Evolution by Stephen Baxter (British, 2003)

Summary:
We are back in the historical era. Here we meet Purga, a kind of squirrel that lives among the dinosaurs. Purga used to have a family, however, a stronger male came in and killed her partner and offspring, and now she is with him and has his child. In the meantime, they see that something is approaching Earth, something big and full of colors and when it hits, they only see destruction everywhere. The first to fall are the dinosaurs, the Earth is covered in ashes and it is almost impossible to breathe. Purga and her children survive, not so her new mate. They take cover in a cave, nonetheless, as it is all covered with dust, there is nothing to eat nor to drink. Little by little her family begins to die; in the end, there is only Purga and her daughter. A few years later, the weather has changed and new green land begins to appear. Purga and her daughter go out of the cave and begin to reconnect with the other survivors. Purga’s daughter leaves her mom so she can go with another group of animals and Purga dies alone. Then we meet Purga’s descendants, each one of them giving new knowledge to their future offspring. For example, they become bipedal, a few million years later they began to have names- which were simple roars-, then they began to crate and use tools, the language began to develop, the sense of family began to spread, religion saw its dawn, but most importantly, the sense of war and fight was the one that was present all the time. 
 Then we have a small time jump into the future to the year 2031, where we met Joan and Alyce a pair of scientific women who went to a convention in Papua New Guinea, in here a group of scientifics are going to talk about the future of the Earth, so they start what they think is the missing link - which according to the description turns out to be Purga. 
 Then we have another time jump back to the past where the famine is taking a lot of lives among different communities, so they began to develop agriculture and fishing, then new ways of transportation such as small not which will help them to find new lands in which the community may grow. With these advances now they began to have contact with other communities, the markets and trades began to be a thing, and war, in order to gain new lands and goods, is a common thing. This is a breaking point because we began to know the Hommo Sapiens Sapiens, for example, we see the birth of proto-Indo-European, they think before they act, and although they used to have strong feelings, they tend to leave them in second place. So, we land on Rome at the downfall of the Roman Empire where two Roman philosophers are discussing how things are going to change. One of them has made an important discovery, a set of bones of what he calls the ”old man” but before he takes it to long, he is murdered. The bones are the vestige of the Neanderthal. 
 We are back in the future with Joan and Alyce, but now we know the circumstances. They are at the airport because the volcano Rabaul is active and no one in the city can move, moreover, Joan is pregnant and near her due date. The convention was an. Emergency call since earthquakes are all over the world, pollution, floods and other natural disasters are on it's high, so they have to find a way to survive this. While they are expressing their points of view and their ideas, they are kidnapped by a group of rebels that no longer see salvation. Luckily, they are saved on time, however, Joan begins labor at the same time the volcano explodes. Joan is transported by helicopter to the nearest hospital, meanwhile, Alyce tells her that the robots that Ian Maughons sent to Mars were a success. 
 Another jump in time to an unknown date in the future where we met a man that they name Snowy, who is confused since he has just woken up from hibernation, moreover, it seems that humans have gon extinct except for him and his fellows. The problem is that there are four men and only one woman, they used to be the last hope of humans. One day when Snowy was on an expedition he encounters a girl, yet she is no longer human because she is naked and doesn't know how to speak. When he returns to his camp the only remaining woman has escaped, and another disturbing thing is that Mars no longer exists. Snowy and the others set different ways since now they have come to the conclusion that they are the last ”human” beings. Snowy follows the girl he found in the woods and her tribe although he never speaks to them. On a side note, they tell us that the robots were working on Mars till they no longer got an answer from humans, they have explored and exploited Mars, so they set off to space. And now Mars does not longer exist. 
 Not only that, a new asteroid named Eros, found by scientists a long time ago, is now approaching Earth. It wouldn't be a problem if Mars would still be there, but now without him, the asteroid is going to strike Earth. While on Earth time goes on, now some female humans are fertile and can have offspring, some others can't. But it doesn't matter because Eros hits Earth. This collision causes a new distribution of the land called New Pangea. Most of the continents have vanished and now is a small portion of land. Very slowly, Earth began to stop its movement around the sun, and photosynthesis began to decay. The world is dying very slowly. 
