Chapter 5 Highlights Mrs. Thompson APES 2014

Key Ideas Describe biodiversity and how it is measured Relate biodiversity to resilience and survival Describe changes that lead to evolution or extinction Compare and contrast different types of niche’ and why they are important to resource partitioning

Biodiversity Applies to many different levels of organization – Genetic diversity leads to…. – Species diversity which leads to…. – Ecosystem diversity Biodiversity impacts a species/ecosystem’s resilience and survival during change (quick forest activity)

Biodiversity Can measure – Species richness (number of different species within a given area) OR – Species evenness (ratio of one species to another) – Shannon’s Index represents BOTH measurements

Sources of Diversity Genetic Diversity— – Mutation – Genetic recombination (crossing over, independent assortment, random segregation, sexual reproduction) – REVIEW VOCABULARY– genotype, phenotype, genes, chromosome etc.

Sources of Diversity Species Diversity Artificial selection – selective breeding – Genetic Engineering – Genetically Modified Foods (plants) REVIEW VOCABULARY– fitness, adaptation, geographic isolation, reproductive isolation Natural selection (5 steps) – Overproduction – Genetic Diversity – Struggle to Survive – Environmental Change (isolation or change in fitness) – Differential Reproduction

Species Diversity Natural Selection operates on LARGE DIVERSE populations only…NOT – Those with low diversity OR – Small populations

Species Diversity Small populations become LESS diverse over time – Genetic Drift – Bottleneck effect – Founder effect ALL OF THESE RESULT IN MORE HOMOGENOUS POPULATIONS And may result in “Extinction Vortex”

In General…. The faster the environmental change…. The less genetic diversity… The smaller the population… The longer it takes to mature… THE MORE LIKELY A SPECIES WILL GO EXTINCT

Niche Niches partition resources to allow competing species to survive

Types of Niche Fundamental Niche– ideal conditions, where it could live Realized Niche– available conditions, where it really lives Niche generalists– species who’s fundamental niche is broad Niche specialists– species who’s fundamental niche is narrow