add numeric ranges

1 file changed +12 −0

Diff

diff --git a/evolution_data.json b/evolution_data.json
index 789e8f5..97b843a 100644
--- a/evolution_data.json
+++ b/evolution_data.json
@@ -2,6 +2,8 @@
   {
     "periodName": "Earliest Homo (c. 2.8 - 1.8 MYA)",
     "timeRange": "c. 2.8 - 1.8 Million Years Ago",
+    "numericStartYear": -2800000,
+    "numericEndYear": -1800000,
     "narrative": "The story of the Homo genus begins in Africa. This period sees the emergence of early members like Homo habilis, often associated with the first stone tools (Oldowan tradition). These hominins lived in environments of woodlands and grasslands, primarily in Eastern and Southern Africa. Some researchers include Homo rudolfensis in this early phase, with debates on its distinction from H. habilis.",
     "species": [
       {
@@ -33,6 +35,8 @@
   {
     "periodName": "Homo erectus & First Major Dispersals (c. 1.9 MYA - 700 KYA)",
     "timeRange": "c. 1.9 Million - 700,000 Years Ago",
+    "numericStartYear": -1900000,
+    "numericEndYear": -700000,
     "narrative": "Homo erectus (including H. ergaster) appears, a remarkably successful species with a larger brain and body size. They developed more sophisticated Acheulean tools and were the first known hominin to migrate out of Africa ('Out of Africa I'). Key fossil sites like Dmanisi (Georgia) mark this early expansion into Eurasia, eventually reaching East Asia (China, Java).",
     "species": [
       {
@@ -91,6 +95,8 @@
   {
     "periodName": "Rise of H. heidelbergensis & Regional Diversification (c. 700 - 300 KYA)",
     "timeRange": "c. 700,000 - 300,000 Years Ago",
+    "numericStartYear": -700000,
+    "numericEndYear": -300000,
     "narrative": "Homo heidelbergensis emerges, found in Africa and Europe, and possibly Asia. This species is considered a likely ancestor to both Neanderthals (in Europe) and Homo sapiens (in Africa). They were capable hunters of large game, utilized more refined tools (late Acheulean), and adapted to a range of environments, including colder regions in Europe. Late populations of H. erectus persisted in parts of Asia.",
     "species": [
       {
@@ -160,6 +166,8 @@
   {
     "periodName": "Neanderthals, Denisovans & Early Sapiens (c. 400 - 100 KYA)",
     "timeRange": "c. 400,000 - 100,000 Years Ago",
+    "numericStartYear": -400000,
+    "numericEndYear": -100000,
     "narrative": "This period marks the flourishing of Neanderthals in Europe and Western/Central Asia, evolving from European H. heidelbergensis. Denisovans, a sister group to Neanderthals, are known from limited fossils in Asia but wider genetic evidence. In Africa, early anatomically modern Homo sapiens were appearing, with key fossils like Jebel Irhoud (Morocco) and Omo Kibish (Ethiopia) dating to this era. Other contemporary hominins like H. naledi (South Africa) and H. floresiensis (Indonesia) highlight regional diversity.",
     "species": [
       {
@@ -287,6 +295,8 @@
   {
     "periodName": "Homo sapiens Major Expansion & Archaic Admixture (c. 100 KYA - 40 KYA)",
     "timeRange": "c. 100,000 - 40,000 Years Ago",
+    "numericStartYear": -100000,
+    "numericEndYear": -40000,
     "narrative": "This period witnessed major dispersals of Homo sapiens out of Africa, primarily via a 'Southern Dispersal' route along coastal Asia, reaching Australia by ~65-50 KYA. Earlier dispersals into the Levant and Arabia were also significant. During these expansions, H. sapiens encountered and interbred with Neanderthals (in Eurasia) and Denisovans (in Asia), leaving genetic traces in modern non-African populations. Neanderthals and Denisovans were still present but their populations started to decline towards the end of this period. H. floresiensis persisted on its island.",
     "species": [
        {
@@ -395,6 +405,8 @@
   {
     "periodName": "Global Colonization & Late Pleistocene Humans (c. 40 KYA - 10 KYA)",
     "timeRange": "c. 40,000 - 10,000 Years Ago (End of Last Glacial Maximum)",
+    "numericStartYear": -40000,
+    "numericEndYear": -10000,
     "narrative": "Homo sapiens becomes the sole surviving hominin species. This period sees the full colonization of Europe, the peopling of the Americas via Beringia (and possibly coastal routes), and further innovations in technology and art (e.g., cave paintings). The Last Glacial Maximum (LGM, peak c. 26.5-19 KYA) significantly impacted environments and human distributions, creating refugia and influencing migration patterns. Neanderthals, Denisovans, and H. floresiensis go extinct early in this period.",
     "species": [
       {