2.4 Embryonic Development BYK

A multicellular organism in the early stages of development.

• Zygote

• Embryo

• Fetus

• Chromosome

How does a zygote develop into an embryo?

• cell divisions

• specialize in their...

• As the embryo develops cells...

• structure and function.

• The zygote develops into an embryo as it grows through many...

Undifferentiated cells that can develop into highly specialized cells by turning on and off certain genes. These are the cells that all specialized cells derive from.

• Skin Cells

• Zygote Cells

• Embryonic Cells

• Stem Cells

Why do so many embryos look similar during the early stages of development?

• Scientists believe that all organisms share a common ancestor from which they developed a similar pathway of development.

• Scientists know that all organisms have the same DNA and therefore will look the same in early stages of development.

• Scientists hypothesize that all organisms have the same parents and therefore develop similarly.

• Scientists believe that since all organisms start as one cell they will have the same traits and characteristics.

A rod made of cartilage that runs the length of the embryos body, found in all vertebrates.

• Spinal Cord

• Vertebrae

• Notochord

• Tailbone

Explain why some structures change drastically or even disappear toward the end of development, while others stay consistent throughout development.

• the notochord is replaced with the....

• replaced with structures specific to the species.

• For Example...

• backbone.

• As development continues some structures are...

When parts of different organisms have the same relative position and structure.

• Homosapien

• Homologous

• Homogeneous

• Homozygous

The bones in the picture are very similar, what do you think this suggests?

• These bones suggest that these animals are all mammals.

• These bones suggest that these animals all share descent from a common ancestor.

• These bones suggest that these animals are all able to fly and walk on land.

  
  

• These bones suggest that humans may soon evolve into horses and whales.

Reorder the organisms to match the embryos.

• Human

• Cow

• Horse

• Cat

A field of study that looks at internal and environmental factors that guide how cells look at pieces of DNA in order to make new cells.

• Epigenetics

• Polygenetics

• Human Genome

• Mendelian Genetics