Unit 2 - biodiversity and evolution

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Define species?
A group of individual organisms very similar in appearance, autonomy, physiology, biochemistry and genetics, whose members are able to interbreed to produce fertile offspring.
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Define habitat?
Is the place where an organism lives.
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Define biodiversity?
Is the variety of life, the range of living organisms to be found.
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In 2007, how many known species were there in the world?
1 008 965
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In which classification group is there most species?
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Define random sampling?
Studying a small part of the habitat and assuming it contains a representative set of species that can be applied to the whole habitat.
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How do you sample animals?
You have to catch them in a trap because they move around. Then take your sample from the species found in the trap.
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What are the five ways of catching animals?
Sweep netting, collecting from trees, a pitfall funnel, a Tullgren funnel and a light trap.
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How does a Tullgren funnel work?
You place leaf litter in a funnel, the light above them dries the litter out and drives the animals downwards. They fall through a mesh and are collected in a jar below.
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How does a light trap work?
It consist of an ultraviolet light with a collecting vessel containing alcohol below. The insects are attracted to the light and eventually fall into the alcohol below.
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What is species richness?
The number of species in a habitat.
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What is species evenness?
The number of each of individuals in each species.
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What is Simpson's Diversity Index?
A formula used to measure the diversity of a habitat. It takes into account the species richness and species evenness.
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What is the formula for Simpson's Diversity Index?
D= 1- [∑(n/N)2]
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If an area has a high Simpson's Diversity Index value, what does it mean?
It is more biodiverse.
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If an area has a low Simpson's Diversity Index value, what does it mean?
It is less biodiverse.
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Define classification?
The process of sorting living things into groups. Natural classification does this by grouping things according to how closely related they are. Natural classification reflects evolutionary relationships.
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Define phylogeny?
The study of the evolutionary relationships between organisms.
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Define taxonomy?
The study of principles of classification.
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What is the relationship between classification and phylogeny?
Phylogeny refers to the evolutionary relationship of organisms; it's a family tree for all life on Earth. These days, classification seeks to work by grouping organisms into units based on common ancestors. That approach is phylogenetic.
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What are the five kingdoms?
Animals, plants, fungi, protoctists and prokaryotes.
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Define animals?
Heterotrophic multicellular eukaryotes.
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Features of animals?
They are eukaryotes, multicellular, heterotrophic nutrition, have fertilised eggs and are able to move around.
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Define plants?
Multicellular organisms that gain their nutrition from photosynthesis.
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Features of plants?
They are eukaryotes, multicellular, have cell walls made of cellulose, produce multicellular embryos, have autotrophic nutrition.
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Define fungi?
Organisms that are mostly saprotrophic. They consist of mycelium with walls made from chitin.
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Features of fungi?
They are eukaryotes, have mycelium, have walls made of chitin, have cytoplasm that is multinucleate, mostly free living and saprotrophic.
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Define protoctists?
Include all the organisms that don't fit into the other four kingdoms. Many are single celled, but some are multicellular.
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Features of protoctists?
They are eukaryotes, mostly single celled, wide variety of forms, show animal and plant like features, free living, and have autotrophic or heterotrophic nutrition.
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Define prokaryote?
Have no nucleus.
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Features of prokaryotes?
They have no nucleus, have loop of DNA, no membrane bound organelles, smaller ribosomes, carry out respiration on membrane systems, have smaller cells and may be free living.
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Why do we classify living things?
For our convenience, to make the study of them more manageable, to make it easier to identify them and to help us see the relationships between them.
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List the order of the eight taxa?
Domain, kingdom, phylum, class, order, family, genus and species.
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Define The binomial system?
Uses two names to identify each species: the genus name and the species name.
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Why do we use the binomial system?
Because using a common name does not work well, they may have different names in different countries, translations may give different meanings and the same common name may be used for different species in different parts of the world.
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Define dichotomous key?
Uses a series of questions with two alternative answers to help you identify a specimen.
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Which five features should you look for when classifying?
Anatomy, physiology, biochemistry, genetics and embryological.
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What did Aristotle look for when classifying?
Live and move in water, live and move on land and move through air.
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What are two more recent ways of classifying?
Biochemistry looks at cytochrome C and DNA.
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Define variation?
the presence of variety - of differences between individuals.
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Define genetic variation?
Is caused by differences between the genes and the combinations of genes or alleles.
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Define continuous variation?
Is the variation in which there is a full range of intermediate phenotypes between two extremes.
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Examples of continuous variation?
Hight in humans, length of leaves on an oak tree and length of stalk on a toadstool.
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Define discontinuous?
