There are a few main reasons why plants adapt to the climate in their biome:
1. Survival - In order to persist and reproduce, plants must be able to withstand the conditions they experience, like temperature, sunlight, rainfall, etc. Over time, through natural selection, plants develop traits that enable them to survive in that particular climate.
2. Reproduction - Plants that are able to reproduce successfully will pass on their adaptive traits to offspring. Plants with traits that don't match the local climate will be less likely to reproduce.
3. Competition - Plants compete with each other for resources like sunlight, water and nutrients. Plants that are better adapted to the conditions will generally outcompete less adapted plants.
4. Evolution - Through the gradual process of natural selection and evolution, plants acquire traits that enhance their chances of persisting in that specific environment. Traits that improve survival and reproduction get selected for and become more common.
5. Response to environmental cues - Many plant adaptations involve responses to environmental cues, like day length, that signal the changing of seasons. These cues trigger physiological changes that enable plants to survive through different climatic conditions.
So in summary, plants adapt to their local climate through survival of the fittest - the ones with traits that match the conditions are most likely to persist and reproduce, passing those adaptive traits on to the next generation. This gradual process of adaptation and evolution shapes the kinds of plants we see in different biomes around the world.