Week 8- Evidences of Evolution Flashcards
Two types of Evolution based on scale
Macroevolution and Microevolution
These are similar features that have evolved
independently in different organisms because the
organisms lived in similar environments or
experienced similar selective pressures/natural
selection.
Vestigial Features
Refers to small-scale changes that
affect just one or a few genes and happen in populations
over shorter timescales.
Microevolution
Microevolution and macroevolution are the same
process, occurring on different timescales.
_______________ processes occurring over
thousands or millions of years can add up to large-
scale changes that define new species or groups,
which is the basis for _______________
Microevolutionary/Microevolution, Macroevolution
Refers to large-scale changes that
occur over extended time periods, such as the formation of
new species and groups.
Macroevolution
In molecular Biology, give the 4 things that all living organisms share at the most basic level.
-The same genetic material (DNA)
-The same, or highly similar, genetic codes
-The same basic process of gene expression (transcription
and translation)
-The same molecular building blocks, such as amino acids
The presence of structures in organisms that share
the basic trait. A similarity of said trait results from
their origin in the trait of a common ancestor.
Homologous Features
Types of Features/Traits
Homologous Features
- Vestigial Features
Analogous Features
The process which the organisms undergo to acquire Vestigial Features is called…
Convergent evolution
What did Darwin though of evolution?
“Descent with modification”
Sometimes, organisms have structures that are homologous to
important structures in other organisms but that have lost their
major ancestral function. What kind of feature is this?
Vestigial Features
He proposed that the evolutionary history of life forms a branching tree with many levels, in which all species can be traced back to an ancient common ancestor.
Charles Darwin
Physical traits/features shared due to evolutionary
history (a common ancestor) are said to be
__________________.
Homologous
Some homologous structures can be seen only
in _____________. For instance, all vertebrate embryos (including humans) have ________ and a ______ during early development.
Embryos, Gill Slits and Tail
reflect that the developmental programs of vertebrates are variations on a similar plan that existed in their last common ancestor.
Homologous Embryonic Structure
Example of Vestigial Features in Humans
Wisdom Tooth
Appendix
Male Nipples
Third Eyelid
Tonsils
Palmaris Longus Muscle
Although they’re great for establishing the common origins of life, features like having DNA or carrying out transcription and translation are not so useful for figuring out how related particular organisms are.
Molecular Biology
Biologists often compare the sequences of related genes found in different species (often called homologous or orthologous genes) to figure out how those species are evolutionarily related to one another.
Homologous Genes
The basic idea behind Homologous Gene Approach is that two species have the “_________” gene because they inherited it from a common ancestor.
Same
For instance, humans, cows, chickens, and chimpanzees all have a gene that encodes the hormone ________, because this gene was already present in their last common ancestor.
Insulin
In general, the more ____________ in homologous genes (or amino acid differences in the proteins they encode) between two species, the more ________ the species are related.
DNA Differences, Distant
For instance, human and chimpanzee insulin proteins are much more similar (about __________identical) than human and chicken insulin proteins (about _____________identical), reflecting that humans and chimpanzees are more closely related than humans and chickens.
98%, 64%
The geographic distribution of organisms on Earth follows patterns that are best explained by evolution, in combination with the movement of tectonic plates over geological time.
Biogeography
For instance, most of the mammal species in Australia are ____________, while most mammal species elsewhere in the world are ___________.
Marsupials, Placentals
Australia’s marsupial species are very diverse and fill a wide range of ecological roles.
Biogeography
Because Australia was ____________ for millions of years, these species were able to evolve without ____________ from (______________) mammal species elsewhere in the world.
Isolated by water, Competition/Exchange with
show a progression of evolution through their preserved remains of previously living organisms or their traces, dating from the distant past.
Fossils
Scientists determine the ______________ and categorize them all over the world to determine when the organisms lived relative to each other.
Age of Fossils
The resulting__________ tells the story of the past, and shows the evolution of form over millions of years.
Fossil Record
Example is the lineage of the____________, which shows the reduction of ___________________, may reflect adaptation to changes in the environment.
Modern Horse, toed feet to hooves
Equus
Modern Horse
Some evolutions are happening and is being observed today. Important modern-day examples of evolution include the emergence of drug-resistant bacteria and pesticide-resistant insects
Direct Observation
history of the evolution of a species or group, especially in reference to lines of descent and relationships among broad groups of organisms
Phylogeny