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Macroevolution is guided by sorting of interspecific variation ("species selection" [2]), as opposed to sorting of intraspecific variation in microevolution. [3] Species selection may occur as (a) effect-macroevolution, where organism-level traits (aggregate traits) affect speciation and extinction rates, and (b) strict-sense species selection, where species-level traits (e.g. geographical ...
The rate of evolution is quantified as the speed of genetic or morphological change in a lineage over a period of time. The speed at which a molecular entity (such as a protein, gene, etc.) evolves is of considerable interest in evolutionary biology since determining the evolutionary rate is the first step in characterizing its evolution. [1]
The history of life on Earth seems to show a clear trend; for example, it seems intuitive that there is a trend towards increasing complexity in living organisms. More recently evolved organisms, such as mammals , appear to be much more complex than organisms, such as bacteria , which have existed for a much longer period of time.
The tree of life or universal tree of life is a metaphor, conceptual model, and research tool used to explore the evolution of life and describe the relationships between organisms, both living and extinct, as described in a famous passage in Charles Darwin's On the Origin of Species (1859). [1]
In biology, evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organization , from kingdoms to species , and individual organisms and molecules , such as DNA and proteins .
Biology – Science that studies life Evolutionary biology – Study of the evolution of life Evolutionary developmental biology – Comparison of organism developmental processes; Genetics – Science of genes, heredity, and variation in living organisms; Biogeography – Study of distribution of species
Life cycles can be divided into two major stages: growth and reproduction. These two cannot take place at the same time, so once reproduction has begun, growth usually ends. [9] This shift is important because it can also affect other aspects of an organism's life, such as the organization of its group or its social interactions. [8]
Phenotypic or developmental plasticity is the alteration of development through environmental factors. [2] These factors can induce multiple types of variants that increase the fitness of an organism based on the environment they are in. These alterations can be for defense, predation, sex determination, and sexual selection. [2]