Biodiversity BIO 350

Biodiversity BIO 350 - Biodiversity I Species A A...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Biodiversity I Species A A population of morphologically (structurally) similar organisms that can sexually reproduce among themselves but cannot produce fertile offspring when mated with other organisms. 1. Reproductive isolation is the key feature. B So, how many species do we think are out there? 1. We have identified a bit fewer than 2 million species. 2. New species are constantly being found, especially in the tropics (rate is about 10,000 new species per year). 3. As many as 3 to 50 million species may be on our planet. 4. The vast majority of species are invertebrates (those animals without backbones) - maybe up to 95% of all species. a) Insects represent the largest group. i) Over 450,000 species of beetles alone have been described. ii) Compare this to the number of species of mammals: about 4,000. iii) There are only 270,000 species of plants. iv) Insect species equal in number all other organisms together! (a) For every human alive today, there are about 200-300 million individual insects. II Measuring biodiversity A Species richness 1. The number of different species in a community 2. The biggest factors affecting species richness are the complexity of the community and the number of potential niches 3. Also a factor is the relative isolation of the community from other communities a) near-shore islands have more species than distant islands 4. A third factor is the size of the community a) large areas have more species than small areas. B Genetic Diversity 1. The variety of genes within all populations of a species 2. Reflects the potential of a species to adapt to environmental changes a) Fewer genes in a population means less variation for natural selection to work with b) A population with little variation is more likely to go extinct. whereas a population with a lot of variation has the potential to evolve into a new species (adding to species richness) C Ecosystem Diversity 1. The variety of interactions (competition, predation, symbiosis) among organisms in a community 2. Essentially, a reflection of species richness (more species give the potential for more types of interactions) 3. The more diverse an ecosystem the more ecological services it can provide (see table 15.1 p. 364) 4. Diverse ecosystems are more resistant to environmental changes Biodiversity Page 1 III So, how do we benefit from this biological diversity? A Provide sources for agriculture, forestry, aquaculture, animal husbandry. 1. Genetics - genes obtained from wild relatives of agricultural crops and inserted into these crops convey resistance from diseases. Genetic improvements in crops in the U.S. accounts for an average increase in harvest value by $1 billion per year from 1930 to 1980....
View Full Document

This note was uploaded on 06/23/2008 for the course BIO 350 taught by Professor Gillespie during the Spring '08 term at Los Rios Colleges.

Page1 / 6

Biodiversity BIO 350 - Biodiversity I Species A A...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online