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Bio 112 > Test 1 > Flashcards

Test 1 Flashcards

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Biology 101 flashcards
1
Q

Natural Selection

A

reproduction of individuals with favorable traits that survive environmental change due to those traits.

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2
Q

3 principles that result in natural selection

A

most characteristics of organisms are inherited

more offspring are produced than are able to survive, so resources for survival and reproduction are limited causing competition

Offspring vary among each other in regard to their characteristics and those variations are inherited.

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3
Q

genetic diversity comes from two mechanism, _______ and __________

A

mutation and sexual reproduction

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4
Q

adaptation

A

a heritable trait that helps an organism’s survival and reproduction in its present environment

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5
Q

divergent evolution

A

two groups of the same species evolve different traits within those groups in order to accommodate for differing environmental and social pressures.

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6
Q

convergent evolution

A

similar phenotypes evolve independently in distantly related species due to similar environments

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7
Q

homology

A

similarity that exists in species due to common ancestry. Includes genetic homology (similar DNA, RNA nucleotide sequences), developmental homology (similar embryotic stages), and structural homology (similar adult form)

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8
Q

phylogenetic tree

A

branching diagram that depicts ancestor-descendant relationships among taxa

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9
Q

Evidence for evolution

A
  1. Life on earth is ancient
  2. Fossil record shows a change in life over time, including extinctions
  3. Transitional features document change in traits through time
  4. Vestigial traits are common.
  5. Characteristics of populations vary within species and are observed changing.
  6. Similar species are found in the same geographic area.
  7. Related species share genetic, developmental, and structural homologies
  8. Formation of new species from preexisting species can be observed today.
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10
Q

species

A

individual organisms that interbreed to produce fertile, viable offspring

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11
Q

gene pool

A

collection of all the gene variants in the species

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12
Q

speciation

A

formation of 2 species from 1. Can occur in 2 mechanisms: allopatric speciation or sympatric speciation.

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13
Q

Sympatric speciation

A

Sympatric speciation occurs without a physical barrier to gene flow. This is more common in plant species and usually caused by changes in chromosome numbers

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14
Q

Allopatric speciation

A

geographic separation of a species causing divergence. Two categories: dispersal and vicariance

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15
Q

Dispersal allopatric speciation

A

when a few members of a species move to a new area

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16
Q

Vicariance allopatric speciation

A

a natural situation arises that physically divides organisms of the same species.

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17
Q

Inferences Darwin made

A

all species have reproductive potential for exponential population growth, but populations tend to remain stable de to limited resources. Since there is natural variation among species and that variation is heritable, adaptation will occur

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18
Q

The modern sythesis

A

combines darwin’s natural selection with mendels hereditary patterns, as well as particulate transfer (chromosomes) and structure of DNA molecules.

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19
Q

gene pool

A

total number of alleles for any gene in a population (number of individuals in population x2)

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20
Q

Hardy-Weinburg Theorem

A

demonstrates that allele frequencies do not change through meiosis alone, only shuffles alleles, doesn’t change proportions. This does not happen in nature. It is a null hypothesis. Assumes no natural selection, large population size, isolated populations, random mating, and no mutation.

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21
Q

Allele frequency

A

percentage that A and a occurs to add to 100%

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22
Q

micro-evolution

A

population-scale changes in allele frequencies. Can include natural selection, genetic drift, gene flow, selective mating, and mutation

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23
Q

genetic drift

A

random changes in allele frequency from gen. to gen. b/c reproductive events are samples of the parent population. This is more pronounced in smaller and more segregated populations as shown through bottleneck and founder effects

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24
Q

founder effect

A

when a small group of individuals break off from a larger population. These small groups often do not represent full allele distribution.

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25
Q

bottleneck effect

A

large percent of species dies off leaving reduced allele frequency.

