Chapter 2 Flashcards
Levels of biodiversity
- Species diversity: all species on earth
- Genetic diversity: genetic variation within species among both geographically separate populations and among individuals within single populations
- Ecosystem diversity:different biological communities and their associations with the chemial and physical environment
Definitions of a species
morphological, biological, evolutionary
Pros and cons of Morphological species definition
Pro: easy, visual, quick
Con: different morphs of same specie
Pros and cons of biological species definition
Pro: reproductive behavior is more unique from species to species so it is more accurate than morphological
Cons: interbreed/hybridize
pros and cons of evolutionary species definition
Pro: You can definitely tell if they are different species
Con: Requires access to expensive lab equipment, time consuming, can’t do it in the field
3 diversity measurements
alpha, gamma, beta
Alpha diversity
of species in a given community
Gamma diversity
species at larger geographic scale that include a number of ecosystems
- mountains, continent
Beta diversity
rate of change of species composition as one moves across a large region
- Calculation: gamma/alpha
Why is genetic diversity important?
- Necessary for any species to maintain reproductive viability, resist disease, and ability to adapt in changing environment
- genetically diverse species is more likely to adapt and survive
Gene pool
total array of genes and alleles in a population
What is the main way to distinguish species?
genetic code
how many species exist? what species dominate this number?
~2 million species described (most are insects)
How does species richness differ from species diversity? What are the methods for quantifying each?
Diversity: evenness in number of individuals per species
- Shannon Diversity Index
Richness: number of species in an area
- Count species
What is the difference between an ecosystem and the biological community?
Ecosystem: biota along with the physical and chemical elements
- Biotic and abiotic
Biological Community: just the living organisms within an ecosystem
What is an ecosystem engineer?
Species that extremely modify the physical environment through their activities
- Make completely different ecosystem
- Sometimes set back succession
What is succession?
Progression on evolution starting with pioneer species (the ones that are the first to arise and pave the way for the following species) and the small plants such as grasses and perennials (intermediate species) and then finally the climax community
