Midterm 1 Study Guide

Question 1

Contribution of Linnaeus

Answer 1

Linnaeus challenged the Great Chain of Being but placed humans in category with other animals

FATHER OF TAXONOMY
- Systema established the taxonomic practices we still use today:
~ Hierarchical system
~ Binomial nomenclature
~ Typology in biology (essentialism)

Question 2

Contribution of Buffon

Answer 2

Histoire Naturelle (1749) deviated from biblical accounts of creation
- degeneration theory proposed minor improvements/degenerations (from original life forms)
- argued for old Earth

Question 3

Contribution of Cuvier

Answer 3

• established extinction as a scientific fact
• proposed idea of catastrophism
• but did NOT believe that one species could change into another

Question 4

Contribution of Lamarck

Answer 4

Proposed that new species could originate via natural processes
- first fully-articulated theory of evolution driven by complexifying force and adaptive force

Question 5

Who made the first detailed proposal for evolution and how it worked?

Answer 5

Lamarck

Evolution driven by two forces: complexifying force and adaptive force (transmutation and adaptation)

Inheritance of acquired characteristics: first mechanism proposed to explain fit between organism and environment

Transmutation: the idea that a species, as a whole, could change into another, more complex, species

Question 6

Contribution of Hutton and Lyell

Answer 6

Hutton: “Father of Geology”
- concerning the System of the Earth, its Duration and Stability (1785)
(land today was sea floor in the past)
(Timeless and cyclical nature of geology)

Lyell:
- Principles of Geology (1830)
(Uniformitarianism)
- Led to the belief that Earth was much older than people had previously thought

Question 7

What are the two “big ideas” presented by Darwin in Origin?

Answer 7

1.) All living things descend from one or a few original forms of life
2.) Natural selection is the mechanism

Question 8

How does Darwin’s theory of evolution differ from Lamarck’s theory?

Answer 8

Lamarck’s theory was based on the principle that physical changes in individual organisms during their lifetime could be transmitted to their offspring. Darwin’s theory revolves around the idea that populations evolve, not individuals. Because individuals in a population vary, some are better able to survive and reproduce given a particular set of environmental conditions.

Question 9

When was Origin of Species published?

Answer 9

1859

Question 10

What does it mean that “individuals do not evolve?”

Answer 10

Individuals do not evolve since evolution is a “change over time” and these individuals are stuck with the genes they are born with. The changes occur during reproduction, so natural selection acts by shifting the characteristics of the population as a whole and no one individual.

Question 11

What are the observations that Darwin’s theory is based on?

Answer 11

1.) Populations have the potential to increase exponentially
2.) But they generally maintain a stable size
3.) Resources are limited
4.) Variation in all species
5.) Variation is heritable

Question 12

Who was Alfred Russel Wallace?

Answer 12

A naturalist and explorer working in Indonesia that independently comes up with the idea of natural selection (On the Tendencies of Varieties to Depart Indefinitely from the Original Type (1858))

Question 13

Nucleotide

Answer 13

1.) Sugar-phosphate backbone
2.) A base (A, T, C, G)

Question 14

DNA

Answer 14

Deoxyribonucleic acid

• a molecule made up of nucleotides
• carries genetic information

Question 15

DNA triplet

Answer 15

encodes for a specific amino acid

Question 16

mRNA

Answer 16

Ribonucleic acid
- synthesis of proteins

Question 17

RNA codon

Answer 17

translated into an amino acid to create a polypeptide chain

Question 18

Amino Acid (polypeptide chain)

Answer 18

building blocks for proteins

Question 19

Protein

Answer 19

a chain of amino acids (and other stuff) that provides a function in a cell
- folds up into a specific shape
- shape=function

Question 20

Gene

Answer 20

A DNA sequence that codes for a functional RNA product

Outdated: an uninterrupted segment of DNA specifying an amino acid sequence

Question 21

Allele

Answer 21

One of two or more versions of a genetic sequence at a particular region on a chromosome

Question 22

Locus

Answer 22

Location on a chromosome

Question 23

Chromosome

Answer 23

Chromatin condenses into chromosomes when division is about to divide

-DNA organized into genes

Question 24

Meiosis

Answer 24

the process of replicating gamete cells

Question 25

Mitosis

Answer 25

The process of replicating somatic cells

Question 26

Gamete cell

Answer 26

Sex cell (sperm or egg) - haploid (23)

Question 27

Somatic cell

Answer 27

body cell - diploid (46)

Question 28

Polygenic

Answer 28

Descriptor for a phenotypic trait influenced by more than one gene

Question 29

Pleiotropic

Answer 29

Descriptor for a single gene that affects more than one phenotypic trait Ex. ear wax and body odor

Question 30

Polymorphic/polymorphism

Answer 30

The existence of multiple forms - a variant occurring at over 1% frequency in a population or sample

Question 31

Mendel's 4 postulates and laws of inheritance?

