Page 2 Flashcards
(17 cards)
What problems are there with the basing the idea of a species on their reproduction?
Some different species can reproduce to make hybrids.
What is the general definition of a species?
reproduce with each other to produce fertile offspring.
What problems are there with the basing the idea of a species on their anatomy?
Dog breeds all look very different but are in fact the same species. Also some species have males and females that look different.
What is the binomial classification system?
Using 2 Latin names - the Genus and the species.
How can the binomial classification system help to target conservation efforts?
It allows accurate identification of individual species wherever they are. For example: a robin in the UK isn’t the same as a robin in America so by using the binomial name “Turdus Migratorius” (american robin) and “Erithacus Rubecula” (UK robin) there is no confusion.
How is classification complicated by ring species?
Neighbouring populations of species (e.g. gulls) may have slightly different characteristics but can still interbreed as part of a chain (next to each other) but the two ends of the chain can’t interbreed.
How are polar bears adapted to their Arctic habitat?
A white appearance, as camouflage from prey on snow and ice
thick layers of fat and fur for insulation from the cold
A small surface area to volume ratio, to minimise heat loss
A greasy coat, which sheds water after swimming.
In natural selection, what does variation refer to?
Most populations of organisms contain individuals which vary slightly from one to another.
In natural selection, what does overproduction refer to?
Most organisms produce more young than will survive to adulthood.
In natural section, what does the struggle for existence refer to?
Because populations do not generally increase rapidly in size there must therefore be considerable competition for survival between the organisms.
In natural selection, what does survival of the fittest refer to?
Those with advantageous characteristics (the more likely to get mates/food/escaping predictors) are the more likely to survive the struggle
In natural selection, how are advantageous characteristics inherited?
Better adapted organisms are more likely to reproduce successfully passing on the advantageous genes to their offspring.
In natural selection, what happens gradually over time?
The proportion of individuals with the advantageous characteristics in the population increases compared with the proportion of individuals with poorly adapted characteristics, which may eventually be lost.
Give 2 examples of continuous variation.
Height, weight, foot length, (there is a range from high to low in population.
Give 2 examples of discontinuous variation.
gender
blood group (A, B, AB or O)
Eye colour
(There are not in between values)
What are the 2 causes of variation?
Genetic or environmental.
What does genetic variation mean?
Different characteristics as a result of mutation (changes in the DNA) or sexual reproduction (Shuffling up of chromosomes)
e.g. eye colour.
