In what Eons was there very little appearance of new forms of life, how long did they last, and why
was there so little diversification?
What will be an ideal response?
In the Hadean, which lasted 750 million years, the first evidence of life is observed. Atmospheric
conditions were probably not suitable for rapid diversification. No other life forms are observed. In the
Archean, which lasted 1,350 million years, evidence for the first prokaryotes is observed. There
appears to be new forms of prokaryotes that are formed because oxygen starts to build up in the
atmosphere, which is evidence for photosynthesizing bacteria (cyanobacteria) and there is evidence for
both anaerobic and aerobic respiration. In the Proterozoic, which lasted 1.958 million years, there is
evidence of the first eukaryotic forms of life, evolution and diversification of protists, fungi, and the
first soft-bodied animals. Climate conditions were becoming more suitable. Once the Phanerozoic Eon
begins 542 million years ago, new life forms start to evolve more and more rapidly through each
Period.
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Which of the following structures is not associated with the female reproductive component of the plant?
a. Ovary b. Stigma c. Carpel d. Filament e. Style
Reinforcement enhances prezygotic isolation that had begun to develop while the populations were
sympatric.
Indicate whether the statement is true or false.Which of the following is NOT characteristic
of cancer tissue?
a. retention of adhesion proteins b. increased vascular flow c. malformed cytoskeleton d. abnormal chromosome number e. all of these are characteristic of cancer tissue
Four of the five answers listed below are
density-independent factors. Select the EXCEPTION.
a. nutrient supply b. temperature drop c. drought d. volcanic eruption e. hard freeze