*Unit 7 Part 3: Evidence of Evolution Flashcards
Evolution
Fossil
Evidence of an organism that lived long ago
Scientists have used the _____ record to construct a history of life on Earth.
fossil
Scientists have found _____ that have traits of two different classes of organisms.
“missing links”
Fossils are usually found in _____ rocks.
sedimentary
Hard body parts become fossilized when…
minerals replace tissue over time.
Law of superposition
New layers of rock are deposited on top of older ones
Relative dating
~Law of superposition
~Older fossils are found deeper than newer fossils
Radioactive dating
~AKA absolute dating
~Gives actual age of fossils
~Calculated age by examining the amount of radioactive element remains in a fossil
~Uses half-life
Half-life
How long it takes for half the atoms of a radioactive element in a sample to decay
The _____ is known for many elements, so it can be used to calculate the age of a fossil.
half-life
Homologous structures
~Features with similar underlying structures inherited from a common ancestor
~May have adapted for different functions over time
The forearms of a human, bat wing, whale flipper, and caw paw all have similar underlying structures that have evolved over time. What is this an example of?
Homologous structures
Analogous structures
~Do not show common ancestry
~Structures that independently evolved to perform the same function
~Have different underlying structures
An insect wing, bat wing, and bird wing have no similar underlying structures, but they perform the same function. What is this an example of?
Analogous structures
Vestiges means…
left over.
Vestigial structures
~Structures that appear to have no function
~Were once useful to an ancestor
List examples of vestigial structure in humans.
~Appendix
~Tail bone
~Goose bumps
~Body hair
More related species have similar _____ development.
embryo
Human embryos contain _____ and _____- features that disappear during development.
gill-arches; tail
All living things have DNA with the same _____ and many shared _____.
4 bases; proteins
The more similar the _____, the closer the ancestry of the organisms.
genes
Real-Time Observations
Instances of evolution by natural selection occuring right before our eyes
Rock pocket mice, peppered moths, antibiotic, and pesticide resistance are all instances of natural selection occuring right before our eyes. This is otherwise known as…
real-time observations.
Are humans still evolving?
Yes
Is the following statement true or false?
Humans evolve much differently than other organisms.
True
Many human genes are _____.
polygenic
Many human adaptations are through…
technology and migration.
As dairy farming increased, the _____ gene remained turned on in more humans.
lactase
The antibiotic resistance in bacteria happens quickly because…
bacteria reproduce quickly.
How did the antibiotic resistance occur in bacteria?
- A few bacteria in a population happen to carry a gene that allows them to be resistance to an antibiotic
- After being treated with the antibiotic, most normal bacteria dies
- The resistent bacteria multiply
- Eventually, the entire infection evolves into a resistant stain which can be passed to others
