Unit 12 #2 - Ecosystems

Question 1

List populational levels in order

Answer 1

population, species, community, ecosystem, biosphere

Question 2

Every populational level is an emergent property of the level below it or above it?

Answer 2

Below it

*emergent properties: properties found in the whole but not in individuals alone (the whole is greater than the sum of the parts)

Question 3

What does genetics explain

Answer 3

how chemicals are organised into a living

organism, and how this information is transmitted.

Question 4

What does evolution explain

Answer 4

how selection operates on genetic
variation within populations, so that populations adapt to the
biotic and abiotic elements of their environments

it is seen in genes, populations, species and communities

Question 5

What does ecology explain

Answer 5

how the environment is determined by the

interactions between its living and non-living components.

Question 6

Name an exmaple of geological phenomenon created and maintained by a living ecosystem

Answer 6

Soil

In fact, some cliffs are formed of crushed shells of mollusks

Question 7

What is an ecosystem

Answer 7

Interaction between a community (biotic) and abiotic factors in the environment

Question 8

Name 2 things an ecosystem needs and how they relate to one another

Answer 8

1. Energy: solar (photoautotrophs) or chemical (chemoautotrophs), it enters from space and leaves by heat radiation though the food chain
2. Matter : N, P, C, H2O…, it cannot enter or leave earth so it circulates through biochemical cycles

Link between both: energy is needed, ultimately from the sun to move matter around and transform it

Question 9

What are the 2 laws of thermodynamics and their link to chemical transformations of life processes involving energy transfer?

Answer 9

1st law: energy cant be created or destroyed
2nd law: total entropy of universe must increase

there is flow of energy from sun to earth to space as heat

This is because energy is used to organize matter in an open system, but heat is lost at each energy transfer because of 2nd law

Question 10

How does lavoisier’s principle apply to matter

Answer 10

Conservation of mass: matter on earth stays on earth (closed system)

Question 11

In a food web, what does the arrow point

Answer 11

the consumer (from the consumed)

The arrow shows energy flow

Question 12

What is biomass and its main component

Answer 12

The total mass of organisms in a given volume or area

Its main component is carbon (ie we have lots of carbon)

Question 13

What is productivity

Answer 13

the amount and rate of production
which occur in a given ecosystem
over a given time period.

It is either dry matter or energy produced per area per time.

Question 14

What is the difference between primary and secondary productivity

Answer 14

Primary productivity: biomass of autotrophs produced

Secondary productivity: biomass of heterotrophs produced

Question 15

What is the percent loss of energy from solar energy to heat

Answer 15

99%, so 1% to primary producers

Question 16

What is the percent energy transferred from one trophic level to the next

Answer 16

10%

Question 17

How do zooplankton and phytoplankton relate

Answer 17

zooplanktons are heterotrophs that eat phytoplankton, a photoautotrophs

Question 18

detritivores

Answer 18

eat dead organic matter

Question 19

Decomposers

Answer 19

break down non-living organic molecules to smaller molecules: take carbs., nucleic acids, lipids, proteins and breaks them down into CO2, CH4, NH3

Question 20

How are pyramids of energy flow, biomass and numbers alike

Answer 20

all have first-level carnivores on top , but fewer, and shows that organisms are being eaten as fast as they are being produced (biomass=numbers)

Question 21

What is the difference between a top-down trophic cascade and a bottom-up trophic cascade

Answer 21

A bottom-up trophic cascade can happen if the primary producers
are eliminated or greatly reduced ie draves killed aquatic vegetation

Question 22

Biomagnification

Answer 22

subsatnces such as pesticides and mercury stored in tissues get concentarted in tissues of animals up the food chain becasue they eat all the pther animals that have fewer conenctrations within them ie belugas st-lawrence lots of mercury

Question 23

Does microplastics biomagnify

Answer 23

No, but the toxins they absorb do! The microplastics are ingested by animals in water

Question 24

Anthropocene

Answer 24

current geological age seen in segmentation rocks that is more compressed

Question 25

Draw the nitrogen, phosphorus, water and carbon cycle

Answer 25

notes

Question 26

Denitrifying bacteria

Answer 26

use nitrate as a source of energy, producing acid and

removing nitrogen from the soil

Question 27

What allows nitrogen fixation (N2 to NH3)

Answer 27

nitrogen fixing bacteria in soil (rhizobium), cyanobacteria in water, symbiotic relationship with plants that gives rhizobium low o2 environment for fixation in exchange for nitrates.

Question 28

What is the ammonification step of the nitrogen cycle

Answer 28

Nitrogen is excreted from organisms as urea, uric acid or ammonia (organic N to NH3) ie bird crystalize water to uric acid

Question 29

How do plants in low nitrogen soils get their nitrogen

Answer 29

become carnivorous ie pitcher plants trap flies or symbiotic relationship with nitrogen fixing bacteria ie alder trees

Question 30

name 4 sources of nitrogen

Answer 30

biological fixation, lightning (energy breaks down strong triple N2 bond), fossil fuels and nitrogen fertilizers

Question 31

What is eutrophic

Answer 31

increase level of nitrogen and phosphorus which reduces oxygen and prevents organisms apart form cyanobacteria of living

Question 32

What is oligotrophic

Answer 32

decrease levels of nitrogen and phosporus, which increases o2 and leads to many organisms being alive in these clear lakes.

Question 33

What did Hubbard Brook’s experiment show

Answer 33

If no trees on 2 mountains side to side: eutrophication between, erosion, flooding

Question 34

How does acid rain occur

Answer 34

burn fossil fuels, becomes sulfuric acid in atmosphere which acidifies the soil when it rains and kills organisms excpet denitrifying bacteria (removes nitrogen) so: acidic and nutrient-poor soil

Question 35

Name 4 greenhouse gases

Answer 35

CO2, CH4, N2O and O3

Question 36

What is produced by bacterial decomposition in low o2 and wet conditions

Answer 36

oil, coal, ch4 (by methanogens) and peat (by methanogens)

Question 37

What does cyanobcteria produce and what did it lead to in terms of the atmosphere

Answer 37

Cyanobacteria produces o2 so atmosphere is now an oxidising atmosphere