3B3 Evidence of Evolution and Origins of Life Flashcards
Describe the fossil record, molecular evidence, and geological location as evidence of evolution. Understand cladograms and phylogenetic trees. Describe the theory of life's origin on Earth and methods used to replicate those conditions.
What is the field of paleontology?
The study of prehistoric life, including fossils, footprints, and past climatic events.
How do fossils contribute to understanding evolution?
By forming a biological timeline that shows historical changes in organisms.
What is radiometric dating used for in paleontology?
To determine the age of rocks and fossils.
What is biogeography?
The study of how species are distributed across Earth.
What did Charles Darwin observe about animals on the Galapagos Islands?
They were very similar to animals on the South American mainland but dissimilar to animals on other islands with similar environments.
What evidence supports the evolution of whales and dolphins from land animals?
The body structure of whales and dolphins, including flippers and small internal back limbs.
What is homology in comparative anatomy?
Similar characteristics in organisms from a common ancestor.
What is studied in embryology to compare evolutionary relationships?
Embryos, looking for shared structures during development.
Why is molecular biology used to study the evolution of organisms that are very distantly related?
Because the relationship between such organisms can be difficult to link with anatomy.
Molecular biology examines DNA of organisms to see if there are any similarities that could point to those organisms being related.
What does the degree of difference in DNA between organisms tell us?
How distant the ancestor is.
What is the definition of endosymbiosis?
The symbiosis where one species lives inside another species.
What is the definition of endosymbiont?
The species that lives inside another species.
Example: Nitrogen fixing bacteria in the roots of plants
What is the definition of host in endosymbiosis?
The species containing the endosymbiont.
What is the Endosymbiotic Theory?
The theory that mitochondria and chloroplasts were once free-living prokaryotic cells that formed an endosymbiotic relationship with a proto-eukaryotic or eukaryotic host cell.
What evidence supports the endosymbiotic theory?
Similarities in DNA, enzymes, and membrane structures between prokaryotes and mitochondria and plastids.
What did the aerobic endosymbionts evolve into?
Present-day mitochondria.
What did the photosynthetic endosymbionts evolve into?
- Present-day chloroplasts
- Other plastids
How do mitochondria and chloroplasts replicate?
Via a process called binary fission.
Similar to some bacterial cells.
What is a Molecular clock?
A clock that measures the constant rate of change in an organism’s genome (DNA or protein sequences of a specific gene) over time, representing species divergence and evolution.
When was the molecular clock discovered?
1962
Discovered by chemist Linus Pauling and biologist Emile Zuckerkandl during the exploration of protein sequences.
How can one calculate the age of species divergence using the molecular clock?
By dividing the number of mutations between two related species by the mutation rate to determine the timeframe of divergence.
What issue arises with the accuracy of dating back timescales using the Molecular Clock?
The presumption that genes mutate at a relatively constant rate for different lineages, which may not always be the case.
What is a cladogram?
It displays the relationships between organisms based on their characteristics or ancestors.
The Greek root ‘clados’ means branch, and ‘gram’ means written.
How are organisms sorted in a cladogram?
- Direction of their pubis bone.
- Number of legs they walk on.
- Presence of armor.
