B3

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What is a species?
A group of organisms that can breed together to produce fertile offspring.
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How does adaptations affect species?
They make individuals of a species more likely to survive and go on to produce fertile offspring. It is then more likely the whole species continues to exist.
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How is a cactus adapted to the hot dry desert conditions?
It has a rounded shape (small surface area compared to volume, reduces water loss), thick waxy layer (reduced water loss), thick stem (store water), shallow extensive roots (water absorbed quickly over a large area).
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How is a fish adapted to the aquatic conditions?
Gills (extract oxygen from water), tail fins with a larger surface area (propel through water), streamlined bodies ( move through water with little resistance).
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How is variation caused?
Genetic (mutations), outside factors (radiation/chemicals) and mistakes (genes are copied in cell division).
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Describe natural selection
Individuals compete for limited resources - some survive.Some varieties have a better chance of survival and the characteristic that helps them survive is passed on. 'Best' features are naturally selected and species is more adapted to environment.
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What evidence is there for evolution?
Fossil records (shows species getting more and more complex) and DNA (Similarities and differences)
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How did Charles Darwin come up with his theory of evolution by natural selection?
By making many observations of organisms and applying creative thought to his findings.
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What did Lamarck argue?
If a characteristic was used a lot by an animal then it would become more developed. Reckoned thes acquired characteristics could be passed on to offspring
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Why was Lamarck's theory rejected in favour of Darwin's?
People eventually 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 does biodiversity include?
The number of different species on Earth, the range of different types of organisms and the genetic variation between organisms of the same species.
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Why is maintaining biodiversity important?
More plants are available so theres more resources for developing new food crops. When a living organism ecomes extinct, the unique chemicals it produces are no longer available.
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What suggests a lot of extinction id due to human activities?
There is a correlation between the growth of the world's population and the number of species extinctions.
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How do scientists group organisms together?
According to similarities in their characteristics, their genetics and the physical features they have.
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What are the five different kingdoms?
Bacteria, Fungi, Algae, Plants and Animals.
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Why is classification useful?
It shows us the evolutionary relationship between different organisms
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What changes can cause extinction?
The environmental conditions change and the species can't adapt to the change. A new species is introduced which is a competitor, disease organism or predator of that species. An organism in its food web that it is reliant on becomes extinct.
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Why do you hardly ever get food chains with more than about five stages?
So much energy is lost at each stage that there's not enough left to support more organisms.
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How can you calculate the efficiency of energy transfer?
Energy available to the next stage (divided by) energy that was available to the previous stage X100%
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What is the carbon cycle powered by?
Photosynththesis
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What happens when plants and animals decompose?
They are broken down by microorganisms and the decomposers release carbon dioxide back into the air.
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Why can't nitrogen from the atmosphere be used directly by plants or animals?
It's very unreactive
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What is nitrogen fixation?
The process of turning N2 from the air into nitrogen compounds in the soil which plants can use.
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What are the two ways nitogen fixation happen?
Lightning and Nitrogen-fixing bacteria in roots and soils.
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What is the role of decomposers?
They decompose proteins and urea and turn them into ammonia.
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What is the role of nitrifying bacteria?
They turn ammonia in decaying matter into nitrates (nitrification).
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What is the role of denitrifying bacteria?
They turn nitrates back into N2 gas which is of no benefit to living organisms.
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What are the three non-living indicators you can use to measure environmental change?
Temperature, Nitrate level and Carbon dioxide level.
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What living indicators can you use to measure environmental change?
Lichen (sulfur dioxide in atmosphere), Mayfly Nymphs (oxygen in water), and Phytoplankton (indicate water pollution - nitrates and phosphates, known as algae bloom).
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What does sustainability mean?
Meeting the needs of today's population without harming the environment so that future generations can still meet their own needs.
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What is an important part of sustainability?
Maintaining biodiversity.
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How can the sustainability of using packaging materials be improved?
Using renewable materials, using less energy, use less packaging material and creating less pollution by using biodegradeable materials.
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Other cards in this set

Card 2

Front

How does adaptations affect species?

Back

They make individuals of a species more likely to survive and go on to produce fertile offspring. It is then more likely the whole species continues to exist.

Card 3

Front

How is a cactus adapted to the hot dry desert conditions?

Back

Preview of the front of card 3

Card 4

Front

How is a fish adapted to the aquatic conditions?

Back

Preview of the front of card 4

Card 5

Front

How is variation caused?

Back

Preview of the front of card 5
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