Ecosystems

Question 1

Ecosystem

Answer 1

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

Question 2

Ecology and biogeography

Answer 2

The study of relationships between organisms and their environment

(Biogeography: study of geographical distribution of organisms)

Question 3

Community

Answer 3

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

Question 4

Plants

Answer 4

Producers
Link between solar energy and the biosphere
Physical structure of many habitats (forest)
Staple foods

Question 5

Photosynthesis

Answer 5

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

Question 6

Chlorophyll

Answer 6

Green pigment that absorbs light

It reflects green and absorbs red/blue/violet

Question 7

Respiration

Answer 7

Chemical reaction to convert food and O2 into usable energy

Releases CO2 and water as a byproduct

C6H12O6 + 602 –> 6CO2 + 6H20 + energy (heat)

Question 8

Net primary productivity

Answer 8

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

Question 9

Abiotic components

Answer 9

Light
Temperature
Water
Climate

Question 10

Life Zones

Answer 10

Different ecosystems/species when climbing up a mountain because traveling away from the equator

Question 11

Oxygen and Carbon

Answer 11

Closely associated through photosynthesis, respiration, combustion, and decomposition

Question 12

Nitrogen cycle

Answer 12

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)

Question 13

Producers

Answer 13

Biotic
Autotrophs: self-feeders
Fix CO2 and convert it into “food” (stored energy)

Plants

Question 14

Consumers

Answer 14

Biotic
Heterotrophs: feed on others
Depend on producers
-herbivores: primary consumers, eat plants
-secondary consumers: eat primary consumers
-tertiary consumers: consume secondary/primary consumers

Question 15

Decomposers

Answer 15

Biotic
Also heterotrophs
Feed on waste or decaying organic matter while releasing inorganic compounds and nutrients into ecosystems

Bacteria, fungi

Question 16

Food webs: calories and krill

Answer 16

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

Question 17

Biodiversity

Answer 17

Variability among organisms of certain habitat or ecosystem

• taxonomic: species
• ecological: pollinators/predators
• morphological: size/color
• molecular: genetic variability f

Question 18

Ecosystem stability and resilience

Answer 18

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

Question 19

Primary ecological succession

Answer 19

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)

Question 20

Secondary succession

Answer 20

Occurs in a habitat already changed by primary succession
Requires soil and organic matter
Still generalist and tough species

Question 21

Climax community

Answer 21

Complex and specialist species, theoretically stable

Question 22

Fire ecology

Answer 22

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