Unit 2 - The Living World: Biodiversity

Env. Science!!

Types of Diversity

Ecosystem Diversity, Species diversity, Genetic Diversity

Ecosystem Diversity

the number of different habitats available in a given area

Species Diversity

the number of different species in an ecosystem and the balance or evenness of the population sizes of all species in the ecosystem

Genetic Diversity

how different the genes are of individuals within a population (group of the same species)

the more diversity in a population the better the population can respond to environment stressors like drought, disease, or famine.

Richness ( r )

the total number of different species found in an ecosystem

Evenness

a measure of how all of the individual organisms in an ecosystem are balanced between the different species.

indicates if there are one or two dominant species, or if population sizes are well balanced

High ( r )

generally a good sign of ecosystem health (more species means more quality resources like H₂O & Soil

Bottleneck Event

An environment disturbance (natural disaster/human habitat distruction) that drastically reduces population sizes & kills organisms regardless of their genome

- reduces genetic diversity

Inbreeding

Organisms mate with closely related “family” members

• most likey experienced in smaller populations

• leads to higher chance of offspring having harmful genetic mutations

Resilience

the ability of an ecosystem to return to its original conditions after a major disturbance

Ecosystem Services

Goods that come from natual resources or services/functions that ecosystems carry out that have measurable economic/financial value to humans.

Provisioning, Regulating, Supporting, Cultural

Provisioning Services

goods taken directly from ecosystems or made from natural resources (wood, paper, food)

disrupted by overharvesting, water pollution, clearing land for agriculture/urbanization)

Regulating Services

natural ecosystems do this to climate/air quality, reducing storm damage & healthcare costs (water purification, nutrient cycling)

disrupted by deforestation

Supporing Services

natural ecosystems do this to processes we do ourselves, making them cheaper & easier (bees pollinate crops)

disrupted by pollinator habitat loss & filling in wetlands for development

Cultural Services

Money generated by recreation (parks, camping, tours) or scientic knowledge

disrupted by deforestation, pollution, urbanization

Island Biogeography

study of ecological relations & community structure on islands

Two basic “rules” or observations of Island Biogeography

1. larger islands support more total species

   a. the larger the island, the greater the ecosystem diversity

2. Islands closer to the “mainland” support more species

   a. easier for colonizing organisms to get to island from mainland

Evolution on Islands

islands have limited space & resources, creating unique conditions for this; more pressure for species to adapt to narrower niches (roles)

Adaptive radiation

single species rapidly evolving into several new species to use different resources & reduce competition

Ecological Range of Tolerance

conditions such as temperature, salinity, pH, or sunlight that an organism can encdure before injury or death

Ecological Range of Tolerance - Zones

Optimal Range, Zone of psychological stress, Zone of intolerance

Optimal Range

where organisms survice, grow, & reproduce

Zone of psychological stress

organisms survive, but experience some stress such as infertility, lack of growth, decreased activity, etc.

Zone of intolerance

organism will die (thermal shock, suffocation, lack of food/water/oxygen)

Natural Disturbances

a natural event that disrupts the structure and or function of an ecosystem (tornados, hurricanes, asteroids, forest fires, droughts)

can be even greater than human disruptions

Periodic, Episodic, Random

Periodic (Natural Disrbances)

occurs with regular frequency (dry-wet seasons)

Episodic (Natural Disrbances)

occasional events with irregular frequency (hurricanes, droughts, fires)

Random (Natural Disrbances)

no regular frequency (volcanoes, earthquakes, & asteroids)

Migration

wildlife may migrate to a new habitat as the result of natural disruptions

Fitness & Adaptation

all populations have some genetic diversity, or variability in genomes of individuals; Genetic diversity exists

Adaptation

a new trait that increases an organism’s fitness

Fitness

ability to survive and reproduce

Natural Selection

organisms that are better adapted to their env. survive and reproduce more offspring

Selective pressure/force

the environmental condition that kills individuals without the adaptation

Environmental Change & evolution

the environment an organism lives in determines which traits are adaptations

- as environments change, different traits may become adaptations & old traits may become disadvantages

Pace of Evolution

-the more rapidly an environment changes, the less likely a species in the environment will be to adapt to those changes

-the more genetic diversity in a population, the better they’re able to adapt to env. change (higher chance that some individuals have good mutations)