BIOSC-101 Lecture Notes - Lecture 17: Molecular Cloning, Polyphyly, Endospore

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blushmallard188

21 Dec 2020

School

Diablo Valley College

Department

Biological Science

Course

BIOSC-101

Professor

wyler

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Document Summary

Explain the importance of distinguishing between homology and analogy. Homologies are phenotypic and genetic similarities due to shared ancestry. The similarity in the number and arrangement of bones in the forelimbs of mammals is due to their descent from a common ancestor with the same bone structure (morphological homology) In general, organisms that share very similar morphologies or similar dna sequences are likely to be more closely related than organisms with vastly different structures or sequences. The more complex two similar structures are, the more likely it is that they are homologous. The more elements that are similar in two complex structures, the more likely it is that the structures evolved from a common ancestor. Same argument applies to the gene level. If genes in two organisms share many portions of their nucleotide sequences, it is likely that the genes are homologous.

Related Questions

Snapping shrimp used to be able to swim from the Atlantic Ocean to the Pacific Ocean by traveling between North and South America. However, when the Isthmus of Panama appeared (a land bridge that connects the Americas), the shrimp could no longer travel between the oceans and evolved into different species. This an example of

sympatric speciation

allopatric speciation

punctuated speciation

genetic drift

10.

Which of the following refers to a structure that is similar because of descent from a common ancestor (e.g. a human leg and a whale fin)?

Analogous structures

Antonymous structures

Synonymous structures

Homologous structures

11.

Artic foxes have white fur and ptarmigan (birds) have white feathers that help them hide in the snow. Given that their common ancestor did not have white fur or white feathers, these structures are most likely

sister structures

homologous structures

divergent structures

analogous structure

12.

Which of the following statements refers to phylogeny?

		The science of studying the transmission of genetic information.
		The science of classifying organisms.
		method used to organize homologous traits to describe phylogenies using common descendent as the primary criterion used to classify organisms.
		The evolutionary history and relationship of an organism or group of organism.

An African monkey has a DNA sequence that is 96.66% similar to a human sequence. According to the molecular clock, about how long ago did the common ancestor for African monkeys and humans live?

2.5â3 million years ago

5â6 million years ago

13â16 million years ago

17â20 million years ago

Humans and chimpanzees have a common ancestor that lived approximately 5 million years ago. Scientists have amassed an impressive collection of fossils for ancestors to modern humans and placed these ancestors in chronological order to observe the changes that occurred as these organisms evolved more human-like characteristics. Which lines of evidence provide the basis for stating that humans and chimps have a common ancestor that lived approximately 5 million years ago?

homologous structures in humans and chimps

DNA sequence similarity

changes in bone structure

vestigial structures in humans

Which description applies to a vestigial structure or trait?

It is the result of convergent evolution.

It represents evidence supporting the common descent and separate types models for modern organisms.

It did not have a necessary function in more ancestral organisms, but it does in more evolved organisms.

It is a type of homologous trait that is found in diverse organisms.

Which organisms are most closely related?

Bears and raccoons, which are both in the order Carnivora

Cougar and lynx, which are both in the family Felidae