ecology and its impacts

Question 1

producer def

Answer 1

carries out photosynthesis by using chlorophyll to absorb light energy and produce glucose in the presence of co2 and water. light energy is converted to chemical energy and stored in glucose molecules

Question 2

consumer def

Answer 2

needs to feed on other organisms to obtain energy in the form of organic molecules

Question 3

uses of the energy

Answer 3

humans -> respiration
animals -> lost through egestion of faeces, excretion of urea, through heat during respiration, to keep warm, cotractions of muscles for movement, trnasmit nerve impulses, movement and tranport of materials
producer -> synthesis protoplasm, energy required for roots to absorb mineral ions through AT, fome loght energy from sun reflected off thesurface of leaves

Question 4

source where prpducer gets its energy

Answer 4

sun

Question 5

types of consumers

Answer 5

primary(herbivores), secondary(carnivores), tertiary(animals thta feed on other carnivores)

Question 6

what are decomposers

Answer 6

• obtain energy frombreaking down dead organisms, faeces and excretory products
• releases inorganicnutrients for nutrient cycling (carbon and nitrgoen)
• e.g abcteria, fungi, earthworms

Question 7

food chains

Answer 7

producer -> primary consumer -> secondary producer -> tertiary consumer
shows the feeding r/s

Question 8

trophic level

Answer 8

generally not more than 4 trophic levels
each level or organism in a chain

Question 9

food web

Answer 9

interlinked food chains

Question 10

non-cyclic energy flow in an ecosystem

Answer 10

• light energy from sun converted into chemical energy via photosynthesis in plants
• 10% ernergy from prducers passed from one trophic level to anither via feeding as 90% is lost as heat throguh respiration
• the flo of energy in the ecosystem is non-cyclic
• energy is lost to the envt as heat as it flos throguh the ecosystem
• dead org and egested and excreted materials contain trapped chemical energy
• energy lost in uneaten body pars, faeces and excretory products -> released via decomposers but they use some this energy for their own needs but the rest released to envt

Question 11

why there must be short food chains

Answer 11

• 90% of energy is lost from each trophic level to the next
• energy lost through egestion of faeces, excretion of urea, throguh heatduring respiration
• other organisms in high trophic levels will get little energy that is insufficient to sustain life

Question 12

pyramid of numbers

Answer 12

• allows the comparison of organisms in e/ trophic level at a particular gime
• can be inverted if organisms at one trphic kevel are parasitic on organisms of anotehr trophic leve;
• can be inverted if many small org feed ona large org

Question 13

pyramid of biomass

Answer 13

• allows the comparison of dry mass of organis present at e/ trophic level at a partiular time
• typically pyramid shpaed
  -can be weirdly shaped if org on one trophic level have high reproductive rates
• a non pyramid shaped pyramid of biomass doesnt take into account the rate of repro, is based on standing mass,
• e.g. for phytoplankton -> zooplankton -> small fish -> large fish
  zooplankton biomass larger than phyto bc of phyto high repro rates so ca repace those that were eaten v fast -> can support zooplank

Question 14

how to obtain info for pyrami of biomass

Answer 14

• collect all organisms at each trophic level
• dry them in an oven until at xonstant mass is obtained
• weigh them

Question 15

carbon cycle

Answer 15

• The carbon in a glucose molecule in the body of an animal can be passed from one organism to another through feeding in the food chain/food web.
• Some of the glucose will be oxidised to release energy during respiration and carbon is released to the atmosphere as carbon dioxide.
• When organisms died, the decomposers break down dead organic matters and release co2, anda also use the organic molecules for their respiration and carbon is also released to the atmosphere as carbon dioxide.
• Carbon dioxide in the atmosphere is taken in by producers which will use the carbon dioxide and water to synthesis glucose in the presence of light absorbed by chlorophyll and light.
• The carbon in the glucose is cycled in the food chain again when the producers are consumed by another organism.

Question 16

what is carbon sink

Answer 16

natural r artificial reservoir that accumulates and stores some carbon containing chemical compounds for an indefinite period
stores more carbon than it releases

Question 17

types of carbon cycle - natural - oceans

Answer 17

➢phytoplankton use dissolved carbon dioxide, nitrogen phosphorus (P), and other trace elements (barium, iron, zinc, etc.) during photosynthesis to make carbohydrates, lipids,
and proteins.

➢Some plankton combine calcium and dissolved carbonates
(carbonic acid and bicarbonate) to form a calcium carbonate
protective coating.

