Ecosystems Flashcards
(22 cards)
Ecosystem
Self sustaining association of living plants and animals and their nonliving physical environment
Open system where organisms are linked together by nutrient cycles and energy flows
Ecology and biogeography
The study of relationships between organisms and their environment
(Biogeography: study of geographical distribution of organisms)
Community
A group of species interacting with other organisms or the environment in a particular way (pollinators)
Habitat: type of environment that a certain community inhabits (water, soil)
Niche: function/role of a certain community or organism (“job”)
Ex: Bromeliad frogs - habitat = bromeliad, niche = predator
Plants
Producers
Link between solar energy and the biosphere
Physical structure of many habitats (forest)
Staple foods
Photosynthesis
The chemical reaction to unite CO2 (from the air) and hydrogen (from water), requires energy (light)
Traps the energy into food (sugars)
6CO2 + 6H20 + energy (light) –> C6H12O6 + 6O2
Chlorophyll
Green pigment that absorbs light
It reflects green and absorbs red/blue/violet
Respiration
Chemical reaction to convert food and O2 into usable energy
Releases CO2 and water as a byproduct
C6H12O6 + 602 –> 6CO2 + 6H20 + energy (heat)
Net primary productivity
The net photosynthesis of an entire plant community
Measured in fixed (chemically bound) carbon per square meter per year (C/m^2/yr)
Varies with light (latitude), precipitation, temperature, and soil
Abiotic components
Light
Temperature
Water
Climate
Life Zones
Different ecosystems/species when climbing up a mountain because traveling away from the equator
Oxygen and Carbon
Closely associated through photosynthesis, respiration, combustion, and decomposition
Nitrogen cycle
Nitrogen = 78% of atmosphere
Occurs in all organisms (DNA and RNA, amino acids, proteins)
N2 = strong triple bond, useless for organisms
Nitrogen fixing bacteria (legumes) can convert N2 into nitrates (NO3) and ammonia (NH3)
Producers
Biotic
Autotrophs: self-feeders
Fix CO2 and convert it into “food” (stored energy)
Plants
Consumers
Biotic
Heterotrophs: feed on others
Depend on producers
-herbivores: primary consumers, eat plants
-secondary consumers: eat primary consumers
-tertiary consumers: consume secondary/primary consumers
Decomposers
Biotic
Also heterotrophs
Feed on waste or decaying organic matter while releasing inorganic compounds and nutrients into ecosystems
Bacteria, fungi
Food webs: calories and krill
1000 calories in producer
100 calories in primary consumer
10 calories in secondary
1 calorie in tertiary
Producers: phytoplankton
Primary: krill/zooplankton
Secondary: seals, squid, whales
Tertiary: orcas, humans
Biodiversity
Variability among organisms of certain habitat or ecosystem
- taxonomic: species
- ecological: pollinators/predators
- morphological: size/color
- molecular: genetic variability f
Ecosystem stability and resilience
Stability: the ability to resist disturbances
Resilience: the ability to recover from disturbance
Ex: Reduced Impact Logging
- how much can be harvested = stability
- how soon is it ok to harvest again = resilience
Primary ecological succession
Beginning and development of an ecosystem, typically on new land surfaces (landslides, volcanoes)
Pioneer species: generalist, good dispersers and don’t need soil (lichens and moss)
Secondary succession
Occurs in a habitat already changed by primary succession
Requires soil and organic matter
Still generalist and tough species
Climax community
Complex and specialist species, theoretically stable
Fire ecology
Study and management of fire in natural habitats
Understanding fire regimes: frequency and intensity
Managing fires: suppression and prescribed burns
Total fire suppression in the early 20th century = fuel accumulation, even more catastrophic fires
