Unit 19 Flashcards
what is the principal source of energy
the sun
describe the flow of energy
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
what does a food chain show
the transfer from one organism to another
begins with the producer
what direction will the arrows in a food chain be
the flow of energy
(producer to consumer)
what is a food web
a network of interconnected food chains
what is a producer
an organism that makes its own organic nutrients(energy from sunlight) through photosynthesis
what is a consumer
an organism that gets its energy from feeding on other organisms
how can consumers be classed
primary,secondary,tertiary,quaternary
what is a herbivore
an animal that gets its energy through eating plants
what is a carnivore
an animal that gets its energy from eating other animals
what is a decomposer
an organism that gets its energy from dead or waste organic material
what happens when human overharvest organisms
the food web/chain becomes unbalanced
what happens when foreign species are introduced to a habitat
can lead to extinction of native species
they die or are forced out
what is the biomass of an organism
the total mass of its living material
why are pyramids of biomass useful
they show how much energy is transferred and used by the organisms
why is energy transfer between levels inefficient
only about 10% gets transferred and the other is used for life activities or heat loss
why do food chains have less that 5 levels
since so much energy is lost, there is less and less at each level and it will so be minimal
why is it more efficient for humans to eat crops
because less energy is lost than when humans eat livestock who eat crops
what are the stages of the carbon cycle
photosynthesis, respiration, feeding, decomposition, formation of fossil fuels and combustion
what is the photosynthesis stage of the carbon cycle
plants convert carbon dioxide into carbohydrates removing it from the atmosphere
what is respiration in carbon cycle
the release of carbon back into the atmosphere
what is feeding in carbon cycle
carbon moves along in the form of bio molecules in the food chain
what is decomposition in carbon cycle
animals decompose when they die and carbon is released back into the earth
formation of fossil fuels in carbon cycle
fossil fuels act as a source of carbon and are the main energy resource for many things
combustion in carbon cycles
combustion of fossil fuels releases carbon dioxide back into the atmosphere along with the combustion of trees and plants
what does nitrogen need to be changed into to be able to be used with living organisms
includes substances such as ammonium ions and nitrate ions
what is nitrogen fixation and how does it occur
converts atmospheric nitrogen into substances which plants can absorb
happens through lightning and bacteria
how does lightning work in nitrogen fixation
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
how does bacteria work in nitrogen fixation
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
what do plants do in the nitrogen cycle
they absorb nitrate ions and use them to make amino acids and proteins
how are the molecules passed along in the nitrogen cycle
through feeding in the food chain
what is deamination in the nitrogen cycle
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
what is denitrification
nitrogen is reduced to nitrogen gas through denitrifying bacteria
what is a population
a group of organisms of one species, living in the same area
what is a community
the population of different species in an ecosystem
what is an ecosystem
a unit containing the community of organisms and their environment
how does food supply affect population growth
if theres large amount of food, population growth will be higher and vice versa
how does predation affect population growht
if theres a lot of predators, growth will be slower
how does diseases affect population
population will be reduced since organisms are being killed through disease
disease can spread quicker in densely populated areas
what are the phases in a sigmoid curve
lag(first)
exponential(growth)
stationary(growth plateaus)
death(Resources run out and organisms die)
what is nitrification
when ammonium compounds are turned into nitrocompounds so that they can be absorbed by plants
how does nitrogen get transferred to animals
through eating
the nitrogen is turned into animal proteins
