Geology & Fossils
This type of rock forms when sediments build up in layers, often trapping fossils within them.
Sedimentary Rock
These diagrams, built using DNA or protein comparisons, show how species are related through evolution.
Phylogenetic Trees
Fossils of Lystrosaurus found in Africa, India, and Antarctica provide evidence for this geological process, which explains why related species can be found on different continents.
Continental Drift
These are structures in different species that are similar because they were inherited from a common ancestor, even if their functions differ.
Homologous Structures
Small changes in when or how long a developmental gene is active can cause big differences in an organism’s shape or size. This type of evolutionary change is called a change in developmental ______.
Timing (or heterochrony)
In undisturbed rock layers, fossils found deeper underground are ______ than fossils found closer to the surface.
Older
As populations become isolated and evolve independently, these random genetic changes build up over time, creating genetic differences.
Mutations
Unrelated species in similar environments may independently evolve similar traits, such as cacti in the Americas and euphorbs in Africa. This type of evolution is called ______.
Convergent Evolution
Structures that perform similar functions in different species but evolved independently due to similar environmental pressures are called ______.
Analogous Structures
Some organisms, like water fleas, can grow protective “helmets” in response to predators. This ability to change development in response to the environment is called ______.
Developmental Plasticity
This process describes when minerals replace organic material in a buried organism, preserving it as a fossil.
Fossilisation
This concept describes how the steady rate at which mutations accumulate can be used to estimate when two species diverged.
Molecular Clock
Islands often have species found nowhere else. The evolution of multiple species from one ancestor to exploit different niches in such environments is called this.
Adaptive Radiation
An example of a homologous structure is the forelimb of mammals, which may function for walking, grasping, swimming, or flying, but shares the same basic bone arrangement because of ______.
Common ancestry
Evo–devo helps explain how entirely new body parts, such as feathers, flowers, or limbs, evolve. These new structures often appear when the organism’s ______ is modified.
Developmental System/Process
This dating method allows scientists to determine whether a fossil is older or younger compared to others, but not its exact age.
Relative Dating
By studying specific genetic markers such as SNPs or microsatellites, scientists can track this process in which one population splits into two genetically distinct groups.
Speciation
This term describes species that are found only in a specific geographic location, such as many animals and plants on islands.
Endemic Species
These are anatomical features that have lost most or all of their original function over evolutionary time, such as the human tailbone or whale pelvic bones.
Vestigial Structures
This concept explains how changes in the timing, location, or level of gene activity during development can create new traits or structures, leading to evolutionary change.
Changes in Gene Expression
(or heterotopy/heterochrony)
When scientists discover fossils that appear out of order in rock layers, they might infer that this geological event has occurred, disrupting the normal sequence of strata.
Geological disturbance (such as folding, faulting, or overturning of rock layers)
This process, in which two different species interbreed, can be studied using molecular techniques to understand its impact on speciation and gene flow.
Hybridisation
Desert plants that evolve traits like water-storing stems and spines do so because these traits increase survival in their specific role in the ecosystem. This role of a species in its environment is called its ______.
Niche
When comparing the forelimbs of a human, a cat, a whale, and a bat, scientists notice that all share a similar arrangement of bones, even though they perform different functions. This observation provides evidence for this principle in __________, also called decent with ________.
Evolution / Descent with modification
Even organisms with similar genes can look and function differently depending on how development is controlled. These changes show that evolution can act on ______ as well as DNA.
Developmental regulation