The Living World: Ecosystem Diversity
Species - A group of more or less distinct organisms that are capable of interbreeding with one another in nature to produce fertile offspring but do not interbreed with other organisms.
Biological diversity - The number, variety, and variability of Earth's organisms; consists of three components: genetic diversity, species richness, and ecosystem diversity.
Species richness - The number of species.
Genetic diversity - The genetic variety within all populations of that species.
Ecosystem diversity - The variety of ecosystems found on Earth.
Biological diversity - The number, variety, and variability of Earth's organisms; consists of three components: genetic diversity, species richness, and ecosystem diversity.
Species richness - The number of species.
Genetic diversity - The genetic variety within all populations of that species.
Ecosystem diversity - The variety of ecosystems found on Earth.
Humans depends on species to survive. Plants, animals, and other organisms are sources of food, clothing, and shelter.
Natural selection - The process in which better-adapted individuals - those with a combination of genetic traits better suited to environmental conditions - are more likely to survive and reproduce, increasing their proportion in the population.
As a result: population changes over time.
Evolution by natural selection consists of four observations :
- High reproductive capacity
- Heritable variation
- Limits on population, growth, or struggle for existence
- Differential reproductive success
Evolution - Cumulative genetic changes that occur over time in a population of organisms; evolution explains many patterns of distribution and abundance displayed in the natural world.
- Adaptation occurs when, over time, inherited traits that contribute to sustaining life are preserved while others that are unfavorable are eliminated.
The Peppered Moth
The light moths lost their advantage of camouflage as light surfaces were darkened by pollution, and so light moths were eaten more frequently by birds.
The light moths lost their advantage of camouflage as light surfaces were darkened by pollution, and so light moths were eaten more frequently by birds.