 The last human offspring is Ultimate. Ultimate is different because she no longer has nipples and is completely covered in an orange fur, there are no more males and no more mothers. A huge tree is the provider of everything -shelter, food, family- and everyone sees him as a God. The tree leaves Ultimate pregnant, however, Ultimate doesn't know what to do. She has the baby, leaves her with the tree and goes out in an exploration. Nonetheless, the tree begins to attack her and attack a friend she made on the way. She hurriedly returns to her branch and finds out that her baby is missing, she sees more movement of the tree and discovers that the tree has taken her child and is killing her. Ultimate tries to save her, but her friend stops her before the tree kills him. Ultimate comes to terms that this is the end, she allows the tree to kill her baby and her. After her death, there is no longer human life. 
 In the end, we go back with Joan and her daughter Lucy who are heading toward the Galapagos Islands, since it is the last place on Earth that seems quiet and where Lucy can learn a lot of things. Joan then says that there is nothing else to do except to live the moment and learn the best of it.

Another summary:
This story sets the reader in Montana, North America in a place name Circa sixty five million years before 2003, when all the continents were stuck together (Pangea), in this period,when the dinosaurs still ruled the earth, there was a mammal of the race purgatorius that looked like that of a squirrel, but a little bit reptilian, All mammals were small during the reign of the large reptiles of that time, mostly all mammals were insectivores or opportunistic carnivores. At that time Purga had a mature age for her species and was the mother of 2 young. Life was hard for mammals, Purga lost the male who had fathered her young. Purga wa hungry, and needed food to be able to produce milk for her young, but the food did not abound, which is why she needed to venture further, to the point that she was forced to leave the safety of the forest to roam the great plains full of dinosaurs, but there was no tub to take much risk; not far away she found a dinosaur nest full of eggs that were being devoured by other small mammals. Purga was clever, even though she did not have a very large brain, she was able to emulate emissions such as remorse and also layers of reasoning to some extent, although she was still an animal guided by instinct. But she knew that those eggs had been laid by someone, and that it might be dangerous to approach, but she was too desperate and set to pass up the opportunity. Like the rest of the animals that were devouring the eggs, she placed herself in position and began to eat. But the animal that had laid the eggs returned. This dinosaur was a troodon (a carnivore). All the animals fled successfully, except Purga, she was eating so enthusiastically that she did not immediately sensed the presence of that dinosaur mother. Purga got up and saw the troodon looking at her, it was a small animal with swollen cheeks and with an eyesight that looked full of blood and pieces of troodon´s developing pups. This troodon was also smart, one of the few dinosaurs smart enough to go crazy. And his madness had been unleashed by that image of purga devouring his little . maybe that's why her name meant Wounding Tooth Purge ran and passed through those plains full of giant herbivorous trying to lose Wounding Tooth. Purga manage to get away from Wounding Tooth and end up on the beach. But that wouldn't be the end of the problem, Wounding Tooth would remember her forever. Purga had acquired an enemy. The next day purga return to his burrow,but something was wrong, her burrow was stinking of blood, the blood of his children. Wounding Tooth who killed his young, she came to the burrow following the traces of her smell and there she still stood, waiting for purga, purga and ran, by a blow of luck she manage to lose Wounding Tooth once more,arriving at the same beach as the night before, she make an attempt to burrow in the sand, lay down, and began to occupy that great intelligence that she had to emulate sadness and regrets, her species would continue, but not his dependents, not his blood. A few months passed, and began to glimpse stars that grew larger and larger, were meteorites, the same meteorites that would trigger the extinction of the dinosaurs, would soon collide in Mexico, specifically in Yucatan, which at that time was still under the sea. But no one thought of those stars, no one cared, not even purga. But curiously Wounding Tooth was the most aware of this phenomenon, and by that I mean that she was only able to recognize the constant change in the size of those lights. But she didn't really think about them, nore the catastrophe it would bring, she just saw them. Back then. Purga had formed a new family, had two young and his companion, he had no name, and purga did not give him a name, but if she had done so it would surely have been "second". Things were still unrifles for mammals, and purga and second were no exception. So they went out together in search of food, but found nothing but bad luck. Second was caught and devoured by a peteradon and purga had to continue the search. But the bad wasn't over, Wounding Tooth had found her, it had been a long time, but Wounding Tooth hadn't forgotten purga. Purga didn't run so lucky this time, she was in an open space and couldn't lose Wounding Tooth. Wounding Tooth plaundthes over immobilizing her,it seemed the end of purga. But strangely purga felt no fear, even though she was aware that she would die, she felt a kind of peace. She had lived longer than the average lifespan of his species, and had managed to breed a healthy litter, his purpose had been fulfilled. she could die in peace. But she didn't, another peteradon took Wounding Tooth. And purge was free, even though she