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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)
Biodiversity
diversity of lifeforms in an ecosystem; measured on all three different levels
Species richness
total number of different species found in an ecosystem.
Species Evenness
a measure of how all of the individual organisms in an ecosystem are balanced between different species.
“Bottleneck” Event
An environmental disturbance (such as a natural disaster or human habitat destruction) that drastically reduces population size and kills organisms, regardless of their genomes.
Bottleneck events do what
reduce genetic diversity, making them more vulnerable to future disturbances. The higher genetic diversity, the more resilient.
Inbreeding
when organisms mate with closely-related “family” members
Inbreeding Depression
Can lead to a higher chance of offspring having harmful genetic mutations, because they’re getting similar genotypes from both parents
Ecosystem Services
Goods that come from natural resources or services that ecosystems carry out that have measurable economic value to humans.
Provisioning
Goods taken directly from ecosystems or made from natural resources (wood, paper, food).
Ex: fish, hunting animals, lumber (wood for furniture/buildings) naturally-grown foods like berries, seeds, wild grains, honey
ex. of disruption: overfishing
Regulating
Natural ecosystems regulate climate and air quality, reducing storm damage and healthcare costs.
ex. Trees in a forest sequester (store) CO2 through photosynthesis, which reduces rate of climate change and lessens damage caused by rising sea level and reduces crop failure from drought
ex. of disruption: deforestation
Supporting
Natural ecosystems support processes that we do ourselves, making them cheaper and easier (ex. bees pollinate crops)
Ex. Bees and other insects pollinate our agricultural crops, leading to more crop production and higher profits
ex. of disruption: pollinator habitat loss
Cultural
Money generated by recreation (parks, camping, tours) or scientific knowledge
Ex. Beautiful landscapes draw tourists who pay to enter parks, spend money at local stores/restaurants, or pay camping fees
ex. of disruption: deforestation, land and water pollution, urbanization
Island Biogeography
The study of ecological relationships and community structure on islands
Rules of Island biogeography
1. Larger islands support more total species.
2. Islands closer to the “mainland” support more species.
Adaptive radiation
single species rapidly evolving into several new species to use different resources and reduce competition
(happens on islands because of limited space and resources, creating unique conditions for evolution and more pressure for species to adapt to narrower niches)
ex: Galapagos finches, beaks evolve to fit food
Ecological Range of Tolerance
Range of conditions (such as temperature, salinity, pH, or sunlight) that an organism can endure before injury or death result
Ex: salmon have a basic range of tolerance for temperature from 6o to 22o C, but some individual salmon have adaptations that give them a range of tolerance that is outside the basic range for the species.
Optimum 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 Disturbances
A natural event that disrupts the structure and or function of an ecosystem
ex: tornados, hurricanes, asteroids, forest fires, drought
periodic
occurs with regular frequency (ex: dry-wet seasons)
episodic
occasional events with irregular frequency (ex: hurricanes, droughts, fires)
random
no regular frequency (volcanoes, earthquakes, and asteroids)
Genetic diversity exists because:
Random mutations (while DNA is being copied) create new traits
Crossing over (during Prophase I of meiosis) creates new combinations of genes (and therefore, new traits)
Adaptation
a new trait that increases an organism’s fitness (ability to survive and reproduce)
Natural selection
organisms that are better adapted to their environment survive and reproduce more offspring.
Selective pressure (or force)
the environmental condition that kills off individuals without the adaptation
ex. a hawk eats all the mice that don’’t learn to hide from it until they’re all gone
The more rapidly an environment changes,
the less likely a species in the environment will be to adapt to those changes.
ex: if the ocean warms too quickly, many species of fish may not be able to migrate before they run out of oxygen and suffocate
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
ex. Moss and 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/clear-cutting) has cleared out the majority of plant life
ex. Grasses, sedges, wildflowers, and berry bushes have seeds dispersed by wind or animal droppings
Pioneer (or early succession species)
appear first, when the ground is simply bare rock after a disturbance
ex: moss, lichen (bare rock) → wildflowers, raspberries, grasses/sedge
Mid-successional species
appear after pioneer species have helped develop deeper soil with more nutrients by their cycles of growth/death
ex: shrubs, bushes, fast-growing trees like aspen, cherry, and pine
Late successional or 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
ex: maples, oaks, other large trees
“keystone” species
a species whose activities have a particularly significant role in determining community structure.
“indicator” species
a plant or animal that, by its presence, abundance, scarcity, or chemical composition, demonstrates that some distinctive aspect of the character or quality of an ecosystem is present
Invasive Species
not native to an area (often introduced unintentionally by human transport) and causing ecological distress.
Have no natural predators to control their populations
Are highly competitive for resources (i.e., aggressive feeders or fast growers)
Can thrive well in their non-native habitats
Have high biotic potential (growth rate) and low parental care
Are highly adaptable
Have diverse habitat and food needs
Control/Removal Methods
LEGAL: Laws preventing transport of invasives (firewood for emerald ash borers)
PHYSICAL: Careful boat cleaning and inspection (zebra mussels)
PHYSICAL: Removal (hunting pythons, detaching zebra mussels, pulling plants out, cutting trees down)
BIOLOGICAL: Introduction of natural predators
How Do Species Become Endangered?
Poaching, Invasives, Climate Change, Special habitat or food needs
CITES
“Convention on International Trade in Endangered Species of Wild Fauna and Flora”
international agreement for countries to set up agencies to monitor import and export of endangered species
Endangered Species Act
U.S. law giving USFWS power to designate species as endangered or threatened, monitor trade, and purchase land critical to these species’ habitats.
ICUN
Extinct, Threatened, Least Concern
Specialists
Most likely to be endangered or become extinct
Less likely to move to a new habitat
Less likely to adapt to new conditions
Disadvantaged by rapidly-changing habitat conditions
ex. panda
Generalists
Least likely to be endangered or become extinct
More likely to move to new habitat
More likely to adapt to new conditions
Advantaged by rapidly-changing habitat conditions
ex. raccoon
Habitat Fragmentation
the breaking of larger, continuous habitats into smaller, isolated patches; disrupts breeding, food webs and migration.
edge habitat
where two ecosystems such as forest/grassland or ocean/river (estuaries) meet, and has different characteristics than in the middle of each ecosystem
