B3 - Life on Earth

  • Created by: StudentAM
  • Created on: 30-04-17 21:08
What are species?
is a group of organisms that can breed together to produce fertile offspring
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Living organisms adapting to their environment increases what?
increases the species’ chance of survival by making it more likely that individuals will survive to reproduce
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What do living organisms depend on for survival?
the environment and other species
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Where are competitions for resources?
between different species of animals or plants in the same habitat
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What happens when their are changes in a food web?
impact on other species that are part of the same food web
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What is interdependence?
when all the organisms in a food web are dependent on other parts of the web
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Give examples of changes in the environment that may cause a species to become extinct.
the environmental conditions change beyond its ability to adapt, a new species that is a competitor, predator or disease organism of that species is introduced, another species (animal, plant or microorganism) in its food web becomes extinct
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Nearly all organisms depend on what for energy?
the sun.
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What do plants absorb for the process of photosynthesis?
sun's energy
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Where is this energy stored in the plant?
is stored in the chemicals which make up the plants’ cells
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When is energy transferred between organisms in an ecosystem?
when organisms are eaten, when dead organisms and waste materials are fed on by decay organisms (decomposers and detritivores)
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How does energy pass out of a food chain at each stage?
via heat, waste products and uneaten parts, limiting the length of food chains
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How do you calculate percentage efficiency of energy transferred?
Percentage of energy successfully transferred = (Amount used)/(Amount potentially available) ×100
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How is carbon recycled through the environment (CARBON CYCLE)?
[DRAW CYCLE] processes of combustion, respiration, photosynthesis and decomposition
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What is the importance of microorganisms in the carbon cycle?
they break down the remains of dead plants and animals and, in doing so, release carbon dioxide through respiration.
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How is nitrogen recycled through the environment (NITROGEN CYCLE)?
[DRAW CYCLE] nitrogen fixation to form nitrogen compounds including nitrates, conversion of nitrogen compounds to protein in plants and animals, transfer of nitrogen compounds through food chains, excretion, death and decay of plants and animals, etc
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What is the importance of microorganisms in the nitrogen cycle?
[CYCLE] decomposition, nitrogen fixation and denitrification
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How can environmental change be measured?
[SEE SHEET] Non-living indicators: nitrate levels, temperature, carbon dioxide levels. Living indicators: phytoplankton, lichens, aquatic river organisms (mayfly nymphs)
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Approximately when did Earth begin?
3500 million years ago
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What has happened in life of Earth, including species that are now extinct?
evolved from very simple living things
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Where does variation take place, and what happens?
between individuals of the same species and that some of this variation is genetic so it can be passed on to offspring
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What is caused when mutations take place in genes?
genetic variation
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What happens when mutated genes in sex cells are passed on?
passed onto offspring and could produce new characteristics
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What is natural selection?
The genetic variation between individuals in a species with characteristics that improve chances of survival are more likely to live to adulthood. When these individuals reproduce, they pass on the beneficial characteristics to offspring [NATURAL]
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What is selective breeding?
Where animals and plants with certain traits are deliberately mated together to produce offspring with certain desirable characteristics. This could be used to create new varieties of organisms or to increase the yield of animals and plants [HUMANS]
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What can the combined effect of mutations, environmental changes, natural selection and isolation do?
produce new species in the process of evolution
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What is the evidence for evolution?
[SEE SHEET] the fossil record and from analysis of similarities and differences in the DNA of organisms
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What is Darwin’s theory of evolution and what did it lead to?
evolved by natural selection, was the result of many observations and creative thought
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Why is Darwin's theory a better scientific explanation than Lamarck’s?
fits with advances in understanding of genetics, no evidence or mechanism for Lamarck's inheritance of acquired characteristics
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How are organisms classified?
into groups according to similarities and differences in characteristics (physical features, DNA)
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How are organisms classified at different levels?
from large groups containing many organisms with a small number of characteristics in common (e.g. kingdom) to smaller groups containing fewer organisms with more characteristics in common (e.g. species)
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What can classification of living and fossil organisms help to do?
make sense of the enormous diversity of organisms on Earth, show the evolutionary relationships between organisms
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What does Biodiversity refer to?
the number of different species, the range of different types of organisms, e.g. plants, animals and microorganisms, the genetic variation within species
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why is biodiversity important for the future?
for the development of food crops and medicines
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Why is the rate of extinction increasing and is mainly due to what?
human activity - excessive hunting of animals, deforestation.
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What does sustainability mean?
meeting the needs of people today without damaging the Earth for future generations
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What is one of the keys to sustainability
maintaining biodiversity to ensure the conservation of different species
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What is monoculture and why it's not sustainable?
a single variety of a crop, the technique was not sustainable because it reduced biodiversity affecting the whole food chain
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How can sustainability be improved?
packaging materials, by considering the materials used, energy used and pollution created
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Why is it preferable to decrease the use of some materials, even when they are biodegradable?
because of the use of energy in their production and transport, and slow decomposition in oxygen deficient landfill sites
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Other cards in this set

Card 2


Living organisms adapting to their environment increases what?


increases the species’ chance of survival by making it more likely that individuals will survive to reproduce

Card 3


What do living organisms depend on for survival?


Preview of the front of card 3

Card 4


Where are competitions for resources?


Preview of the front of card 4

Card 5


What happens when their are changes in a food web?


Preview of the front of card 5
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