B2 Flashcards
List the order of the classification system which biologists use to sort organisms into groups.
Kingdom, phylum, class, order, family, genus and species.
In what ways are plants different to animals?
Plant cells have a cellulose cell wall. They use light energy to produce food by photosynthesis. Animals do not!
What two big groups are the animal kingdom split into?
Vertebrates (have a backbone) and invertebrates (don’t!)
List the five vertebrate groups.
Fish, Amphibians, Reptiles, Birds, Mammals
Explain why some organisms such as Archaeopteryx are hard to classify.
Archaeopteryx is an extinct flying creaure with feathers like bird bird teeth, claws and scales like a reptile.
Natural classification systems are based on what modern scientific techniques?
DNA analysis to show family trees
Why are Mules and Tigons are termed as hybrids rather than separate species?
A species is group of organisms which are capable of interbreeding to produce fertile offspring. Mules and Tigons are infertile.
How can you tell if 2 animals belong to the same species?
Breed them and if their offspring is fertile they are the same species. If it isn’t then it’s a hybrid.
What is the name of a human using the binomial system?
Homo sapiens (The first word is the Genus which must have a capital letter!)
Name the Swedish scientist who started the classification system.
Carl Linnaeus
Why does Euglena pose a problem for classification by this system?
Euglena has features of an animal (it can feed on sugar) and a plant (it can photosynthesise in the light).
I know this is a bird because…
It has feathers (bats also have wings and fly and are mammals!)
I know this is a mammal because…
It feeds its infants milk (most have hair but whales are the eception to this rule)
I know this is a reptile because…
It has dry scales
I know this is an amphibian because…
It has moist skin
I know this is a fish because…
It has wet scales
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How many legs does an insect have?
An insect has 6 legs
How many legs does an arachnid have?
An arachnid (spider) has 8 legs
How many legs does an crustacean have?
The crustacean have ten to fourteen legs.
How many legs does an myriapod have?
They are centipedes and millipedes and have more than 20 legs.
What do we mean by variation?
Variation is the differences between individuals within a species. This can be caused by inherited or environmental factors.
Why is an evolutionary tree useful?
They show that closely related species share a relatively recent ancestor.
Why do echidna, tenrec and hedgehogs all look similar even though they are not related?
They live in similar habitats and have adapted in similar ways to cope with the same ecological niche.
What is an ecological niche?
The conditions, habitat and food available to an organism.
Give an example of a primary producer in an ecosystem.
Producers usually are organisms which fix the sun’s energy by photosynthesis and make it available to a food chain. Plants photosynthesise but so do some bacteria and algae.
Give an example of a consumer in an ecosystem.
Anything which needs to consume food for energy e.g you!
What is biomass?
Biomass is living tissue (so when your granny tells you you have grown they could say how much biomass you have added!)
Why are pyramids of number sometimes like a Christmas tree rather than a triangle?
In certain food chains the primary producer is one large organism such as a tree.
Why are pyramids of biomass a better model of energy flow in an environment?
In the environment the energy steadily decreases as you move along the food chain. Only a pyramid of biomass can be relied upon to show this shape.
What are the problems when gathering numbers for a pyramid of biomass in a field situation?
The main problems are that 1) organisms may belong to more than one trophic level and 2) you need to kill and dry all living organisms!
How much energy is passed from one trophic level to another in a food chain?
Only 10% of the energy put into a trophic level is put into biomass and so passed onto the next level.
Where does the energy lost in a food chain go to?
The energy is lost as excretion, egestion and heat from respiration.
How many trophic levels does the longest food chain usually have? Explain why it is limited.
As the energy drops by 10% each time there can only be 5 stages at the very most as after this point there will not be any energy available for the top consumer. e.g. 100% 10% 1% 0.1% 0.01%
Explain the term trophic level.
The trophic level means the feeding level
Describe how excretory products, faeces and uneaten parts can be used as the starting point for other food chains.
In the middle of the ocean a whale’s faeces is an essential source of nitrogen for microscopic plankton. This starts another food chain in what would otherwise be an empty environment.
Explain how energy from the Sun flows through food webs.
The sun’s energy is made available to consumers by being used by photosynthesising organisms to build biomass that consumers can then digest and use as an energy source.
Name 2 elements which are recycled in nature
The 2 elements recycled in nature that you need to know about for your exam are nitrogen and carbon
What part of the rock cycle puts carbon into the atmosphere.
