Unit 19

Question 1

what is the principal source of energy

Answer 1

the sun

Question 2

describe the flow of energy

Answer 2

light energy is converted into chemical energy through photosynthesis
this energy is then transferred to animals through ingestion
when the animal dies, body is broken down by other organisms and the chemical energy is transferred back to the environment

Question 3

what does a food chain show

Answer 3

the transfer from one organism to another
begins with the producer

Question 4

what direction will the arrows in a food chain be

Answer 4

the flow of energy
(producer to consumer)

Question 5

what is a food web

Answer 5

a network of interconnected food chains

Question 6

what is a producer

Answer 6

an organism that makes its own organic nutrients(energy from sunlight) through photosynthesis

Question 7

what is a consumer

Answer 7

an organism that gets its energy from feeding on other organisms

Question 8

how can consumers be classed

Answer 8

primary,secondary,tertiary,quaternary

Question 9

what is a herbivore

Answer 9

an animal that gets its energy through eating plants

Question 10

what is a carnivore

Answer 10

an animal that gets its energy from eating other animals

Question 11

what is a decomposer

Answer 11

an organism that gets its energy from dead or waste organic material

Question 12

what happens when human overharvest organisms

Answer 12

the food web/chain becomes unbalanced

Question 13

what happens when foreign species are introduced to a habitat

Answer 13

can lead to extinction of native species
they die or are forced out

Question 14

what is the biomass of an organism

Answer 14

the total mass of its living material

Question 15

why are pyramids of biomass useful

Answer 15

they show how much energy is transferred and used by the organisms

Question 16

why is energy transfer between levels inefficient

Answer 16

only about 10% gets transferred and the other is used for life activities or heat loss

Question 17

why do food chains have less that 5 levels

Answer 17

since so much energy is lost, there is less and less at each level and it will so be minimal

Question 18

why is it more efficient for humans to eat crops

Answer 18

because less energy is lost than when humans eat livestock who eat crops

Question 19

what are the stages of the carbon cycle

Answer 19

photosynthesis, respiration, feeding, decomposition, formation of fossil fuels and combustion

Question 20

what is the photosynthesis stage of the carbon cycle

Answer 20

plants convert carbon dioxide into carbohydrates removing it from the atmosphere

Question 21

what is respiration in carbon cycle

Answer 21

the release of carbon back into the atmosphere

Question 22

what is feeding in carbon cycle

Answer 22

carbon moves along in the form of bio molecules in the food chain

Question 23

what is decomposition in carbon cycle

Answer 23

animals decompose when they die and carbon is released back into the earth

Question 24

formation of fossil fuels in carbon cycle

Answer 24

fossil fuels act as a source of carbon and are the main energy resource for many things

Question 25

combustion in carbon cycles

Answer 25

combustion of fossil fuels releases carbon dioxide back into the atmosphere along with the combustion of trees and plants

Question 26

what does nitrogen need to be changed into to be able to be used with living organisms

Answer 26

includes substances such as ammonium ions and nitrate ions

Question 27

what is nitrogen fixation and how does it occur

Answer 27

converts atmospheric nitrogen into substances which plants can absorb
happens through lightning and bacteria

Question 28

how does lightning work in nitrogen fixation

Answer 28

the energy of the lightning makes some nitrogen gas molecules combine with oxygen to create nitrogen oxides
these are washed into the soil to form nitrate ions

Question 29

how does bacteria work in nitrogen fixation

Answer 29

they live in soil and plants and convert nitrogen gas in the air between soil particles to ammonia
ammonia is later dissolved to form ammonium ions

Question 30

what do plants do in the nitrogen cycle

Answer 30

they absorb nitrate ions and use them to make amino acids and proteins

Question 31

how are the molecules passed along in the nitrogen cycle

Answer 31

through feeding in the food chain

Question 32

what is deamination in the nitrogen cycle

Answer 32

excess amino acids are transported to the liver for deamination where it is turned into urea and then urine
these are decomposed and form ammonium ions where they are absorbed by plants or denitrified to form nitrogen gas

Question 33

what is denitrification

Answer 33

nitrogen is reduced to nitrogen gas through denitrifying bacteria

Question 34

what is a population

Answer 34

a group of organisms of one species, living in the same area

Question 35

what is a community

Answer 35

the population of different species in an ecosystem

Question 36

what is an ecosystem

Answer 36

a unit containing the community of organisms and their environment

Question 37

how does food supply affect population growth

Answer 37

if theres large amount of food, population growth will be higher and vice versa

Question 38

how does predation affect population growht

Answer 38

if theres a lot of predators, growth will be slower

Question 39

how does diseases affect population

Answer 39

population will be reduced since organisms are being killed through disease
disease can spread quicker in densely populated areas

Question 40

what are the phases in a sigmoid curve

Answer 40

lag(first)
exponential(growth)
stationary(growth plateaus)
death(Resources run out and organisms die)

Question 41

what is nitrification

Answer 41

when ammonium compounds are turned into nitrocompounds so that they can be absorbed by plants

Question 42

how does nitrogen get transferred to animals

Answer 42

through eating
the nitrogen is turned into animal proteins