Answer 31

1.) Principle of Paired Factors 2.) Principle of Dominance 3.) Law of Segregation 4.) Law of Independent Assortment

Question 32

Principles of Paired Factors

Answer 32

Hereditary characteristics are controlled by particulate unit factors that exist in pairs in individual organisms

Question 33

Principle of Dominance

Answer 33

When an individual has two different unit factors for a characteristic, only one is expressed. That unit factor is dominant over the other, which is recessive

Question 34

Law of Segregation/Purity of Gametes

Answer 34

The paired units of inheritance (chromosomes) segregate and each sex cell receives one copy or the other with equal likelihood

Question 35

Law of Independent Assortment

Answer 35

Chromosomes get split up into gametes independently; the segregation of any given pair of chromosomes does not affect segregation in other pairs of chromosomes, so that a gamete with "maternal" chromosome 1 will not necessarily contain "maternal" chromosome 2

Question 36

What are the 4 forces of evolution?

Answer 36

1.) Mutation 2.) Natural selection 3.) Gene Flow 4.) Genetic Drift

Question 37

Mutation

Answer 37

Source of all variation in populations - A random change in the genetic code, resulting from errors in DNA replication

Question 38

Natural Selection

Answer 38

The phenomenon that increases the frequency of alleles that lead to increased survival and reproduction (fitness) -Proposed by Alfred Russell Wallace and Darwin

Question 39

Gene Flow

Answer 39

Process by which populations of a species exchange alleles (individuals) - introduces new variation into a population - but decreases the difference between populations

Question 40

Genetic Drift

Answer 40

A random change in allele frequency that can occur as a result of sampling error

Question 41

What is the Founder's Effect?

Answer 41

New population formed by a small number of "founding" individuals - founder population unlikely to accurately represent all the genetic variation in original population Because founding population was small, DRIFT QUICKLY increases the frequency of rare variants

Question 42

What is a Bottleneck?

Answer 42

An event that drastically reduces the size of a population such as natural disasters, habitat loss, or overhunting - the consequence of the bottleneck effect is the loss of variation in a population caused by the reduction of allele frequencies In other words: Take an original population of many individuals with lots of genetic variation and then shrinks in size and few individuals can only carry two variants of alleles, causing a huge reduction of genetic diversity even when population increases again

Question 43

How does Founder's effect generate genetically distinct populations?

Answer 43

The small population will have reduced genetic variation from the original population due to genetic drift

Question 44

How does Bottleneck generate genetically distinct populations?

Answer 44

A limited number of individuals survive, resulting in genetic drift to reduce a population's genetic variation...

Question 45

How are the concepts-- fitness, natural selection, adaptation, and evolution-- related?

Answer 45

Through natural selection, individuals more adapted to their environment tend to survive and reproduce better, causing the population to evolve to include those traits (that increased fitness) Without differences in fitness, natural selection cannot act and adaptation cannot occur and evolution cannot take place

Question 46

What are the necessary conditions for natural selection?

Answer 46

1.) The individuals or units of selection must vary (genetic variation) 2.) Some individuals must be more fit than others (differential fitness) 3.) There must be a correlation between the fitness of parents and offspring (heritability)

Question 47

What is the heterozygote advantage? What does it explain?

Answer 47

Fitness of the heterozygote is greater than either homozygote... this explains how a seemingly deleterious allele can be maintained in a population EX. Sickle Cell Anemia allele more resistant to developing Malaria since red blood cells of heterozygotes are less hospitable for the parasite that causes Malaria

Question 48

What is lactase?

Answer 48

An enzyme that breaks down lactose into glucose and galactose (simple sugars)

Question 49

What is lactose?

Answer 49

A disaccharide sugar in milk

Question 50

Is lactase persistence an adaptation? Why or why not?

Answer 50

Yes, the lactose tolerance mutation arose randomly and had a distinct advantage in certain populations that had milk as part of their diet... ** if environment there would make drinking milk an advantage, the gene will continue to be expressed... it isn't normal for mammals to be able to consume and digest milk in adulthood...

Question 51

**Describe one way that human biology (evolution) affects culture?

Answer 51

Differences in skin color resulted in segregation in which not everyone was given equal opportunity in the community

Question 52

Describe one way that human culture affects biological evolution?

Answer 52

Cultures with a history of dairy farming and milk drinking have a much higher frequency of lactose tolerance Only certain people in some cultures are socially acceptable to marry and reproduce with

Question 53

Phenotype

Answer 53

Any observable or measurable feature of an organism

Question 54

Genotype

Answer 54

The genetic makeup of an individual (variants at a specific locus)