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Scrat [10]
3 years ago
9

What index provides evidence of when different types of life evolved on Earth?

Biology
1 answer:
aev [14]3 years ago
4 0

There are all sorts of ways to reconstruct the history of life on Earth. Pinning down when specific events occurred is often tricky, though. For this, biologists depend mainly on dating the rocks in which fossils are found, and by looking at the “molecular clocks” in the DNA of living organisms.

There are problems with each of these methods. The fossil record is like a movie with most of the frames cut out. Because it is so incomplete, it can be difficult to establish exactly when particular evolutionary changes happened.

Modern genetics allows scientists to measure how different species are from each other at a molecular level, and thus to estimate how much time has passed since a single lineage split into different species. Confounding factors rack up for species that are very distantly related, making the earlier dates more uncertain.

These difficulties mean that the dates in the timeline should be taken as approximate. As a general rule, they become more uncertain the further back along the geological timescale we look. Dates that are very uncertain are marked with a question mark.

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Molodets [167]
DNA is made up of polymers and monomers, or nucleotides which have four parts, A, T, G , and C. Transcription is the process when DNA is copied to mRNA. That carries the information for protein synthesis. Translation is the process when ribosomes in the cytoplasm or ER synthesize proteins after the process transcription.

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3 0
3 years ago
Describe the two patterns Wilson observed regarding the distribution of ants on Melanesian islands.
monitta

Answer:

human invasions and expansion/contraction cycles during glacial-interglacial periods

Explanation:

In 1961, the biologist Edward Osborne Wilson studied the distributional, behavioral and morphological characteristics of ants living in the Melanesian archipelago. After his study, Wilson then proposed a hypothesis to explain the biogeographic dynamics of Melanesian ants which has been referred to as the 'taxon cycles'. Taxon cycles are defined by stages of expansion and contraction in the range of distribution of species combined with evolutionary adaptive changes in their ecological niches. These cycles can be represented by historical processes of invasion that resemble human invasions. In the last years, it has been shown that Wilson's hypothesis is supported by predictions obtained by modern methodologies for investigating taxon cycles (i.e., evolutionary phylogenetic methods).

8 0
3 years ago
I need help I’m confused
polet [3.4K]

Answer:

E, A, C, B, D

Explanation:

You weight is the force of gravity pulling you towards earth. A push or pull is a force. Gravity pulls everything down towards Earth. Friction slows things down like a ball rolling. If there was no friction a ball would roll forever. When you push on a door you contact it while using a force, contact force.

5 0
2 years ago
Read 2 more answers
Chromosome is to cactus as gene is to _____.
alexgriva [62]
Chromosome is to cactus as gene is to needle 
3 0
3 years ago
Help please this is hard
Sholpan [36]

the answer is chloroplast

4 0
3 years ago
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