➢some carbon compounds found in oceans is buried in the seabed
in the form of fossil fuels such as natural gas and oil

Question 18

carbon sinks - natural - forest

Answer 18

➢absorption of atmospheric carbon dioxide by plants in forests for photosynthesis

➢large amount of carbon compounds are stored in the trees

➢carbon is also stored in the soil as dead organic matter

➢when trees die, their remains may be buried deep under the
ground and under high pressure and over millions of years,
these remains form coal (fossil fuel)

Question 19

efefts of pollution due to sewage

Answer 19

1) eutrophication
Large release of nitrates and phosphates from decomposition of sewage
Which are absorbed by algae + used in the synthesis of of algal aa
Which promote their growth thus causing a rapid increase in their population
R: sewage contains a lot of phosphates and nitrates

Algal cover reduces light penetration into pond water
Pond producers are not able to photosynthesise efficiently
Produces decrease in population
Causing interruption to energy flow in food chains + fish to die
Waste discharge causes explosion in bacteria/decomposer population in pond
Which competes with fish for oxygen causing fish to suffocate and die
Waste discharge might contain toxins which kill fish

2) health risks
agriculture - significant health hazards related to using water loaded with pathogens in this way, especially raw vegetables that have been irrigated with the polluted water e.g. Escherichia coli (E. coli) in human and animal faeces causes food poisoning and even death

Question 20

effects of pollution due to inorgnaic waste

Answer 20

• mercury, lead
• mercury poisoning

Question 21

effects of pollution due to insecticides including bioaccumulation up food chains and impact on top carnivores

Answer 21

1) bioaccumulation and bioamplification
Mercury is non-biodegradable and insoluble in water + it is not excreted and is stored in the tissues of organisms that consume it.
When consumers keep on consuming food containing mercury, the concentration further increases in the bodies and this is known as bioaccumulation.
As the organisms are eaten along the food chain, the mercury is passed along the food chain, increasing the mercury concentration in the bodies of organisms along the trophic levels. This is known as bioamplification.
2) agricultural impacts
indiscriminate use of insecticides leads to decrease in population of pollinators such as honey bees
this causes reduction of crop production
insecticides may become ineffective after some time as some insects may develop resistance to them.

Question 22

diff btwn bioaccu and bioampli

Answer 22

• bioaccu - when certain chemicals are not excreted but accu in org body
• biampli/mag - when cjhemicals are passed alog the food chain, increasing conc in bodies of org along food chain

Question 23

outline the roles of microorganisms in sewage treatment as an example of environmental biotechnology

Answer 23

• microoorganismshelp in decomposition of complex irgamic molecules into smaller molecules
• adv : activated suldge can be recycled

Question 24

discuss reasons for conservation of
species with reference to the
maintenance of biodiversity and how this
is done,

Answer 24

1. To maintain biodiversity by preventing the extinction of species
   * Maintenance of a large gene pool is important as many wild plants and animals possess favourable
   genes. By cross-breeding the different varieties of wild plants and animals, we can improve
   agricultural produce. For example, plants with better resistance to diseases and drought can be
   produced by crossing domestic species with wild species.
   * Many tropical plants are of great importance as they are sources of medicinal drugs. Examples
   include quinine, an anti-malarial drug from the bark of Cinchona, and vinblastine, a drug used to treat
   leukemia (a type of cancer) derived from the Madagascar rosy periwinkle. Many more medicinal
   drugs in plant species remain to be discovered.
2. For scientific research:
   The study of wildlife provides useful information to humans. For example, we learn about evolution
   from studying wildlife.
3. For economic purposes
   * Marine life needs to be conserved as they are a major source of human food.
   * Tropical rainforests also provide food. Rice, pineapple and banana are some examples
   of food plants that were developed from rainforest plants.
4. To maintain a stable and balanced ecosystem
   This prevents disruption of natural cycles such as carbon cycles, and also prevents global warming.
5. To preserve natural scenery and wildlife for people to appreciate
   Natural resources enable outdoor recreational activities such as fishing, hiking and skiing.

acheiveed throguh management of fisheries and timber production

itshabitat, may kill animals libving there, loss of biodiverit, may be a food source, deforetion burning of trees release co2 into atmosphere, loss of flora and fauna wd disrut natural cycles like he carbion cycle

Question 25

in sewage disposal, what are the results of processes that involve aerobic microorganisms and of processes that involve anaerobic microograjisms

Answer 25

reuskts of aerobic respiration - co2 and water produced

resukts of anaerobic processes - methane produced

Question 26

why cannot let the top predator die

Answer 26

top predtaor mainatims the ecological baalnace of the ecosystem by keepingbthe population of thiebr prey in check

Question 27

methane to co2?

Answer 27

combustion