Tree of Life
This part of a phylogenetic tree represents the most recent common ancestor of all organisms shown.
(What is the Root?)
These structures have the same internal anatomy (like bones) because they were inherited from a common ancestor.
(What are Homologous Structures?)
These are remnants of organs or structures that had a function in an ancestor but are now useless, like a whale's pelvic bone.
(What are Vestigial Structures?)
This is the general term for the process by which one species splits into two or more distinct species.
(What is Speciation?)
These are reproductive barriers that happen before an egg is fertilized.
(What are Pre-zygotic Barriers?)
This specific point on a tree represents where a single lineage splits into two, signifying a common ancestor.
(What is a Node?)
This type of evolution leads to homologous structures as related species adapt to different environments.
(What is Divergent Evolution?)
This is the most precise form of evidence for evolution, comparing A, T, C, and G sequences.
(What is DNA Evidence/Molecular Biology?)
This type of speciation occurs when a physical barrier, like a mountain range, divides a population.
(What is Allopatric Speciation?)
If two species of frogs don't mate because one breeds in March and the other in June, it is this type of isolation.
(What is Temporal Isolation?)
These are two groups of organisms that are each other's closest relatives because they share a common ancestor not shared by any other group.
(What are Sister Taxa?)
This type of evolution occurs when unrelated species evolve similar traits because they live in similar environments.
(What is Convergent Evolution?)
This "chronological record" shows transitional forms that bridge the gap between ancient and modern species.
(What is Fossil Evidence?)
This type of speciation occurs without a physical barrier
(What is Sympatric Speciation?)
A mule (the sterile offspring of a horse and donkey) is an example of this type of post-zygotic barrier.
(What is Reduced Hybrid Fertility?)
To determine how closely related two species are on a tree, you should follow the branches back to this specific point.
What is the most recent Common Ancestor?)
A bird’s wing and a butterfly’s wing are examples of this type of structure.
(What are Analogous Structures?)
If two species have very similar amino acid sequences in their proteins, it suggests they shared a common ancestor at this relative time.
(What is Recently?)
A river changing course and splitting a population of flightless insects would lead to this type of speciation.
(What is Allopatric Speciation?)
Birds that do not mate because they have different songs or dances are experiencing this type of isolation.
(What is Behavioral Isolation?)
True or False: The order of the "tips" (taxa) from left to right tells you exactly how closely related species are.
(What is False?)
While they look different on the outside, a bat's wing and a human's arm are homologous because they share this.
(What is a Common Ancestor?)
The evolution of this type of organism provides a "direct observation" of evolution happening in real-time in hospitals.
What is Antibiotic-Resistant Bacteria?)
Polyploidy (extra sets of chromosomes) is a common cause of this type of speciation in plants.
(What is Sympatric Speciation?)
This pre-zygotic barrier occurs when two species live in the same general area but occupy different roles/areas inside that area, like one living in water and the other on land.
Habitat Isolation