9.Evolution Flashcards
what is a selective agent/pressure
a factor in an organisms environment that removes unsuited individuals from a population
what is biological fitness
biological fitness is the ability to survive, reproduce and pass on alleles to the next generation
VA scaffold
There is a variation in the phenotypes in the ________ population due to random mutations as __________
ST scaffold
All organisms face a daily struggle to survive and reproduce, The ___________ with _________ struggle because __________ (selection pressures)
SE scaffold
The ________ have a selective advantage as _______________________
IN scaffold
The organisms that have a selective advantage (_____________), survive, reproduce and their offspring inherit the alleles for the trait of ______________
E scaffold
Evolution occurs by natural selection and there is a change in allele frequency over time and the _________ population becomes better suited to its environment
what order do humans belong to
primates
identify shared characteristics of primates
1.Prehensile or grasping hand
2.Opposable thumbs(s)
3.Flat finger nails instead of claws and sensitive tips of digits
4.large, forward facing eyes
5.large brain volume in comparison to body size
what is meat by bipedalism
walking on two legs rather than four
advantages of bipedalism
-more energy efficient than walking on four legs
-bipeds can see further than quadrupeds of similar size
-able to hold objects while walking
disadvantages of bipedalism
-slower top running speed
-greater visibility to predators
-greater pressure on spine and back muscles
identify hominid characteristics
-reduced arm-to-leg ratio
-pelvis more bowl-like
-loss of opposable big toe/thumb
-larger heel bone (calcaneus)
-foramen magnum moved under base of skull
-increased brain to body ratio
describe arm to leg ratio in hominids
-humans have shorter arms in comparison to leg length than the primates and hominids
-being no longer arboreal, long arms are not required
-shortening arms makes walking more stable and saves energy
-makes precision tasks easier
describe pelvis in hominids
-human pelvis has evolved to become more bowl like than those of quadrupedal primates
-this spreads mass of the upper body which is now supported by two legs, resulting in reduced pressure on pelvis and increased stability
describe opposable thumb/toe in hominids
-an opposable thumb on the foot is selected against if bipedal
-a big toe aligned with the rest of the foot enables toes to become flatter against ground, improving stability when walking
describe heel bone in hominids
-calcaneus has enlarged to support the effect of increased body weight on the feet
-an arched foot is also a feature of more recent hominids as another pressure-reducing measure
describe foramen magnum in hominids
-the is the hole base of the skull through which the spinal chord passes
-being bipedal, the head is better balanced if the foramen magnum is more central to the base of the skull
describe brain size in hominids
-sperm whale has largest brain in animal kingdom
-hominids have relatively large brains for our body size
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what are genetically modified organisms +eg
these are organisms whose genome has been altered in some way
eg Flavr Savr tomatoes, where genes responsible for ripening have been removed
what are transgenic organisms +eg
they are genetically modified organisms where genes from a different species are added to their genome
-known as a transgene
eg.Bt cotton (transgenic insecticide genes from bacteria added to cotton)
Biological implications of genetically modified organisms
-GMOS may have effects on the environment, ecosystem and other living things
-GM crops may cross pollinate with a related, wild species
T of F all TGOS are GMOS
true- all TGO’s are GMO’s
Social implications of genetically modified organisms
ethical implications of genetically modified organisms
-may be morally incorrect to genetically modify and organism
-questions on who owns a gene, or the genome of an altered crop