was ready to die. She managed to get back to his burrow, but something was wrong. Again it smelled of blood, it was the blood of their young again. From the burrow came a male of the same species as purga. Attracted by the smell of his burrow. He could have noticed that there was a healthy female in it capable of reproducing. The female was useful, but the offspring were not. If he killed the young then the female could devote herself entirely to the young he would give her. The young were left over. It was a purely logical matter for the male. But purga could not simply go on with life, she had already lost her young twice and was already old. Purge shreds in rage and attracts that male with a mouth painted with the blood of his young. But the male was big and fat. The male pushed her. Purga left, The male followed her. It took her 3 days to accept the new relationship and incubate new young. It was hard. It was life. Some time later it finally happened. The meteorites entered the atmosphere,split during the fall, but most of the meteorites fell in Yucatan. A place that had once been full of Marian life from one moment to the next became dry land,the forests began to burn, the dinosaurs fled the fire and ended up falling into the sea where they drowned. The smoke was so thick that anybody could see through it, some dinosaurs intoxicated. And the herbivores had run out of food, many died and the herds dissolved. The future of the great dinosaurs was already written. But it wasn't better for some animals like mammals. In Contrast, most marine animals followed their lives without much change. They weren't too affected by wildfires. And purga (now an old woman), she was in her burrow along with a couple of pups and her companion "Third". Purge smelled the smoke, she came out and saw the fire, knowing it would not be safe to stay where they were anymore. She decided that the best choice was a rocky mountain that was on one side of her mountain. Then purga, accompanied by Third and one of her young called last (her other young felt fear from the outside and stayed in the burrow, purga did not see him again). They arrived successfully and made a burrow. But the meteorite had also hit a piece of the north pole, so the seas rose and the temperature dropped dramatically. It started an ice age. This affected purga´s family , they had no food. Again Third wanted to act, he knew that they would not last long, and he came to the conclusion that they should eat last. If the meat of last could keep the parents a little more time alive, enough to be able to reproduce again, then last should be slaughtered. But purga managed to decipher his intentions, and she intervened. Purga knew she was very old. Perhaps she could not mate again, this calf was the last, the only calf she had left, her only descendant, her blood (that one day, that line of descendants would end in humanity). Purge attacks third, protecting her daughter. And third did not insist anymore. Time passed and purga and last were prowling what was left of what was once a great forest. Third died of hypothermia a long time ago and did not accompany them. Suddenly a ray of hope hit them. There was a dinosaur. A herbivorous dinosaur. The last of its kind. She, weakened and pregnant,trying priserv the last of her species. Following the tradition she made a nest on the ground as best she could, and began to lay the eggs. Many broke when they touched the ground, and the eggs that had survived the fall would not do so in the hands of an army of mammals. The dinosaur was too weak to defend her eggs, she was too weak to do anything, she was too weak to get on with life. And so, the last big reptile fell. It took her a while to die. Even alive and conscious the little animals pounced on her, she felt the pricks of her teeth in her belly, eventually she died. Purge and last were among those little animals, eating what was left of the previous era. Among the animals were a group of the purga’s species. Last went with them. Not purga. She was too old to mate. Finally purga is alone. She approached a surviving tree and swabs a low burrow. Purge. A female who lived longer than most of her species. And she successfully created one daughter whose descendants would be humanity. She had succeeded, purga fulfilled her mission, felt calm and happy. And that burrow under the tree became his grave.

Another summary:
Baxter describes the evolution of each generation of humankind, how we survived each phase of the Earth just as the asteroid that extinguished the dinosaurs, ice ages, fires, and droughts, how we developed consciousness (and started lying and manipulating other people), intellectual capacities and cultural creativity like drawing and dancing. It all starts with the primate line leading from humans nowadays to humans in the future. From Purga, the first form of humankind, who lived in the dinosaur's era; to Far and her family, who were the first ones to talk; to Pebble, who was the first one to experience love and the pain of loss; to Ja'an who was the first one to have a name; to Juna who fought for having her child; to Snowy who witnessed how every form of humankind had disappeared; to the paleontologist Joan and her daughter Lucy, who lived to witness how Mars disappeared and how another planet was being repopulated without any trace of any former culture or technology made by humans.

World view: The world portrayed in the story is an hypothetical society which seems to be worse than the one the author lives in.
Future projections: Sees the future as potential to reform a reality that once seemed unchangeable.
Ideology: Portrays the enforcement of justice in a positive manner and has faith in human capacity to build a better future.
Characters, plot and writing style: A perfectly planned social order derives on the personal satisfaction and psychic well-being of the characters.
Classification: Dystopia