Final answer:
Life histories evolve through trade-offs, with examples such as early versus late reproduction and differing strategies of K-selected versus r-selected species, reflecting a balance between fecundity and parental care shaped by natural selection and environmental adaptation.
Step-by-step explanation:
Physiological and ecological trade-offs are integral to the evolution of life histories, shaping how species allocate energy toward growth, maintenance, and reproduction. Early versus late reproduction illustrates a physiological trade-off where species like guppies reproduce quickly at a small size, reducing their defense against predators, while larger fish like sharks allocate energy towards growth, risking death before reproducing. This trade-off is pivotal in filling ecological niches and maximizing fitness.
Similarly, demographic-based population models uncover ecological trade-offs where K-selected species invest heavily in few offspring for a stable environment, while r-selected species, such as dandelions, produce many offspring, adapting to unpredictable conditions. Each species' life-history strategy, from semelparity to iteroparity, reflects a trade-off between fecundity and parental care influenced by natural selection and environmental adaptation. Predation and reciprocal evolutionary responses further drive these life-history patterns, enforcing a balance between reproductive success and survival.