of a population an environment can support.
• Emigration occurs when a population approaches its carrying capacity, and organisms leave to find resources elsewhere.
• An ecosystem is a community of organisms that live, feed, and interact with the environment.
• Limiting factors control the growth of a population.
• Davao's wide variety of fruits demonstrates the direct economic and ethical/cultural value of biodiversity.

Environmental Issues and Population Dynamics

• Dumping garbage and toxic waste into a river ecosystem will cause it to become a wasteland.
• The population will decrease when guinea pigs are aggressive towards each other, the young are less healthy and more young guinea pigs die.

Explore evolution's continuous change, driven by mutation and natural selection. Discover the Theory of Use and Disuse and how the fittest organisms survive. Learn about homologous structures and genomic DNA in determining evolutionary relationships.