The top-down direction of both individual and phyletic development represents a realistic link between individual and large scale development, as noted by K. S. Thomson. The shape of the developmental life span is curvilinear. The entire life span of individual animals is a manifestation of development. The rise and subsequent decline is an invariant characteristic of lifelong individual development. This orderly sequence is isomorphic to life-long development in individual organisms.
All individual organisms show signs of senescence if they live long enough.
Phyletic lineages of higher, complex animals begin to show signs of decline and aging after they reach and pass their maximum growth and development, and will eventually die if they do not first become extinct. The resemblance between large-scale sequence of changes covering millions of years and the sequence of changes in early embryonic and lifelong development of individual organisms is quite astounding. I argue that it cannot be a meaningless coincidence that so many phyletic patterns of change in the fossil record are found to resemble patterns of development found in individual organisms. These similarities are surely not trivial or merely coincidental. On the contrary, they point to a deep unity between the overarching historical processes of development, which I have called macro-development, and small scale individual development.