APES Unit 2 Flashcards
3 levels of biodiversity
Ecosystem (habitat) diversity
Species diversity
Genetic diversity
Ecosystem resilience
How quickly a ecosystem can return to its original conditions after a major disturbance. Higher diversity means more resilience.
Habitat loss
biggest reduction in diversity. First affects species specialists then generalists.
Niche specialist
Specialized to live in a specific habitat. If environment changes disadvantaged. EX: pandas
Niche generalists
Species that can survive under a lot of conditions. Broad niche. Advantages when environment changes. EX: racoon
Bottleneck events
Bottleneck events randomly kill individuals regardless of their genes. reduce gene diversity.
Ecosystem disturbances examples (bottleneck event causes)
Wildfires, droughts, diseases.
The more genetically diverse a population is →
the more likely the pop. will survive a ecosystem disturbance.
Genetic diversity
how different the genes inside of individuals of the same species.
Ecosystem (habitat) diversity
How many habitats are available in a given area
more habitat diversity →
more organisms/species. Can support many microhabitats.
Microhabitat
Small area which differs from surrounding habitats.
Species diversity
Number of different species and balance of population size.
Species Richness
Total number of different species in an area.
Species evenness
measure of how the pop. in an ecosystem is balanced. Counts individuals.
more evenness =
more diversity
High richness is a
good sign of ecosystem health.
Evenness indicates
if there is a dominant species.
Ecological tolerance/ range of tolerance
EX.
range of abiotic conditions an organism can endure before injury or death. EX: temperature, salinity, pH, sunlight
Species and individual tolerance
Species will more be an average. Some individuals will always be able to withstand more extreme conditions than the rest due to genetic diversity.
Optimal range
Where organisms thrive. Survive, reproduce and grow.
Zone of physiological stress
Organisms can survive but under stress.
Zone of intolerance
Organisms die. Cannot survive in conditions.
Fundamental niche
the abiotic conditions under which a species theoretically can live under. (without competition)
Realized niche
The range of biotic and abiotc conditions under which a species actually lives. (with competition)
Ecosystem Services
Benefits provided to humans by healthy ecosystems
Provisioning services
Examples.
Physical good from nature that we can directly use.
Drinking water
Food
Wood for building or fuel
Medicine
Regulating services
Examples
Ecosystem processes that help regulate environmental conditions like climate.
Rainforest/ocean remove carbon
plants filter water and air
pollination
Cultural services
Examples
non-material benefits that contribute to human culture.
aesthetic value of nature
outdoor recreation
mental/physical well-being
Supporting services
Examples
Underlying natural processes that make it possible for the other processes to exist.
Soil formation
photosynthesis
habitat
cycles
Anthropogenic
Human caused
Human activities that disrupt the ability of ecosystems to function decr. the value of services.
Deforestation
Over-fishing/over-harvesting
water pollution
biogeography
study of ecological relationships and distribution of organisms on islands.
Real island
Island surrounded by water
habitat island
area different from surroundings EX parks
Sky island
Mountains with high peaks and therefore different climate
Larger islands support more total species.
Why?
Larger islands support more total species.
-more diff. ecosystems
-more niches available
-larger pop. size
-more food or habitat/species
-lower extinction rate.
Islands closer to mainland support more species.
Why?
Islands closer to mainland support more species. 2nd rule of biogeography.
-easier to colonize/get to
-more continual migration and colonizing organisms
Evolution on islands
Islands have limited resources so there is more pressure for species to adapt.
Adaptive radiation
Example-
a single species rapidly evolving into new species to use different resources. To reduce competition. EX Galapagos finches. Hawaiian honeycreepers
Natural Disturbances that disrupt the structure of an ecosystem
Examples
Natural event that disrupts structure or function of an ecosystem.
-tornadoes
-hurricanes
-forest fires
-drought
-asteroid
Natural Disturbances time frames
Periodic
Episodic
Random
Periodic time frame
Examples
Occurs with some regular frequency somewhat predictable. Ex. dry and wet seasons
Episodic time frame
Examples
Occasional events with irregular frequency. Not predictable. Some times of the year it is more likely to happen.
EX. Droughts, fires, hurricanes
Random time frame
Examples
No regular frequency. We understand why but not when.
Ex. Volcanoes, earthquakes, asteroids.
Natural climate change
Examples
Earth’s climate varies over time for many reasons that are natural.
Ex. -Slight change in orbit and tilt cause mini ice-ages and warm periods.