Is variation in which there are discrete groups of phenotypes with no or very few individuals in between.
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Examples of discontinuous variation?
Sex (male or female), some bacteria have flagella and human blood group (A, B, AB or O).
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What two factors cause variation?
Inherited or genetic factors, or environmental factors.
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Define adaptation?
A feature that enhances survival and long term reproductive success.
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Define xerophytic?
Plants that are adapted to living in very dry conditions.
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What are behavioural adaptations?
An aspect of behaviour of an organism hat helps it to survive the conditions it lives in.
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What are physiological/biochemical adaptions?
One that ensures the correct functioning of cell processes.
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What are anatomical adaptions?
Any structural elements that enhance the survival of the organism.
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Examples of behavioural adaptations in xerophytic plants?
They close their stomata when little water is available, only open their stomata at night, roll or fold their leaves when little water is present and some open their stomata when little water is present so they wilt and expose less SA to the sun.
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Examples of physiological/biochemical adaptations in xerophytic plants?
The saguaro cactus has a stem with a folded structure. When it is dry the folds tighten into ridges and become more pronounced. When it is wet, water is taken up and can be stored in the cels of the stem for years. The stems folds expand.
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Examples of anatomical adaptations in xerophytic plants?
The roots me be shallow but cover a wide area, the roots may be very long, the stem or leaves may be fleshy, the leaves may have a reduced size, the leaves may be waxy and the leaves may curl, fold, have hairs or stoma in deep pits.
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Define natural selection?
The selection by the environment of particular individuals that show certain variations. These individuals will survive to reproduce and pass on their variations to the next generation.
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Define speciation?
The formation of a new species.
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What are the four observations listed by Darwin in his theory of natural selection?
Offspring generally appear similar to their parents, no two individuals are the identical, organisms have the ability to produce large numbers of offspring and populations in nature tend to remain fairly stable in size.
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What evidence is there for the theory of evolution?
Darwin found a group of fossilised organisms called Brachiopods. The fossils were found in rocks that had formed over a long period of time, and Darwin found that the fossils had also changed over time. Rocks from different times contained different Brach
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More recent evidence for the theory of evolution?
Biological molecules. They are found throughout the world, but very similar, suggesting they share an original ancestor. In species only closely separated, the biological molecules are very similar, less then in species long separated.
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What factors cause extinction?
Genes of a species, harmful human activity, hybridisation, habitat degeneration, new organisms causing competition and natural phenomena.
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Economical reasons to conserve species?
Soil becomes infertile, resulting in food shortages. Evolution is an answer to many problems.
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Ecological reasons to conserve species?
Keystone species are important in regulating ecosystems.
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Ethical reasons to conserve species?
All living organisms have a right to survive and live in the way they have become adapted.
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Aesthetic reasons to conserve species?
We experience a feeling of joy and wellbeing when observing the many variations of nature. Studies have shown patient recover more rapidly when exposed to a pleasing natural conditions.
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Effect of climate change on agriculture?
Higher CO2 levels altering photosynthesis, higher temp increasing growth rates, longer growing seasons, greater precipitation, change in distribution of precipitation and loss of land due to rising sea levels.
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Effect of climate change on diseases?
Crops growing in new areas will encounter new diseases, more diseases will be able to survive winter causing greater infestations earlier in year. Human diseases will migrate, Anopheles mosquito will migrate carrying malaria.
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Define conservation in situ?
Conserving a species in its normal environment.
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Advantages of conservation in situ?
Organisms still have all resources they're accustomed to, continue to evolve in natural habitat, species have more space and it is cheaper.
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Disadvantages of conservation ex situ?
Difficult to control illegal exploitation like poaching and difficult to control alien species.
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Define conservation ex situ?
Conserving an endangered species by activities that make place outside the natural environment.
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Advantages of conservation ex situ?
Works well for species easily bred in captivity, can save species that would be extinct in the wild.
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Disadvantages of conservation ex situ?
Do not evolve with their environment, have a small gene pool to breed from, able to conserve species but often becomes extinct in wild and can cause distress to animals.
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Outline botanical gardens?
Show same problems as captive breeding, range of species limited and distribution in botanical gardens reflects colonies.
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Outline seed banks?
Can be maintained for decade if controlled, 5% humidity and -20˙C, not all species suited to treatment, seeds need to be regular germinated, duplicate stocks can be made and seed banks do not evolve with environment.
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List the two organisations protecting species conservation?
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What has CITES done?
Set up in 1988 to control sustainable exploitation of species. Categorises species into 3 appendixes, depending on status.
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Card 2


Define habitat?


Is the place where an organism lives.

Card 3


Define biodiversity?


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Card 4


In 2007, how many known species were there in the world?


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Card 5


In which classification group is there most species?


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