Evolution: Evidence Homologous Body Structures

Evolution: Evidence Homologous Body Structures

Evidence of Evolution

• The Fossil Record

• Geographic Distribution of Living Things

• Homologous Body Structures

• Similarities in Early Development

Evidence of Evolution

• The Fossil Record

• Geographic Distribution of Living Things (Pangea)

• Homologous Body Structures

• Similarities in Early Development

Evidence of Evolution

• The Fossil Record

• Geographic Distribution of Living Things (Pangea)

• Homologous Body Structures

• Similarities in Early Development

Evidence of Evolution

• The Fossil Record

• Geographic Distribution of Living Things (Pangea)

• Homologous Body Structures

• Similarities in Early Development

• homology: A correspondence of structures in two life forms with a common evolutionary origin, such as flippers and hands.

• analogy: The relationship between characteristics that are apparently similar but did not develop from the same structure

• homoplasy: A correspondence between the parts or organs of different species acquired as the result of parallel evolution or convergence.

  
  

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Homologous Body Structures

• Homologous structures are similar structures that evolved from a common ancestor

• The relationship defined between structures or DNA derived from a common ancestor and illustrates descent from a common ancestor.

Multiple Choice

Structures with the same parts have different functions; suggests that organisms share a common ancestry

• vestigial structures

• homologous structures

• adaptive radiation

• fossil

Multiple Choice

What is a structure that is similar across species?

• vestigial
• homologous
• adaptaion
• variation

Analogous structures

• Physically (but not genetically) similar structures that were not present in the last common ancestor.

• Two species that evolved separately (rather than being present in the last common ancestor)

• The wings of a maple seed and the wings of a bird are analogous but not homologous

Multiple Select

What are the most important characteristics of analogous structures?

• Structures that perform the same function

• Structurally different

• Structurally the same

• Structures that perform different functions

Multiple Choice

A category of structures that have a similar function, but are structurally different.

• Homologous structures

• Analogous structures

• Vestigial structures

• Common core structures

Convergent Evolution

• independent evolution of similar features in species of different lineages. 

• The two species came to the same function, flying, but did so separately from each other.

• They have “converged” on this useful trait. Both sharks and dolphins have similar body forms, yet are only distantly related: sharks are fish and dolphins are mammals.

Convergent evolution Ex camera eye

• The cephalopod eye is “wired” in the opposite direction, with blood and nerve vessels entering from the back of the retina, rather than the front for vertebrates.

• In the octopus version, the eye is constructed the “right way out,” with the nerves attached to the rear of the retina. This means that octopi do not have a blind spot.

Parallel evolution

• Convergent is similar to Parallel evolution occurs when two independent but similar species evolve in the same direction and thus independently acquire similar characteristics; for example, gliding frogs have evolved in parallel from multiple types of tree frog.

Divergent Evolution

• Related species evolve different traits

• On a molecular level, this can happen due to random mutation unrelated to adaptive changes.

Multiple Choice

• A=convergent B=divergent C=adaptive radiation
• A=adaptive radiation B=convergent C=divergent
• A=divergent B=convergent C=adaptive radiation
• A=divergent B=adaptive radiation C=convergent

Multiple Choice

• The image shows convergent evolution.
• The image shows divergent evolution.
• The image shows adaptive radiation.
• The image shows homologous structures.

Multiple Choice

• The image shows convergent evolution. 
• The image shows divergent evolution. 
• The image shows adaptive radiation.
• The image shows analogous structures.

Multiple Choice

The three species pictured do not share a common ancestor, yet have evolved to have a similar anatomy and life style. This is an example of ?

• Homologous Structures

• Divergent Evolution

• Vestigial Organs

• Convergent Evolution

Multiple Choice

The three species pictured do not share a common ancestor, yet have evolved to have a similar anatomy and life style. This is an example of ?

• Homologous Structures

• Divergent Evolution

• Vestigial Organs

• Convergent Evolution

Multiple Choice

What type of structure does this image illustrate?

• Homologous structures

• Analogous structures

• Vestigial structures

Vestigial structures

• Vestigial structures have no function but may still be inherited to maintain fitness.

• The formation of goosebumps in humans under stress is a vestigial reflex its function in human ancestors was to raise the body’s hair, making the ancestor appear larger and scaring off predators.

• Vestigial structures are often homologous to structures that function normally in other species

Multiple Choice

The appendix, tailbone, and wisdom teeth are all examples of what type of structure in humans?

• Homologous

• Analogous

• Vestigial

• Modern

Multiple Select

Select the two most important characteristics that distinguish homologous structures.

• Similar bone structures

• Similar function

• Similar embryonic development

• Similar species