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26
Q

gene flow

A

mixing of alleles between populations through immigration and emigration

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27
Q

directional selection

A

phenotypes at one extreme of the range are most successful. (pattern, color, form, metabolic process)

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28
Q

diversifying selection

A

multiple, but not all, phenotypes are successful. Patchy environments. Population begins to fragment and new species begin to diverge

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29
Q

stabilizing selection

A

intermediate phenotypes are most successful. (homogenous environments, stable conditions) Range of variation is reduced

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30
Q

preservation of natural variation

A

diploidy, balanced polymorphism, neutral variation

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31
Q

diploidy

A

2 alleles for every gene. Even if aa is eliminated, Aa is preserved

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32
Q

balanced polymorphism

A

heterozygote advantage (sickle cell anemia), frequency dependent selection (when the fitness of a genotype depends on its frequency), and phenotypic variation(multiple morphotypes favored by patchy environment)

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33
Q

neutral variation

A

genetic variation that has no apparent effect on fitness.

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34
Q

population

A

a localized group of individuals of one species

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35
Q

fitness

A

reproductive success (amount of healthy, successful offspring)

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36
Q

Biological species (basic standard definition)

A

defined by natural reproductive isolation. Individuals that can produce successful offspring are considered the same species. However, cant be used to classify extinct animals and has fuzzy boundaries during divergence.

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37
Q

Morphological species (first way to separate species)

A

defined by differences in form. however, it doesn’t always work due to convergent evolution and natural phenotypic variation. Only way to classify extinct species.

38
Q

Phylogenic species

A

species defined based on evolutionary history. Struggles when there is a lack of fossil record and imperfect agreement on interpretation.

39
Q

Pre-zygotic barriers

A

prevent formation of zygote such as: habitat isolation, behavioral isolation, temporal isolation (timing), structural isolation, and chemical isolation.

40
Q

Post-zygotic barriers

A

prevent successful development of offspring. Hybrids either do not develop properly, cant reproduce due to lack of sexual maturity or viable gametes, or hybrid lineages fail over time.

41
Q

How is speciation, genetic drift, and gene flow affected in a small population

A

speciation is likely to occur more rapidly, more genetic drift, less gene flow.

42
Q

How does sympatric speciation occur

A

mutation or selection pressures, errors in meiosis leading to polyploidy, or successful hybrids (mostly plants)

43
Q

polyploidy

A

one cause of sympatric speciation when a normally diploid cell acquires one or more additional sets of chromosomes.

44
Q

endemic species

A

restricted in distribution to a particular place, generally because they evolved in that place. (only exist in one place)

45
Q

adaptive raditation

A

diversification of a group of organisms into forms filling different ecological niches.

46
Q

macroevolution

A

large phenotypic changes that result from small changes in regulatory genes

47
Q

taxonomic hierarchy

A 
domain
kingdom
division (phylum)
class
order
family
genus
species/epithet
48
Q

human taxonomic classification

A 
Domain- eukarya
kingdom- animal
phylum-chordates
class-mammals
order-primates
family-hominoids
genus-homo
species- sapiens
49
Q

what caused humans to diverge from other primates

A

bi-pedalism and large brain

50
Q

Carolus Linnaeus

A

founder of modern taxonomy (defined kingdoms and morphological similarities)

51
Q

Linnaeus’ taxonomic hierarchy

A

kingdom (only recognized 2 kingdoms), division, class, order, family, genus, species

52
Q

5 kingdom system

A

outdated, developed in 1960s. includes monera, protist, plants, animals, and fungi.

53
Q

3 domain classification system

A

used today; divides life into archaea, bacteria, and eukaryote. Kingdoms are defined by monophyletic lineage

54
Q

features unique to plants

A

chloroplasts, carbs stored as starch, cell wall of cellulose, cell division by formation of cell plate, plasmodesmata, large central vacuole

55
Q

4 major groups of plants

A

mosses, ferns, gymnosperms, and angiosperms.

56
Q

angiosperms

A

flowering plants. 90% of earths modern flora.

57
Q

primary vs. secondary

A

primary wall is produced first and mostly made of cellulose. secondary walls are interior to primary, are produced later, and are lignified and rigid.

