LO15 Flashcards
definition: the accumulation of genetic changes within populations over time
evolution
definition: a group of individuals of the same species living in the same geographic region at the same time
population
What is the unifying concept in biology?
evolution
Explains both similarities and differences among living organisms
evolution
provides a scientifically testable mechanisms for how life could have originated from a common ancestor
evolution
Do individual evolve?
no populations do
definition: involves minor genetic changes within a population or species over a few generations
microevolution
The emergence of a new viral strain is an example of what kind of evolution?
microevolution
definition: a group of organisms with similar genetics, structure, cunction, and behavior that can interbreed
species
definition: involves major genetic changes usually over long periods of time that form new species
macroevolution
Microevolutionary process explain what?
How macroevolution occurs
What philospher arranged living organisms in a scale of nature?
Aristotle
How was the scale of nature organized?
from more simple to more complex
What ways did Aristotle think living organisms were changing towards?
perfection
What did Leonardo da Vinci recognize?
That fossils were the remains of once living organisms
definitions: remains of once living organisms
fossils
Who was Lamarck?
a french naturalist who said that organisms changed over time by natural phenomena
What was Lamarck hypothesis?
The inheritance of acquired characteristics
To Lamarck what would a changing environment do to organisms?
It would change their behavior to use some body parts more or less depending on what is needed
To Lamark what would happen to any changes acquired by an organism to the offscpring?
They could be passed on
Who was Darwin?
An english naturalist who developed the theory of evolution by natural selection
Darwin’s theory explained what?
that better adapted organisms are more likely to survive and reproduce
definition: a genetic trait that improves the chances of survival and reproduction in a given environment
adaptation
Where did most of Darwin’s ideas come from?
His observations during the voyage of the HMS Beagle
Adaptation increase the likelihood that organisms will _______ and ______ to a greater extent?
survive; reproduce
Who was Darwin influenced by?
Charles Lyell and Thomas Malthus
What did Lyell discover?
That the earth’s physical features were the result of geological process that occur over long periods of time.
What did Darwin realize from Lyell?
That the earth was old enough for species to have had time to evolve
What did Malthus suggest?
That the human population growth is not always desirable?
What did Darwin realized from Malthus?
That there is a struggle for existence in nature; survival of fittest
What does the conflict between population growth and limited resources do?
Keep population size in check
What are the four premises of evolution by natural selection?
- individuals are genetically variable
- In every generation more offspring are produced than can survive
- survival is limited by resources
- individuals with inherited variations that increase their survival and reproduction are favored
adaptive traits do what to frequency with each generation?
increase in frequency
Over long periods of time, enough changes would do what?
produce new species
Requires geographic separation
speciation
definition: a unified theory of evolution combining Darwin’s theory of natural selection with Mendelian inheritance principles
modern synthesis
What did the modern synthesis show?
It showed how mutations provide the genetic variations that natural selection acts on
Who was Alfred Russel Wallace?
a british naturalist that made a hypothesis similar to darwins
What provides a direct evidence of evolution?
a fossil
definition: remains or traces of organisms left in sedimentary rock
fossils
how does sedimentary rock form?
it forms in layers over time
What happens during fossilization?
the details of an organism are preserved as minerals replace the tissues of the organism
do most organisms become fossilized?
no they do not
Organisms living in which type of environment are more likely to fossilize?
aquatic environments
Organism with which types of bodies or body structures are more likely to fossilize?
hard body parts (vertebrates; exoskeletons)
What is in the oldest deepest part of sedimentary rock layers contain?
ancient unicellular or simple multicellular organism
What is in the shallower layers of sedimentary rock?
contains more recent organisms and more complex multicellular organisms
definition: shows the gradual evolution of a group of organisms via intermediates
transitional fossil
definition: the study of the geographic distribution of living and extinct organisms
biogeography
definition: movements of continents due to plate tectonics
continenetal drift
what played a major role in biogeography and evolution?
continental drift
related organisms share what kind of features that they inherited from their common ancestor?
homologous features
definition: features that have a common underlying structure
homologous features
What is the reason that there is a similarity in bone, muscle and nerve structure among different vertebrate forelimbs.
common ancestry
comparative anatomy reveals what?
homoplasy
comparative anatomy reveals what?
homology
Organisms can share superficially similar features that evolved how?
independently not from a common ancestor
definition: when similar environmental pressures result in similar adaptation among oganisms
homoplasy
What does homoplasy demonstrates?
the power of natural selection through convergent evolution
definition: the independent evolution of functionally similar structures in organisms that were not inherited from the common ancestorr of those organisms
convergent evolution
comparative anatomy reveals what?
vestigal structures
How do structures become vestigial?
They adapt to different modes of life or a changing environment
definition: a nonfunctional or degenerate remnant of a structure that was once functional in an ancestor
vestigial structure
What are examples of vestigial structures in humans?
coccyx, wisdom teeth, ear muscles
What are examples of vestigial structures in whales and pythons?
hind limbs
What are examples of vestigial structures in cave organisms?
eyes and pigment
definitions: nonfunctional genes that have lost their protein-coding ability due to mutation and are no longer expressed
pseudogenes
Examples of a pseudogenes is what?
Human olfactory senses
Vertebrates share a similar pattern of development due to what?
A common ancestry
All vertebrates embryos have what?
segmented muscles, throat pouches, a tubular heart, and an aortic arch
Aquatic vertebrates do what to the features they have in their embryos?
they keep and retain them as adults
Terrestrial vertebrates do what to the features they have in their embryos?
They do not need them
