20 Questions
What is the main characteristic of vestigial organs?
They were functional in ancestors but non-functional or reduced in descendants
What is an example of a vestigial organ in humans?
Appendix
What is the term for the sudden appearance of vestigial organs in highly evolved organisms?
Atavistic organs
What is the significance of the structure and function of organelles in eukaryotic cells?
They are the same in all eukaryotic cells
What is the result of mixing blood from evolutionarily close animals?
Formation of a precipitate
Which of the following is an example of evidence from comparative anatomy?
Vestigial organs
What is the significance of the presence of human ABO blood types in other primates?
It indicates a recent common ancestor
What is the term for organs that have a similar structure and function in different species?
Homologous organs
What do fossils support according to the concept of biological evolution?
The gradual evolution of life on the earth
What is the classification of living organisms based on?
Evolutionary relationship
What is the ancestor of algae and plants according to the evolutionary history?
Unicellular prokaryotes
What is the fundamental unit of life, which is the same in all eukaryotic cells?
Cells
What is the result of mixing blood from evolutionarily close animals?
Precipitation
What is the characteristic of the evolution of animals from prokaryotes?
From unicellular to multicellular
What is the significance of a tadpole's excretion of ammonia?
It indicates its evolutionary relationship with fish
What is the term for the study of fossils that provides evidence for biological evolution?
Paleontology
What type of evidences are provided by the study of fossils and comparative anatomy?
Direct evidences
What is the main purpose of genome sequencing in the study of evolution?
To determine the evolutionary relationships between organisms
What is the term for organs that are similar in structure and function between different species, but have different functions?
Homologous organs
What is the term for organs that are present in a reduced or vestigial form, but have lost their original function?
Vestigial organs
Study Notes
Evidences from Comparative Anatomy
- Vestigial organs are remnants of functional organs in ancestors that have lost their function in descendants
- Examples:
- Appendix in humans, which was functional for digestion in ancient herbivorous humans, but lost its function as humans started eating easily digestible food
- Wisdom teeth (3rd molar) in humans, which are fully developed and functional in other primates
- Atavistic organs are vestigial organs that suddenly appear in highly evolved organisms
- Example: Tailed human babies, resembling primate ancestors
Evidences from Cell and Molecular Biology
- The structure and function of organelles in all eukaryotic cells are the same, indicating a fundamental unit of life
- Blood precipitation test: Blood of evolutionarily close animals forms a precipitate when mixed together
- Human ABO blood types are also present in other primates (gorilla, orangutang, chimpanzee)
- Biochemical recapitulations: Developmental stages of an organism resemble those of its evolutionary ancestors
- Example: Tadpole (larval form of frog) excretes ammonia like fish, while adult frog excretes urea
- Genome sequencing reveals the evolutionary relationships between different species
Evidences from Palaeontology
- Fossils support the idea that life has gradually evolved on Earth
Evolution of Life on Earth
- Unicellular organisms evolved into multicellular organisms
- Evolution of plants from prokaryotes to multicellular organisms
- Evolution of animals from prokaryotes to invertebrates (insects, molluscs, crustaceans) and vertebrates
This quiz covers vestigial organs, organs that were functional in ancestors but non-functional or reduced in descendants. Examples include the appendix and wisdom teeth in humans.
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