science vocab

Vocabulary Word	Definition in Plain English	Whale Example to Use
Common Ancestor	An older species that two or more modern lines branched out from.	The ancient land mammal that both modern hippos and modern whales evolved from.
Homology	Traits that share the same internal structure because they came from a common ancestor (even if functions differ).	The arm bones of a human matching the internal flipper bones of Pakicetus and modern whales.
Convergent Evolution	Unrelated species evolving similar traits because they live in similar environments with similar pressures.	Whales and sharks both evolving smooth, streamlined bodies to cut through water quickly.
Analogous Structure	The opposite of homology. Traits with different internal builds that do the same job due to convergent evolution.	A whale's horizontal tail fluke vs. a shark's vertical tail fin.
Vestigial Structure	A physical trait that has lost its original function due to evolution but remains as a skeletal "leftover."	The tiny, non-functional hip bones floating inside Dorudon and modern baleen whales.
Cladogram	A branching tree diagram used to show evolutionary relationships based on shared traits.	The diagram tracking whales from land (Pakicetus) to sea (Balaena).
Uniformitarianism	The scientific law stating that natural processes observed today operated the same way in the past.	Knowing Ambulocetus needed to breathe air because it is classified as a mammal, and all modern mammals breathe air.