Unit 2: Biodiversity 🍃♻️🏞️💚🌱 Flashcards
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)
Higher biodiversity=
higher ecosystem/population health/ resilience
Richness
total number of different species found in an ecosystem
- high (r) is generally a good sign of ecosystem health (more species means more quality resources like H2O & soil)
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
Genetic diversity
the measure of how different the genomes (set of genes) are of the individuals within a population of a given species
caused by random mutations in copying of DNA & recombination of chromosomes in sex cells of parents lead to new gene combinations & new traits in offspring
more genetic diversity =
the better the population can respond to envirnomental stressors like drought, disease, or famine
a higher chance that some of the individuals in a population have traits that allow them to survive the environmental stressor
bottleneck effect
An environmental disturbance that drastically reduces population size & kills organisms regardless of their genome
Surviving population is smaller and because individuals died randomly, it doesn’t represent the genetic diversity (reduces genetic diversity) of the original population
new, smaller population is more vulnerable
inbreeding depression
when organisms mate with closely related “family” members
leads to a higher chance of offspring with harmful genetic mutations because of the similar genotypes of the parents
smaller populations are affected by this more
Resilience
the ability of an ecosystem to return to its original conditions after a major disturbance (wind storm, fire, flood, clear-cutting, etc.)
higher species diversity
more resilience
more plant species to repopulate disturbed ground, anchor soil, and provide food & habitat for animal species
ecosystem services
Goods and services provided by natural ecosystems that are beneficial to humans (often monetarily or life-sustaining)
provisioning services
Goods/products taken directly from ecosystems or made from natural resources (wood, paper, food, hunting, fruits, and veggies)
disrupted by overharvesting, water pollution, clearing land
Regulating services
natural ecosystems regulate climate/air quality, reducing storm damage and healthcare costs
Benefits provided by ecosystem processes that moderate natural conditions like climate and air quality
disrupted by deforestatton
supporting services
Natural ecosystems support processes we do ourselves, making them less costly and easier for us
services that enable the other types of ecosystem services to function
they generally affect humans indirectly and act over long periods of time
ex) providing habitat, cycling nutrients, creating soil, primary productivity
disrupted by pollinator habitat loss and filling in wetlands for development
Cultural Services
revenue from recreational activities (hunting/fishing licenses, park fees, tourism-related spending) & profits from scientific discoveries made in ecosystems (health/ag./educational knowledge)
Disrupted by deforestation, pollution, urbanization
humans disrupt ecosystem services
Human activities disrupt the ability of ecosystems to function, which decreases the value of ecosystem services they provide
This has ecological (natural) and economic (money-based) consequences
Island Biogeography
study of ecological relationships & community structure on islands
(can be actual islands in a body of water or figurative habitat islands)
Larger Islands
support more species
higher ecosystem diversity
larger pop size- more resistant to environmental disturbances
lower extinction rate (species less likely to die off)
positive correlation between island size and species richness
closer to mainland
higher species richness
easier for more species to migrate to island from mainland (swim/fly)
More continual migration of individuals to the island habitat
Frequent migration brings more genetic diversity & larger population size
further from mainland
fewer species
evolution on islands
different beaks quickly evolve to fit variety of different food sources on island
single colonizing species from mainland quickly evolves to many slightly different species to adapt to new island cond
ecological range of tolerance
range of conditions such as temperature, salinity, pH, or sunlight that an organism can endure before injury or death results
Species and individual organisms both have a range of tolerance for all the different environmental conditions
of their habitat
range of tolerance zones optimal range
range where organisms survive, grow, and reproduce
zone of physiological stress
range where organisms survive, but experience some stress such as infertility, lack of growth, decreased activity, etc.
zone of intolerance
range where the organism will die
Ex: thermal shock, suffocation, lack of food/water/oxygen
natural disturbance
A natural event that disrupts the structure and or function of an ecosystem
ex) Tornados, hurricanes, asteroids, forest fires, drought
periodic disturbance
occurs with regular frequency (ex: dry-wet seasons)
episodic disturbance
occasional events with irregular frequency (ex: hurricanes, droughts, fires)
random disturbance
no regular frequency (volcanoes, earthquakes, and asteroids)
natural climate change
Earth’s climate has varied over geologic time for numerous reasons
Sea level has varied over geological time as glacial ice on earth melts & forms
Environmental change=habitat disruption
Major environmental disturbances result in widespread habitat changes and or loss
Migration
Wildlife may migrate to a new habitat as the result of natural disruptions
adaptation
a new trait that increases an organism’s fitness (ability to survive and reproduce)
genetic diversity exists because:
Random mutations while DNA is being copied create new traits
Crossing over in parent chromosomes creates new combinations of genes (and therefore traits)
natural selection
organisms that are better adapted to their environment survive and reproduce more offspring
Individuals with adaptations pass them on to offspring & individuals without adaptations die off, which leads to the entire population having the adaptation over time (evolution)
selective pressure/force
the environmental condition that kills individuals without the adaptation
