Evolution and Biodiversity APES Mr. Hudson

Biodiversity Includes several factors: Species diversity Ecosystem diversity Genetic diversity Functional diversity Processes of matter cycling, energy flow w/in food chains/webs

Importance? Vital to maintaining life on earth Supplies life with all form of natural capital Preserves water/air quality Keeps soils fertile

How so biodiverse? Evolution and natural selection Natural selection- individs. with certain traits enhance their ability to reproduce Increases likelihood of passing on these favorable traits *Natural selection drives evolution**

Fossils Most of our knowledge of evolution comes from fossils Only represent 1% of all species that ever lived

Populations can change over time Mutations—random DNA errors, favorable mutations passed down Adaptations—inheritable trait that allows organism to survive and reproduce more than others

Example Natural selection “fast” Bacteria exposed to an antibiotic Some will naturally be genetically resistant The resistant will pass on traits to offspring– resistant strain will replace non resistant strain

MRSA (Methicillin-Resistant Staphlyococcus aureus?

Geology affects nat. sel. Movement of earth’s continents have allowed animals to move from each other Speciation- form new species through natural selection from one species

Geographic isolation Groups of same species are isolated for long periods of time

Reproductive isolation Long term geographic isolation causes a shift in the gene pools through natural selection New species ultimately formed

Arctic fox Gray fox

Climate Sometimes climate changes too quickly, animals cannot adapt Go extinct

Extinction Eradication of entire species…………… forever

Species diversity Healthy, sustainable, productive ecosystems are diverse SPECIES DIVERSITY Species richness- # of diff. species Species evenness- # of individs. of a given species

Rainforest High species richness—many diff. species Low species evenness– only a few of each

Canada Canadian wilderness may have only a few types of trees (low richness), but thousands of them (high evenness) Fir, dogwood, cedar, pine, oak

Aspen Grove-- Canada

Species Richness is GOOODD!!! Think about it…..more species, for example—plants, will be more resilient as a community Less affected by drought More resistant to invasion by new insects Exploit resources differently Some plants short roots, others long Some bloom early, some bloom late

What roles do species play in an ecosys? Niche– species “role” or way of life Includes everything that affects survival/reproduction, resource needs, space it requires, temps it can tolerate. It is a pattern of living

Generalists vs. Specialists Generalists– LARGE NICHE cockroach Specialist– small i.e. pandas– only eat bamboo

Native/invasive (alien, exotic) Native—evolved with a specific ecosystem Invasive—introduced deliberately/accidentally

Invasives Purple loose strife

Indicator Species Provide early warning signs to damage i.e. dolphins– only clean in healthy clean water “canary in the cage”

Keystone species Have a large affect on abundance and types of other species in ecosystem Loss of a keystone can lead to population crashes/extinctions of other species

Example American alligator Large amount if habitat destroyed in 1950s Providing nesting mounds, feeding sites for other animals As numbers of alligators diminished, #’s of other species began diminishing

American Alligator Top predator– helps controls pop of all other species

Foundation species Shapes communities by creating/enhancing habitats for other species i.e. elephants knock over trees—creates openings for grasses/shrubs Gives smaller grazers food

Beavers Dam rivers—create ponds/wetlands for other species

Difference btw. Keystone/foundation species Foundation– help create species habitat Keystone—(can be foundational), but actively maintain ecosystem and help serve other species living there