The eruption of volcanoes puts carbon dioxide into the atmosphere.
What part of the rock cycle takes carbon out of the atmosphere.
Sedimentation (formation of rock) from marine organisms with shells and carbon skeletons locks up carbon dioxide.
Which microbes release nitrogen?
Denitrifying bacteria release nitrogen to the atmosphere.
Which processes increase CO2 in the atmosphere?
The processes which release carbon are respiration, combustion and decay (and to a small amount volcanic eruption).
Which processes decrease CO2 in the atmosphere?
The processes which decrease carbon are photosynthesis and sedimentation.
How do animals remove waste nitrogen?
They excrete it as ammonia (e.g. fish) urea (us) or uric acid (birds and reptiles).
Which microbes lock up nitrogen?
Nitrogen fixing bacteria in the roots of legumes and nitrifying bacteria fix nitrogen.
What job do soil bacteria and fungi do within the carbon cycle?
They are decomposers which decay dead organisms and make carbon available again as carbon dioxide.
Why is the decay process important?
The decay proces is important in making elements available again to living organisms.
How do plants take up nitrogen?
Nitrogen is taken up by plant roots as nitrates which are dissolved in water.
What % of the air is nitrogen?
The amount of nitrogen in the air is 78%.
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Explain why nitrogen gas can’t be used directly by animals or plants?
Nitrogen in the air (N2) is an unreactive gas.
Explain why recycling of nutrients takes longer in waterlogged or acidic soils than it does in well drained neutral soils.
There is very little oxygen in waterlogged Soils and the pH of acid soils is very low. Both conditions make it hard for the bacteria to survive. These are needed to break down nutrients and make them available.
List 4 things plants compete for.
Plants compete for light, space, water, minerals.
List 4 things animals compete for.
Animals compete for a home, food, water, a mate.
In a predator prey graph which population numbers rise first?
The prey numbers rise first.
Explain using an example the term ‘parasite’.
Parasites are organisms that live on or in a host organism. The parasite benefits from this arrangement, but the host suffers as a result.
Explain using an example the term ‘mutualism’.
In mutualism, both species benefit from their relationship. For example, oxpecker birds eat ticks and larvae infesting the skin of buffalo and other large animals. For this reason oxpeckers are called a cleaner species.
Interspecific competition means…
Interspecific competition means a struggle for resources between members of a different species e.g. red and grey squirrels.
Intraspecific competition means…
Intraspecific competition means a struggle for resources between memebers of the same species e.g. male Red Deer compete for a mate by rutting.
By describing what the bacteria gives the plant and vice versa explain why legume roots nodules are an example of mutualism.
Peas, beans and clover have colonies of nitrogen-fixing bacteria in nodules attached to their roots. The plants gain nitrates from the bacteria, and the bacteria gain sugars from the plants.
Why are predator prey cycle graphs slightly out of sync?
Predator prey cycle graphs slightly out of sync because there is a time lag for the prey population to catch up to the prey population.
Explain how changes in the population of one organism may affect the other organisms in a food web.
Changes in the population of one organisms affect the other organisms in a food web by reducing or increasing the competition for food or the amount of predators hunting that prey organism.
Describe two adaptations which help camels survive in the desert.
Thick hide to keep out heat of the sun and large feet to stop it sinking in the sand. NB Hump does not contain water -it is full of fat!
Describe two adaptations which help polar bears survive in the arctic.
Thick hide with blubber for insulation to keep it warm in frozen conditions and large feet with hair on soles to stop it slipping and sinking in the snow.
How does the shape of a cactus increase its success in a hostile environment?
Small surface area to volume ratio means small surface in contact with hot air to prevent water loss.
How does the shape of a polar bear increase its success in a hostile environment?
Small surface area to volume ratio means small surface in contact with cold air to prevent heat loss.
Why do ears increase in size as you look at creatures from increasingly warm environments?
Large surface area in contact with the air to cool blood and maintain constant temperature.
List 5 ways in which a prey species is adapted to survive predation.
Acute senses, lives in herds and flocks so members take turns in keeping watch, synchronised breeding programme so eggs hatch together, mimicry, eyes on side of head for wide field of view, cryptic and warning colouration.
List 5 ways in which a predator is adapted to catching prey species for its survival.
Acute senses, binocular vision to judge distance and size, hunting strategy, breeding strategy, sharp teeth and claws.
