Unit 2 - The Living World: Biodiversity Flashcards
biodiversity
a measure of richness (# of different species) and evenness (# of individuals of each species) in a given area
species diversity
- the number of diff species in an ecosystem
- the balance/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)
ecosystem diversity
variations in species, communities, habitats, and processes in a given region
higher biodiversity
higher ecosystem or population health
richness (r)
is the total number of different species found in an ecosystem
evenness
is a measure of how all of the individuals organisms in an ecosystem are balanced between the different species
bottleneck event
- an environmental disturbance that drastically reduces population size and kills organisms regardless of their genome
- reduces genetic variation
inbreeding depression
- when organisms mate with closely related family members
- higher chance of offspring having harmful genetic mutations because they receive similar genotypes from parents
- smaller populations are more likely to experience inbreeding
ecosystem resilience
- the ability of an ecosystem to return to it’s original conditions after a major disturbance
- high species diversity = high ecosystem resilience
ecosystem services
goods that come from natural resources or services or functions that ecosystems carry out that have measurable economic/financial value to humans
provisioning
- goods produced directly from ecosystems or made from natural resources (wood, paper, food, fish, honey)
- ex: fish, hunting, lumber, paper
regulating
- natural ecosystems regulate climate/air quality, reducing storm damage and healthcare costs
- ex: trees in a forest store CO2 through photosynthesis which reduces rate of climate change and lessens damage caused by rising sea level and reduces crop failure from drought
supporting
- natural ecosystems support processes we do ourselves, making them cheaper and easier (bees pollinate crops)
- provide a service that would be costly to humans to generate
- ex: wetland plant roots filter pollutants, leading to cleaner groundwater; we don’t have to pay as much to purify water with expensive water treatment plants
cultural
- money generated by recreation (parks, camping) or scientific knowledge
- ex: national parks, fisherman pay for fishing licenses to catch fish in clean rivers
island biogeography: larger islands
- support more total species
- the larger the islands, the greater the ecosystem diversity
- greater ecosystem diversity = more food and habitat resources
- more niches, or “roles” organisms can play
- as size of island increases, biodiversity increases
island biogeography: islands closer to the mainland
- easier for colonizing organisms to get into island from mainland
- more colonizing organisms = more genetic diversity in new populations
- as distance from the mainland increases, biodiversity decreases
relative abundance
the number of individuals per species
describe 5 way that humans have disrupted ecosystem services on earth
a) Deforestation has led to cutting down and releasing excess amounts of carbon back into the atmosphere leading to climate change.
b) Pesticides have led to the reduction in the bee population which has decreased rates of pollination.
c) Clearing wetlands have led to less flood control and more damage from storm systems.
d) Bottom trawling has led to the destruction of coral reefs which provide habitats for fish and other species.
e) Overuse of water and draining aquifers, water can’t replenish quickly enough to keep up with demand
ecological range of tolerance
- The conditions in which an organism can survive.
- Many different physical, abiotic (non- living) factors influence where species live, including temperature, humidity, soil chemistry, pH, salinity and oxygen levels.
zone of optimum
the area where the population is in ideal conditions allowing organisms to thrive
zone of physiological stress
range where organisms survive but experience some stress, such as infertility, lack of growth, decreased activity
zone of intolerance
range where the organism will die
generalist species
survive in a wide range of conditions and has a varied diet. often omnivores
ex: racoon
specialist species
- survive in a narrow range of conditions and have a limited diet. susceptible to habitat disruptions
- ex: pandas
ecological resistance
ability of an ecosystem to maintain normal functions and processes during a disturbance
ecological resilience
ability of an ecosystem to recover after a disturbance
natural disturbance
- a natural event that disrupts the structure and or function of an ecosystem
- can be even greater than human disruptors
- ex: tornados, hurricanes, forest fires, disease, volcanic eruption
periodic
occurs with regular frequency
episodic
occasional events with irregular frequence
natural climate change
- earths climate has varied over geologic time for numerous reasons
- slight changes in earth’s orbit and tilt cause mini ice ages and warmer periods
- sea level has varied over geologic time as glacial ice on earth melts and forms
genetic diversity exists because
- random mutations while DNA is being copied create new traits
- crossing over in parent chromosomes creates new combinations of genes
adaptation
- a new trait that increases an organisms fitness (ability to survive and reproduce)
natural selection
organisms that are better adapted to their environment and reproduce more offspring
selective pressure/force
the environmental condition that kills individuals w/o the adaptation
ecological succession
a series of predictable stages of growth that a forest goes through
primary succession
- starts from bare rock in an area with no previous soil formation
- mass and lichen species carried by the wind grow directly on rocks, breaking them down to form soil
ex: newly formed islands, after volcanic eruption
secondary succession
- starts from already established soil in an area where a disturbance (fire/tornado/human land clearing) cleared out the majority of plant life
ex: after a fire or flood
benefits of fire
- Removes leaf litter and ground vegetation which can trigger forest regrowth.
- Maintains native species especially those adapted to withstand fire (or those whose seeds aren’t released except with fire).
- Thins the forest canopy so sunlight can reach the forest floor and saplings can grow.
- Prescribed fires are controlled and implemented at intervals.
What biomes need fire for plant germination?
prairie, savannas, and coniferous forests
pioneer species
- appear first, when the ground is simply bare rock or soil after a disturbance
- characteristics: seeds spread by wind or animals, fast growing, tolerant of shallow soil and full sunlight
ex: moss, lichen, wildflowers, raspberries, grasses, or sedges
stages of succession are characterized by
- which types of plant species dominate the ecosystem
- different species are adapted to the conditions of different stages
mid-successional species
- appear after pioneer species have helped develop deeper soil with more nutrients by their cycles of growth/death
- characteristics: relatively fast growing, larger plants that need deeper soils with more nutrients than pioneers, sun tolerant
late successional/climax community species
- appear last, after soil is deepened and enriched with nutrients by cycles of growth and death by early and mid successional species
- characteristics: large, slow growing trees that are tolerant of shade and require deep soils for large root networks
ex: maples, oaks, other large trees
keystone species
- this species is crucial to keep the ecosystem in balance
- often a dominant predator whose removal allows a prey population to explode and often decreases overall diversity
ex: otter, wolf
indicator species
species that can be used to infer the ecosystem health
ex: tiger salamander, golden toad
provisioning is disrupted by
overharvesting, water pollution, clearing land for agriculture/urbanization
regulating is disrupted by
deforestation
supporting is disrupted by
pollinator habitat loss and filling in wetlands for development
cultural services are disrupted by
deforestation, pollution, urbanization
