Symmetry in Biology By Ashlen Mezrahi Radial Symmetry
Symmetry in Biology By Ashlen Mezrahi
Radial Symmetry: Characteristics ● Taxon Radiata - polyphyletic assemblage of different phyla of the Animal kingdom ● Top and bottom ● Mouth ● No head ● No rear
Radial Symmetry: Jellyfish C 4 v D 4
Special Case: Echinodermata ● Starfish, sea urchins, and sand dollars ● Bilateral symmetry at the larval stage ● Fivefold symmetry as adults ○ Pentamerism ○ Five parts; 72° apart Larval Stage: C 2 v
Fivefold symmetry in Echinodermata (C 5 v)
Bilateral Symmetry ● 99% of animals ● Mirror image; left and right side ○ Sagittal Plane ● Internal organs asymmetrical ● Evolved trait over 500 million years ago C 1 v
Bilateral Symmetry: Evolutionary importance ● Forward Movement ○ Seeking food, shelter, home, and reproductive mates ○ Active, directed movement requires an elongated body form with head (anterior) and tail (posterior) ends ● Development of a head and the concentration of sensory organs
Bilateral Symmetry (C 1 v)
Symmetry = Fitness ● Symmetrical Faces “more attractive” ○ Healthier; genetically fitter ■ Asymmetry: depression, anxiety, headaches and even stomach problems ○ Easier for the brain to recognize ● Experiments with birds and insects revealed that females prefer to mate with males possessing the most symmetrical sexual ornaments ○ Female barn swallows prefer males with long, symmetrical tail feathers
Facial Symmetry: Average Example
Very Symmetrical Face
Many more complicated symmetrical shapes in nature! Example- Platonic Solid: Icosahedron 2) Clorophyll protein of a pea 3) Circogonia Icosahedra Radiolaria 4) Radilarian organism 5) Aids virus
Sources https: //www. livescience. com/4002 -symmetry-nature-fundamental-fact-human-bias. html https: //simple. wikipedia. org/wiki/Symmetry_(biology) https: //en. wikipedia. org/wiki/Symmetry_in_biology https: //en. wikipedia. org/wiki/Radiata http: //study. com/academy/lesson/types-of-symmetry-in-animals. html https: //www. pinterest. com/pin/557109416380865419 http: //jwilson. coe. uga. edu/EMT 668/EMAT 6680. 2002. Fall/Nazarewicz/7210_final_2/7210_Project/ https: //quizlet. com/14788158/ab-2 -flash-cards/
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