How are some organisms biochemically adapted to extreme cold?
Some organisms are biochemically adapted to extreme conditions, by having a different optimum temperature for enzymes/ organisms such as lichen and arctic fish with antifreeze proteins.
How are advantageous adaptations passed on to the next generation?
They are inherited (passed on in the DNA in the nucleus of the sperm and eggs)
What does evolution mean?
Over long periods of time, groups of organisms can change and that this is called evolution.
Explain Darwin’s theory of evolution by natural selection in 4 steps
- natural variation, 2. competition for limited resources, 3.survival of the fittest, 4. inheritance of ‘successful’ adaptations.
Why is it that new species only evolve when there is geographical or reproductive isolation of populations.
The adaptations which give the organism an advantage will be diluted if new individuals join the breeding population.
Explain how Lamarck’s idea of evolution by the inheritance of acquired characteristics was different from Darwin’s theory.
Lamark believed that changes within a lifetime of an individual can be passed on to offspring because he had no idea about genes.
Which finite resources are the human population using up?
Minerals such as metals and fossil fuels such as oil, coal and gas.
Explain the causes and consequences of global warming
Cause: Greenhouse gases such as CO2/CH4 .Consequences: Increasing global temperatures and extremem weather patterns, drought, floods, sea level rise, extinctions.
Explain the causes and consequences of ozone depletion
Cause: CFC’s released from refrigerators or aerosol cans. Consequences: Hole in the ozone layer which allows dangerous levels of UV reach on Earth and increase levels of skin cancer.
Explain the causes and consequences of acid rain.
Cause: Release of acidic gases caused by burning fossil fuels. SO2 from sulphur impurities in coal, NO/NO2 from conbustion in vehicle engines. Consequences: Coniferous trees lose needles, freshwater organisms die, damage to buildings and statues made of sedimantary rocks.
What causes population growth?
An increasing population is the result of the birth rate exceeding the death rate.
Explain the term ‘carbon footprint’
The amount of greenhouse gases given off by a person and their activities in a certain period of time.
Discuss the possible consequences of exponential growth of the human population.
More plastic waste to landfill, sewage, polluting gases such as CO2 and SO2
Explain how the presence/absence of indicator species such as lichen or water lice helps to indicate the level of pollution.
Pollution can affect the number and type of organisms that can survive in a particular place. Indicator species let us know whether the air and water are clean.
Describe the advantages and disadvantages of using living and non-living methods of measuring levels of pollution.
Measuring living methods such as indicator species is a quick and cheap method which anyone can use to measure pollution. However having a computer monitored air or water analysis system gives a constant presence and so can generate an early warning if toxic material have been released. They are of course very expensive.
3 endangered animals
Panda, Lowland Gorilla, White Rhino
3 extinct animals
There are many but any dinosaur, Quagga, Dodo, Mammoth, Terror bird and Smilodon are easy to remember.
Explain why organisms become extinct or endangered due to human population increase.
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Human activity causes extinction by hunting, pollution, climate change and destruction of habitats by building or farming.
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What do we mean by a conservation programme?
A conservation programme is a planned intervention to preserve a key species
and their habitat so that the soecies doesn’t become extinct.
Describe 3 ways in which we could conserve endangered species.
Endangered species can be conserved by protecting habitats, legal protection, education programmes, captive breeding programmes, seed banks, creating artificial ecosystems.
What is a sustainable resource?
One which is preserved for the next generation.
Describe two ways in which sustainable development can help save endangered species
Quotas on fishing
re-planting of woodland
Why do zoos keep a log book to organise their breeding program?
To reduce inbreeding and maintain a large gene pool.
Why is there a critical number below which endangered animals are destined to become extinct?
Once the number of animals falls below a critical number there will not be enough animals left to prevent inbreeding.
Why has a seed bank been created within the Arctic circle?
To preserve the variety of different plants within the world and restock farms in case of a natural or man made disaster.
Why do we freeze the DNA of endangered animals?
To preserve the variety of different animals within the world and restock farmsand zoos in case of a natural or man made disaster.
Why is it a valuable resource to have whales and dolphins in the seas surrounding your country?
They attract visitors (eco tourism).
Which countries refuse to sign the international whaling treaty and keep killing whales?
Iceland, Norway and Japan.
Which aspects of whale biology are still being researched?
Migration and navigation and how they survive the high pressure at depths.
