Biodiversity and Evolution

• Biodiversity the variety of earth's species, the genes they contain, the ecosystem in which they live, and the ecosystem processes of energy flow and nutrient cycling that sustain all life
• Functional diversity, the biological and chemical processes such as energy flow and matter recycling needed for the survival of species, communities, and ecosystems
• Ecological diversity, the variety of terrestrial and aquatic ecosystems found in an area or on the earth
• Species diversity, the number and abundance of species present in different communities
• Genetic diversity, the variety of genetic material within a species or a population
• Biological evolution, the process whereby earth's life changes over time through changes in the genetic characteristics of populations
• Natural selection, individuals with certain traits are most likely to survive and reproduce under a particular set of environmental conditions than are those without the traits
• Other mechanisms of evolution

  • Mutation
  • Genetic drift
  • Nonrandom mating
  • Migration
• Mutation, random changes in the DNA molecules of any gene in a cell. Only mutations taking place in genes of reproductive cells are passed on the offspring
• Genetic drift, Allele frequencies change purely by chance events, especially in small populations
• Founder effect, occurs when a small group of individuals leaves its home population and establishes a new, isolated settlement
• Bottleneck effect, occurs when population's size drops rapidly over a short periodeffect occurs
• Migration, the movement of individuals into or out of a population. Departing members of a population take their alleles with them. Likewise, new members entering and interbreeding with an existing population may add new alleles
• Geological processes affect natural selection

  • The locations (latitudes) of continents and oceanic basins have greatly influenced the earth's climate and thus helped to determine where plants and animals can live
  • The movement of continents has allowed species to move, adapt to new environments, and form new species through natural selection
  • The shifting of tectonic plates, which results in earthquakes, can also affect biological evolution by causing fissures in the earth's crust that can separate and isolate of populations of species
• Speciation, one species splits into two or more different species. A new species is formed when one population of a species has evolved to the point where its members no longer can breed and produce fertile offspring with its members of another populations that did not change or that evolved in a different way
• Types of speciation

  • Geographic isolation (allotrophic)
  • Peripatric speciation
  • Parapatric isolation
  • Sympatric isolation
• Extinction a process in which an entire species ceases to exist (biological extinction) or a population of species becomes extinct over a large region, but not globally (local extinction)
• Five major mass extinctions

  • The Ordovician Mass Extinction
  • The Devonian Mass Extinction
  • The Permian Mass Extinction
  • The Triassic-Jurassic Mass Extinction
  • Cretaceous-Tertiary Mass Extinction
• Species diversity, the variety and abundance of species in a particular place
• Species richness, the number of different species contained in the community
• Species evenness, the relative abundance of individuals within each of the species in a community
• Species-rich ecosystems tend to be productive and sustainable
• Ecological niche, the role that a species plays in its ecosystem. It is a species' way of life in a community and includes everything that affects its survival and reproduction
• Types of species in an ecosystem

  • Native species
  • Nonnative species
  • Indicator species
• Geographic Isolation occurs when different groups of the same population of a species become physically isolated from one another for a long period of time.
• Reproduction Isolation is a long term geographic separation of members of a particular sexually reproducing species, enough for them to become so different in genetic makeup that they cannot produce live, fertile offspring if they are rejoined.
• Allopatric Speciation, speciation in a geographically separate population
• Peripatric Speciation happens when one of the isolated population has very few individuals
• Parapatric Isolation is where habitat zones of two diverging populations are not entirely separated, meaning there are no geographic obstacles between the parent species and diverging- there is a small, shared habitat area directly adjacent but usually environmentally different habitats
• Two Sympatric Isolation

  • Behavioral Isolation
  • Temporal Isolation
• Behavioral Isolation, species choose mates based on different behaviors
• Temporal Isolation, species mate at different times of year or times of day
• Background Extinction species have disappeared at a low rate (normal extinction of various species as a result of changes in local environmental conditions).
• Mass Extinction, is a catastrophic, widespread, often global event in which major groups of species are wiped out over a short time compare with normal (background) extinction.
• Generalist is a large and wide nice wide range of diet tolerates a wide range of environmental variations, tolerates environmental changes, commonly invasive species.
• Specialist is small and narrow niche, limited and unique diet requirements more likely to suffer from habitat loss and become endangered, does not tolerate environmental changes, commonly found in stable climax communities.
• Native Species are those species that normally live and thrive in a particular ecosystem
• Nonnative Species are species that migrate into, or are deliberately or accidentally introduced into, an ecosystem.
• Indicator Species are species that provide early warnings of damage to a community or an ecosystem.
• Keystone Species have a large effect on the types and abundance of other species