Midterm Exam #1

Question 1

What are phylogenetics?

Answer 1

The study of the evolutionary history and relationship of an organism or a group of organisms.

Question 2

What is a branch point/node?

Answer 2

The point where a split occurs, which represents where a single lineage evolved into a distinct new one.

Question 3

What are polyphyletic groups?

Answer 3

Groups that are created based on similarities that are not the result of common ancestors (ex. analogous traits).

Question 4

What are paraphyletics groups?

Answer 4

Groups that exclude some of the descendants. This is due to errors in assignment or species to the correct common ancestors.

Question 5

What are the characteristics of life?

Answer 5

Order, Sensitivity/Response to the Environment, Reproduction, Adaptation, Growth and Development, Regulation/Homeostasis, Energy Processing, Evolution, Classification

Question 6

What is a taxonomy?

Answer 6

The science of classifying organisms to construct internationally shared classification systems with each organism placed into increasingly more inclusive groupings.

Question 7

What are cladistics?

Answer 7

A system that sorts organisms into clades: groups of organisms that descended from a single ancestor based on shared traits.

Question 8

What is maximum parsimony?

Answer 8

A principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that’s consistent with the facts.

Question 9

What is catastrophism?

Answer 9

A geological doctrine that changes in the earth’s crust have in the past been brought about suddenly by physical forces operating in ways that cannot be observed today.

Question 10

What is gradualism?

Answer 10

The theory that evolution occurs slowly but steadily.

Question 11

What is uniformitarianism?

Answer 11

The principle that states that geologic processes that occur today are similar to those that have occurred in the past.

Question 12

What is convergent evolution?

Answer 12

Similar traits evolving independently in species that don’t share a common ancestry.

Question 13

What is genetic drift?

Answer 13

A change in allele frequencies caused by random events.

Question 14

What is the founder effect?

Answer 14

The reduced genetic diversity that results when a population is descended from a small number of colonizing ancestors.

Question 15

What is sexual selection?

Answer 15

Natural selection arising through preference by one sex for certain characteristics in individuals of the other sex.

Question 16

What is a clade?

Answer 16

A group of species that includes an ancestral species and all its descendants.

Question 17

What is a synamorphy?

Answer 17

Shared character as a result of inheritance from a common ancestor. Used to define a clade and denote the difference from the clade to another groups/species that aren’t part of that clade.

Question 18

What is a fossil?

Answer 18

The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.

Question 19

What is an allele?

Answer 19

The term used to describe the different versions of a gene.

Question 20

What are the steps for the scientific method?

Answer 20

Observation, Question, Hypothesis, Prediction, Experiment, Result

Question 21

What is a sister taxa?

Answer 21

Groups that share an immediate common ancestor. Two lineages stemming from the same branch.

Question 22

What is natural selection?

Answer 22

The more prolific reproduction of individuals with favourable traits that survive environmental change because of those traits, which lead to evolutionary change.

Question 23

What is relative fitness?

Answer 23

The ability of one organism to reproduce as compared with the same ability in another organism.

Question 24

What is the bottleneck effect?

Answer 24

The loss of genetic variation that occurs after outside forces destroy most of a population. Only a few individuals survive and these few reproduce in the next generation. Gene frequency in the next gen is different from the previous, and rare alleles are more likely to be lost due to drift.

Question 25

What is gene flow?

Answer 25

The flow of alleles in and out of a population due to the migration of individuals or gametes. There’s an increase in variation within a population and a decrease in variation between populations.

Question 26

What is non-random mating?

Answer 26

When individuals select mates based on proximity or phenotype.

Question 27

What is genetic variation and how is it measured?

Answer 27

The diversity of alleles and genotypes within a population. Often measured by determining proportions of heterozygotes or the number of alleles at various locations.

Question 28

What is taxonomy?

Answer 28

The science of naming and classifying organisms.

Question 29

What is a polytomy?

Answer 29

A branch in a phylogenetic tree with more than two lineages.

Question 30

What is homologous?

Answer 30

Traits with characters that are shared among taxa as a result of shared common.

Question 31

What is stabilizing selection and what happens from it?

Answer 31

A type of natural selection in evolution that favours the average individuals in a population and reduces extremes. It eliminates harmful mutations, the mean of the population stays the same (variance decreases) and there’s little to no evolutionary change (maintains genetic variation).

Question 32

What is disruptive selection and what happens from it?

Answer 32

Favours individuals at both extremes of the phenotypic range. Results in polymorphism (two or more divergent phenotypes) and maintains genetic variation.

Question 33

What is directional selection and what happens from it?

Answer 33

A type of natural selection that where the extreme phenotype is favoured. Results in a response to steady change in the environment,, frequency distribution of alleles shifts (can cause loss of allelic varieties, loss of genetic variation) and a direction shift in the mean of the population (statistical/phenotypic variance may stay the same).

Question 34

What is analogus?

Answer 34

Traits that appear to be similar characters but have not occurred as a result of common ancestry, but rather an evolutionary adaptation to similar environments.

Question 35

What is a symplesiomorphy?

Answer 35

Shared derived trait within a clade. Not useful for creating branches within a clade, but indicate that they have a common ancestor.

Question 36

What is a gene?

Answer 36

Sections of DNA that contribute to certain traits, characteristics of functions.

Question 37

What is allele frequency?

Answer 37

The number of times an allele occurs in a gene pool, compared to the total number of alleles in that pool for the same gene.

Question 38

What is a population?

Answer 38

Individuals of a species living within a specific area.

Question 39

What are monophyletic groups?

Answer 39

Groups that link species based on shared derived traits and contain the common ancestor and all its descendants.

Question 40

What is Lamark’s theory?

Answer 40

acquired characteristics