unit 2 Flashcards
Ecosystem diversity
the number of diff. habitats available in a given area
Species diversity
the number of diff. species in an ecosystem and the balance or evenness of the pop. sizes of all species in the ecosystem
Genetic diversity
how different the genes are of individuals within a population (group of the same species)
Evenness
measure of how all of the individual organisms in an ecosystem are balanced between the different species
Richness
total number of different species found in an ecosystem
Genetic diversity
measure of how different the genomes (set of genes) are of the individuals within a population of a given species
Bottleneck events
natural disaster/human hab. destruction) that drastically reduces pop. size & kills organisms regardless of their genome
Inbreeding
when organisms mate with closely related “family” members, Leads to higher chance of offspring having harmful genetic mutations because they’re getting similar genotypes from both parents
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 =
higher ecosystem resilience
Provisioning
Goods taken directly from ecosystems or made from nat. resources (wood, paper, food)
Regulating
Nat. ecosystems regulate climate/air quality, reducing storm damage & healthcare costs
Supporting
Nat. ecosystems support processes we do ourselves, making them cheaper & easier(bees pollinate crops)
Islands closer to the “mainland”
support more species
Cultural
Money generate by recreation (parks, camping, tours) or scientific knowledge
Human activities ….
disrupt the ability of ecosystems to function, which decreases the value of ecosystem services they provide
Overfishing leads to
fish pop. collapse (lost fishing jobs and lower fish sales in the future)
Clearing land for ag./cities removes trees that store CO2 (more CO2 in atm.=
more CC = more storm damage & crop failure)
Zone of physiological stress
range where organisms survive, but experience some stress such as infertility, lack of growth, decreased activity, etc.
Larger Islands support ..
more total species
Zone of intolerance:
range where the organism will die
Ex: thermal shock, suffocation, lack of food/water/oxygen
Natural Disturbances
natural event that disrupts the structure and or function of an ecosystem
Ex: Tornados, hurricanes, asteroids, forest fires, drought
Episodic
occasional events with irregular frequency (ex: hurricanes, droughts, fires)
Ecological Range of Tolerance
Range of conditions such as temperature, salinity, pH, or sunlight that an organism can endure before injury or death
Optimal range:
range where organisms survive, grow, and reproduce
Periodic
occurs with regular frequency (ex: dry-wet seasons)
Random:
no regular frequency (volcanoes, earthquakes, and asteroids)
Natural Climate Change
Earth’s climate has varied over geologic time for numerous reasons
Ex: Slight changes in earth’s orbit & tilt cause mini ice ages & warmer periods as earth shifts slightly closer to & further from sun
Also due to climate change,
Sea level has varied over geological time as glacial ice on earth melts & forms
Migration
Wildlife may migrate to a new habitat as the result of natural disruptions
Ex: wildebeests migrating to follow rain patterns of African savanna
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 env. survive and reproduce more offspring
Evolution
Individuals with adaptations pass them on to offspring & individuals without adaptations die off, which leads to the entire population having the adaptation over time
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 env. changes, the less likely a species in the env. will be to adapt to those changes
If the pace of env. change is too rapid, many species may migrate out of the env. or die-off completely
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
Moss & lichen spores carried by the wind grow directly on rocks, breaking them down to form soil
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
Grasses, sedges, wildflowers, and berry bushes have seeds dispersed by wind or animal droppings
Stages of Succession
Stages are characterized by which types of plant species dominate the ecosystem; different species are adapted to the conditions of the different stages
Pioneer or early succession species
appear first, when the ground is simply bare rock, or bare soil after a disturbance
Characteristics of Pioneer or early succession species
seeds spread by wind or animals, fast growing, tolerant of shallow soil and full sunlight
moss, lichen (bare rock) | wildflowers, raspberries, grasses/sedges
Mid-successional species
appear after pioneer species have helped develop deeper soil with more nutrients by their cycles of growth/death
Late successional or climax community species
appear last, after soil is deepened and enriched with nutrients by cycles of growth and death by early & mid successional species
Characteristics of Mid-successional species
relatively fast growing, larger plants that need deeper soils with more nutrients than pioneers, sun tolerant
shrubs, bushes, fast-growing trees like aspen, cherry, and pine
Characteristics of Late successional or climax community species
large, slow-growing trees that are tolerant of shade and require deep soils for large root networks
Ex: maples, oaks, other large trees