58
Q

five major plant cell types

A

parenchyma, collenchyma, sclerenchyma, xylem elements, phloem elements.

59
Q

Parenchyma

A

thin primary wall, no secondary wall. Is bulk of plant body and is responsible for many metabolic and storage functions.

60
Q

Collenchyma

A

thick primary wall, no secondary wall. Supports growing tissues.

61
Q

Sclerenchyma

A

thick lignified secondary wall. Support mature plant parts, often dead at maturity.

62
Q

Collenchyma vs. Sclerenchyma

A

both provide structural support and have thick walls. Collenchyma has a thick primary wall with no lignin while Sclerenchyma has thick secondary wall and is lignified.

63
Q

xylem elements

A

lignified secondary walls, always dead at maturity (open). function to transport water and nutrients to support the plant. Includes tracheids and vessel elements.

64
Q

phloem elements

A

sieve tube members and companion cells. lacks nucleus and ribosomes. function to transport products of metabolism.

65
Q

4 plant tissue systems

A

epidermis, vascular, ground, meristem.

66
Q

epidermis tissue

A

covers outer surface of all plant. Shoot surfaces (above ground) covered with waxy cuticle. Contains stomata and is usually 1 cell layer

67
Q

vascular tissue

A

transports water, solute, and metabolic products. Provides structural support. Includes xylem, phloem, parenchyma, sclerenchyma.

68
Q

ground tissue

A

bulk of plant body (pith, cortex, and mesophyll) mostly parenchyma and provides metabolic, structural and storage functions

69
Q

meristem tissue

A

actively dividing cells that generate all other cell types. Causes indeterminate growth.

70
Q

4 classes of angiosperms

A

paleoherbs, magnoliids, eudicots, monocots

71
Q

what 2 classes make up about 3% of total angiosperms

A

paleoherbs and magnoliids

72
Q

monocot examples

A

grass, iris, orchids, palms

73
Q

eudicots examples

A

broadleaf trees and shrubs, fruits and vegetables, herbaceous flowering plants.

74
Q

characteristics of monocots

A

flower parts in mult. of 3, parallel leaf venation, single cotyledon, vascular bundles in a ring in the roots, and vascular bundles in complex arrangement in the stem.

75
Q

characteristics of eudicots

A

flower parts in mult. of 4/5, netted leaf venation, 2 cotyledons, vascular tissues in a solid core in the roots, vascular bundles in a ring around stem.

76
Q

stomata

A

pores to allow for gas exchange and transpiration

77
Q

indeterminate primary growth

A

elongation of stems and roots

78
Q

indeterminate secondary growth

A

trees expansion in diameter

79
Q

why cant leaves and flowers repair damage

A

they dont exhibit indeterminate growth.

80
Q

where does dedifferentiation most often occur

A

in stems and roots to repair damage

81
Q

auxin-mediated cell expansion

A

Plant cells elongate irreversibly only when load-bearing bonds in the walls are cleaved. Auxin causes the elongation of stem and coleoptile cells by promoting wall loosening via cleavage of these bonds

82
Q

apical meristems

A

cause elongation of roots and stems

83
Q

axillary meristems

A

allows for branching

84
Q

lateral meristems

A

responsible for secondary growth, or increase in stem diameter. called cambiums

85
Q

root cap

A

protects meristem, determines geotropism, and secretes mucigel to enhance nutrient uptake and ease movement. Constantly sheds cells

86
Q

root hairs

A

form as the epidermis fully differentiates. increases surface area

87
Q

primary shoot growth

A

elongation from the tip

88
Q

secondary xylem is

A

wood, annual growth rings are accumulating rings of secondary xylem

89
Q

bark

A

all tissues external to vascular cambium. Inner bark functions as secondary phloem and outer bark varies through maturity

90
Q

cork cambium

A

meristematic tissue that divides to produce cork cells (cells filled with waxy, waterproof suberin)

Bio 112 (4 decks)

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