Topic 2: Evolution Flashcards
Describe the 2 scales of evolution
Microevolution
* Allelic frequency changes over
generations
– Ultimately leads to
macroevolution
** Macroevolution**
* Phenotypic changes over
evolutionary time (millions of years)
* Evidence?
Misunderstanding : Individuals adapt to their environment
Individuals do not evolve populations evolve
* Natural selection can amplify or diminish only heritable traits
* individual’s acquired characteristics cannot be passed on to offspring
Traits that maximize individual survival will be common
Behaviors that increase fitness of related individuals may be detrimental to an individual but can be selected for if relatives carry the genes for the behavior
“Humans are the pinnacle of evolution”
Evolution hasn’t directed
the production of species
toward some end point
The theory of evolution indicates that “humans evolved
from closely related primates.
Humans and chimpanzees share a common ancestor
The theory of evolution explains the initiation of life on earth
The theory of evolution focuses on the
mechanism of natural selection after the
first organism appear
Complex organisms couldn’t have arisen by
chance; they’re too complex”
Environmental changes that lead to survival of one type of organism or another at that point in time can happen by “chance”. E.g,, floods, fires
- Species alive today, result from an evolutionary history of adaptation to environment
There are gaps in the fossil record /missing
links
Not all fossils are preserved
* Many species leave no fossils due to environmental
conditions for forming good fossils being uncommon
ex- plants don’t have a skeleton therefore no fossils and we don’t know much abt them
Fitness
match to enviroment
allele
variation of a gene
code for the same trait but one could be homozygous and one could be hetreozygous
Outline the 4 conditions that made the origin of life possible
- abiotic synthesis of small organic molecules
- joining of the small molecules into macromolecules
- packaging of molecules into protocells
- origin of self replicating molecules
What did Darwin note?
current species are descendants of ancestral species
How can evolution be defined by Darwin?
descent with modification
the idea that species change over time, give rise to new species, and share a common ancestor.
What did Lamrack propose?
something that was acquired during an organisms life was passed on
NOT TRUE- acquired traits arent’s genetic and can’t be passed on
Describe Darwins main observations and inferences
variability and heritability of character traits
overproduction of offpring
- competition between offspring
- favourable characters amass over time
artificial selection
humans have modified other species by selecting and breeding individuals with desired traits
humans choose which organisms breed and which do not
humans are the selective pressure
more goal oriented
faster
TRAITS MUST BE VARIABLE AND HERITABLE
relative fitness
contribution an individual makes to the gene pool of the next gen relative to other individual
Which traits lead to relative fitness?
- not having a genetic disease
- not getting eaten
- survivng enviromental condition
- accumulating nutrients
- attracting mates
- ability to produce gametes
Summarize microevoltion in the peppered moth
pre- light selected for
post- black selected for
present- white
Homologous structures
similar physical features in organisms that share a common ancestor, but the features serve completely different functions
ex-forelimbs of mammals even though they all have different functions are structurally similar
analogous structures
similar in function but not from common ancestor
- cant expain evolutionary relationships
vestegial homolgies
doesn’t serve a purpose
compare divergent and convergent evolution
Convergent evolution is when two species with different ancestral origins develop similar characteristics, while divergent evolution refers to when two species diverge from a common ancestor and develop different characteristics.
Most atmospheric O2 is…
of biological origin