- sea levels rise and fall due to glaciers melting and forming.
Environmental Change=
habitat disruption
Sea levels rise →
Estuaries shift due to
Loose of coastal estuary habitats.
Sea levels rising change the habitats by increasing depth and salinity of water. Also flood inland habitats.
Estuaries shift due to high water.
Migration
Examples
Natural disturbances cause species to migrate, sometimes predictable and repetitive patters or less predictable.
Example: Wildebeest follow rain patterns in savanna.
Bird migration
Birds migrate due to insect births. Peak demand for bird hatchlings coincides with peak insect/caterpillar hatching
Resistance vs. Resilience
Resistance ability of an ecosystem to withstand a disturbance
Resilience is the ability to recover after a disturbance.
seed scarification
fire cracks open the seeds
Heat shocks
High temperatures to break dormancy of seeds.
Smoke stimulation
chemicals in smoke trigger germination.
Why do all populations have some genetic diversity?
Random mutations result in copying errors when copying DNA.
What are adaptations?
Adaptations are a trait the increases an organisms fitness.
What is organism fitness?
The ability to survive and to reproduce.
Natural selection
Species will have more offspring where individuals that are better adapted survive.
Individuals with adaptations
Evolution?
-Individuals with adaptations pass them on to offspring
-Individuals without adaptations die off leading to eventually the whole population having these adaptations. (Evolution)
selective pressure/force
Environmental condition that kills individuals without adaptation.
Selective pressure examples
-Predation
-lack of food
-Disease
Environmental change and evolution
the environment and habitat in which an organism lives in determines which traits are adaptations. These change if your habitat changes.
Evolution Peppered moths example
Peppered moths in England were mostly light in color. Because of the industrial revolution the trees in the forest turned darker, making dark moths less visible to predators giving them an advantage. Now all moths are dark.
Genotype
Phenotype
Genes
physical trait
Paces of evolution (3)
1) If envir. changes rapidly, you might not have time to adapt. Leading in migration or complete wipeout.
2) Lots of genetic diversity means better survival change.
3) longer life-span means slower evolution rate. EX bacteria evolve quickly humans don’t.
Ecological succession
gradual process of change in the structure of a community over time.
Changes in plant life →
leads to change in habitat
Primary succession occurs
example
occurs in area without previous plant life. EX: after volcanic eruption. BARE ROCK!
pioneer species in primary succession
How is soil formed?
moss and lichen
able to grow directly on rocks. initial soil is formed by chemical weathering of rocks.
Secondary succesion
occurs in an area WITH soil WITHOUT plant life. was removed by disturbance (fire, tornado, logging)
pioneer species secondary succession
grasses, wildflowers, weeds.
very small, fast growing plants.
stages of succession indicate
which plants dominate the ecosystem
Pioneer species (stages of succession)
Examples
pioneer species appear first.
-seeds spread quickly by wind or animals.
-fast growing, tolerant of full sunlight.
mid-successional species (stages of succession)
Examples
appear after pioneer species have developed soil.
-relatively fast growing
-larger plants need deeper soil
-sun tolerant
EX: shrubs, bushes, cherry, pine
late-successional species / climax community species (stages of succession)
Examples
need deep soil for root growth.
-large, slow growing trees
-tolerant of shade
-require deep soil of large network of roots
EX: maple, oak, other large trees
succession in aquatic ecosystems (lakes)
lakes fill with sediments over time and slowly become terrestrial biomes
sediments moved by wind, water, landslide
What increases over time as succession occurs?
biomass
species richness
NPP
key stone species
Example
play a more important role in community than their abundance says. MAINTAIN BIODIVERSITY
EX: sea otters
Trophic cascade
domino affect on the whole food web when keystone species are removed
trophic cascade example sea otter
sea otters live in kelp forests and they eat sea urchins. when otters are removed, sea urchins take over and eat all the kelp removing habitats for other species
ecosystem engineer and
Example
creates or provides habitats for other species EX: beavers building dams for other animals
indicator species
and example
indicate ecosystem health by reflected abiotic/biotic state of environment.
EX: Amphibians (frogs) are sensitive to pollution
EX: birds (canary) brought down into mines so if they die we know that the air quality is poor.
macro-invertebrates in rivers and streams
are indicators if water quality is good in streams and rivers. some animals are more pollution tolerant than others meaning that if the quality of water is bad, the intolerant die. (bio-indicators)
