B3 Revision

what is a species
a group of organisms that can breed together to produce fertile offspring
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Name 3 features of a Cactus that show its adapted to its environment
round shape giving them a small surface area to reduce water loss. leaves reduced to spines to reduce water loss. store water in thick stem to store water.
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what is natural selection?
resources that are needed to survive are limited, individuals must compete for these resources to survive.some species have a better chance of survival this means they have an increased chance of reproducing. species is more adapted to environment.
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what is selective breeding?
humans deliberately choose a feature they want to appear and only breed these animals or plants. this doesn't help survival instead it may make more money.
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what is the difference between natural selection and selective breeding?
in natural selection the features are naturally selected and help it to survive. in selective breeding the humans choose the features they want and it doesn't help survival.
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what is variation?
when two of the same species don't look alike caused by genetic variation which is passed on, this is when genes change = mutations. mutations can be caused by outside factors like radiation or chemicals and mistakes in cell division.
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what can mutations in sex cells cause?
they can cause offspring to develop new characteristics, some can be harmful to the organism and some may help it to survive.
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what can mutations in body cells cause?
they have little or no effect though they can lead to cancer
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what have living things evolved from and what have they become?
living things have evolved from being very simple to become more complex and varied
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how can the process of evolution produce new species?
sometimes groups of organisms can become isolated from each other mutations then create new feature on the organisms, if they are of benefit natural selection causes them to spread through populations and environmental changes give them diff adaption
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what was Charles Darwins theory and how did he come up with this?
theory of evolution by natural selection which he came up with by making many observations and applying creative thought to his findings
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what was Lamarcks theory?
if a characteristic was used a lot it would become more developed and these acquired characteristics would be passed onto the offspring
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why was Lamarcks theory rejected?
people concluded acquired characteristics don't have a genetic basis so they're unable to be passed on to the next generation
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what is biodiversity?
the variety of plant and animal life in the world e.g species, range of diff organisms, genetiv variation between them
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why is maintaining biodiversity important?
the more plants we have available the more resources there are for developing new food crops. new medicines have also discovered using using chemicals produced by living things. if an animals becomes extinct these unique chemicals are no longer avail
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what does classification show us?
the evolutionary relationships between different organisms.
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what factors are essential for life?
light( for plants to make food). food and minerals. oxygen. carbon dioxide (for plants) water.
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what is interdependence?
when organisms rely on each other
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name 3 changes that can cause extinction in the environment ?
environmental changes (the species cant adapt). a new species is introduced which is a competitor or a predator. an organism in its food web becomes extinct.
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what is the source of energy for almost all life?
the sun
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what percentage of light energy to plant use
a small amount
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how is energy transferred through an ecosystem?
when they get eaten
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how is energy lost?
respiration, movement, heat, waste products, uneaten part eg. bones
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how to work out the efficiency of energy transfer
energy available to the next stage / energy that was available to the previous stage X 100
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non living indicators of environmental change
temperature- taken over a long period of time could indicate climate is changing. Nitrate level - an increase of nitrate in water suggests its polluted. Carbon dioxide level- global warming
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living indicators of environmental change
Lichen- air is clean lots of lichen sensitive to sulfur dioxide, Mayfly Nymphs- water is clean sensitive to oxygen. phytoplankton- if water is polluted
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how can packaging material be made more sustainable?
using renewable materials: paper + card. recycling produces less energy. using biodegradable materials = rot easily. use less packaging
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Other cards in this set

Card 2

Front

Name 3 features of a Cactus that show its adapted to its environment

Back

round shape giving them a small surface area to reduce water loss. leaves reduced to spines to reduce water loss. store water in thick stem to store water.

Card 3

Front

what is natural selection?

Back

Preview of the front of card 3

Card 4

Front

what is selective breeding?

Back

Preview of the front of card 4

Card 5

Front

what is the difference between natural selection and selective breeding?

Back

Preview of the front of card 5
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