Unit 7: Ecosystems

Question 1

what is an ecosystem

Answer 1

• an assemblage of many variables that function independently yet in concert that contain biotic and abiotic components

Question 2

what is the relationships between ecosystem stability adn biodiversity (remember the diagram)

Answer 2

• diverse ecosystems are more stable than less diverse communities because risk is spread over the entire biological community,
• they are also more productive to an extent
• there is a max function that will not increase even if biodiversity increases

Question 3

decomposers are an important biotic component of ecosystems why

Answer 3

• decomposers are final link in chain and renew entire system by breaking down organic material
• is how ecosystems can recycle themselves to keep moving forward

Question 4

what is the difference between primary and secondary succession

Answer 4

• primary succession: occurs from bare rock or a disturbed site with no evidence of a former community
• secondary succession: occurs if some aspects of a functioning community are present

Question 5

why are forest fires good?

Answer 5

• release seeds that need heat to open
• allow for a new ecosystem
• good for several animals (moose, deer, bears, birds etc)
• forest rebound quite fast
• they are purposefully set in nature reserves

Question 6

how does fire effect succession

Answer 6

• succession often requires initiation of a disturbance (like a fire) to initiate new growth and development of a new ecosystem
• terrestrial succession (secondary succession) occurs is some aspect of a functioning community are present (like a fire)

Question 7

what happens to nutreints contained in a forest fire after

Answer 7

• a lot of seeds are opened after a fire
• chemicals elements recycle themselves over and over again in life processes
• some nutrients are compromised (N, P, S)
• but increases the availability for other nutrients (seeds open, more canopy light, release nutrients stored in the litter

Question 8

two disturbances that can affect succession in grasslands

Answer 8

• farming: only 1% of the tall grass remains, the rest has been either urbanized or tuned into farmland
• fire: fires destroy seed bans and later the seed bed can change

Question 9

what are the climate and vegetation characteristics of the wets coast temperature rainforests

Answer 9

• climate: high temperature and high precipitation (in the winter especially)
• vegetation: canopy is ominated by conifers and hardwood trees are common. lush and diverse understory of shurbs, ferns, moss, lichen, thick undergrowth

Question 10

what is the climate and vegetation characteristics of the boreal forest

Answer 10

• climate: -30 - 15 degrees. cold wet and col dryish. long winters and long days in the summer
• vegetation: conifers (needles) drought resistant, moderate photosynthesis rate, frozen ground limits water supply, few species and remarkably homogenous