Comparative Anatomy
The three kinds of comparative anatomy used for evolution evidence
What is analogous structures, homoglous structures, and vestigial organs
These preserved remains or traces of ancient organisms are typically found embedded within layers of sedimentary rock
What are fossils?
This term describes an organism in its earliest stage of development, before it is born or hatches from an egg
What is an embryo?
If a scientist finds that a dog and a wolf have nearly identical protein chains in their blood, it proves they have a very high degree of this genetic relationship.
On a cladogram, this specific point where two lines branch apart represents the moment an ancestral species split into new lineages.
What is a node?
These body parts have similar functions but different underlying structures, proving that species evolved independently to adapt to similar environments.
What are analogous structures?
This type of fossil, such as Archaeopteryx, shows structural links between an ancestral group and its modern descendants
What is a transitional fossil?
In the early stages of development, a human embryo looks incredibly similar to a fish embryo, which points to a shared evolutionary history called this.
What is common ancestry?
If two species split from a common ancestor very recently, you would expect the number of differences in their DNA sequences to be this.
What is low? or
What is small?
These physical traits or genetic characteristics are shown in future organisms but not past organims.
What are derived characters?
These anatomical remnants like the human appendix or pelvic bones in whales serve no modern function but reveal ancestry.
What are vestigial structures?
Because newer sediment piles on top of old layers, a fossil found deep underground is generally considered this compared to a fossil found near the surface.
What is older?
Even though adult humans do not have tails, human embryos possess one during early development, which later shrinks into this vestigial bone
What is the tailbone?
Scientists can build an evolutionary tree just by counting the number of differences in this specific type of cellular code
What is a genetic, DNA, or amino acid sequence?
The fact that all living things use this identical molecule to store genetic code is major evidence that all life shares a common ancestor.
What is DNA?
The evolutinary term for a human arm, a bat wing, and a whale flipper with different functions but underlying identical bone arrangements.
What are homologous structures?
These hardened remains or impressions—like footprints, bones, and teeth—provide physical proof of animals that lived millions of years ago
What are fossils?
All vertebrate embryos including humans, chicks, and fish develop these matching slits near their throat, though they later turn into gills for fish and jaw bones for humans
What are gill slits?
To determine how closely related two species are, scientists compare the sequence of these building blocks that make up their proteins.
When building a cladogram, this is the name given to a closely related group outside the main study group, used to determine which traits are ancestral versus derived
What is an outgroup?
Two species share a complex bone structure but use it for completely different tasks, it is evidence that they share one of these
What is a common ancestor?
This term describes the complete collection of all fossils ever discovered on Earth, which scientists use like a giant puzzle to map out the history of life.
What is the fossil record?
Two animal species might look identical as early embryos but look completely different as adults because these biological blueprints code for unique traits that only appear later in development.
What are genes? or What is DNA?
Even if two animals have completely different body shapes, their cells still use this specific, universal nucleic acid to carry genetic messages from the nucleus to the ribosome
What is mRNA? or RNA?
If a derived trait like "has fur" is written on a cladogram branch, it means this many of the animal species listed above that mark will possess fur
What is all of them?