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IB Biology HL > UNIT 5 - Evolution and Biodiversity > Flashcards

UNIT 5 - Evolution and Biodiversity Flashcards

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1
Q

List the three main domains

A
  • prokaryotes - bacteria
  • extremophiles - archaea
  • eukaryotes
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2
Q

Distinguish the three main domains based on the presence of introns

A

bacteria - rare/absent
archaea - present in some genes
eukaryote - frequent

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3
Q

Distinguish the three main domains based on the presence of histones associated with DNA

A

bacteria - absent
archaea - proteins similar to histones bound to DNA
eukaryote - present

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4
Q

Define evolution

A

process by which living organisms are formed by gradual change frm previous organisms

in other words process of cumulative change in the heritable characteristics of a population

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34
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35
Q

Define and state an alternative name for artificial selection

A

process by which all the plants and animals used by humans have been developed from wild species by selecting individuals with desirable traits and breeding from them

selective breeding

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35
Q

Define a fossil

A

remnant of past life uncovered from the crust of earth

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35
Q

List the main ways of gaining evidence for evolution

A
  • study of fossils
  • artificial selection in the production of domesticated breeds
  • study of the comparative anatomy of groups of organisms
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35
Q

State the characteristics of homologous structures

A
  • similar in fundamental structure
  • similar in position and development but not necessarily in function
  • similar because of common ancestry
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35
Q

State the characteristics of analogous structures

A
  • resemblance in function
  • differing in fundamental structure
  • illustrating only superficial resemblances
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35
Q

Define natural selection

A

the mechanism by which better adapted organism survive to produce a greater number of viable offspring which has the effect of increasing their proportion in the population so that they will become more common

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35
Q

Define analogous structures

A

similar in structure but different in evolutionary origin

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35
Q

Define neo-darwinism

A

an essential restatement of the concepts of evolution by natural selection in terms of mendelian and post-mendelian genetics

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35
Q

State an example of a homologous structure

A

limbs of vertebrates

all of which appear to be modifications on the ancestral five-fingered limb

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35
Q

State an example of analogous structure

A

wings of birds and insects
similar only in their function as areofoils

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35
Q

State the ways of arising the gene for antibiotic resistance

A
  • spontaneous mutation
  • conjugation
  • infection by a virus that has picked up the gene for antibiotic-resistance in another host
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35
Q

Define adaptive radiation and give an example of it

A

rapid evolutionary diversification of a single ancestral line

e.g. beak types seen in the finches of the Galapagos islands which have specialized beak shapes depending on their primary source of nutrition

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35
Q

Define an autopolyploid

A

individual that has more than two chromosome sets that are all derived from a single species

35
Q

State reasons for the rapid evolution of multiple antibiotic resistance in the last few decades

A
  • widespread use of antibiotics both for treating diseases and in animal feeds used in farms
  • rapidly reproducing bacteria
  • huge populations of bacteria with increasing chance of mutations
35
Q

Define a gene pool

A

different genes in an interbreeding population at a given time

35
Q

Define and state the reason for overproduction of offspring

A

organisms produce many more offspring than survive to be mature individuals which in the wild leads to their competition for resources

the majority of organisms fail to survive and reproduce as they are limited by environmental factors

36
Q

Define species

A

a group of potentially interbreeding populations with a common gene pool that is reproductively isolated from other species

36
Q

State the two forms of polyploidy

A
  • autopolyploid
  • hybrid offspring
36
Q

State the reasons for evolution to occur

A
  • mutations introducing new alleles
  • selection pressures favoring the reproduction of some varieties over others
  • barriers to gene flow
36
Q

Define allele frequency

A

frequency of a particular allele as a proportion of all the alleles of that gene in a population

36
Q

Define a geographic isolation of the populations

A

separation of the two populations by geographic barriers such as rivers, mountains or oceans

36
Q

State the ways of reproductive isolation of populations

A
  • temporal
  • behavioral
  • geographic
37
Q

State the two types of speciation

A
  • sympatric
  • allopatric
37
Q

Define allopatric speciation

A

a physical barrier separates a species into geographically isolated populations which then develop independentently under the different conditions and eventually become unable to interbreed

37
Q

Define sympatric speciation

A

a gene pool can become divided without the population being geographically split

37
Q

Define temporal isolation

A

a form of reproductive isolation caused by differences in breeding schedules

38
Q

Define behavioral isolation

A

presence or absence of a specific behavior prevents reproduction from taking place

38
Q

Define polyploidy

A

accidental origination of specie during cell division resulting in extra sets of chromosomes

38
Q

Define hybrid offspring

A

form of polyploidy occurring when two different species interbreed

most such hybrids are sterile

39
Q

State the reason for a hybrid offspring being sterile

A

the set of chromosomes from one species cannot pair during meiosis with the set of chromosomes from other species

40
Q

Define an allopolyploid

A

a fertile polyploid of a sterile hybrid

41
Q

State the three models of selection

A
  • directional
  • disruptive
  • stabilizing
41
Q

Define directional selection

A

Favours variants that are at one extreme of the distribution

42
Q

Define disruptive selection

A

Favours variants at both ends of the distribution

42
Q

Define stabilizing selection

A

removes extreme variants from the population and preserves intermediate types

43
Q

Define phyletic gradualism

A

evolution occurs by the gradual accumulation of small changes and the intermediate stages of evolution not represented by fossils testifies to the incompleteness of the fossil record

43
Q

State the two patterns of macroevolution

A
  • phyletic gradualism
  • punctuated equilibrium
44
Q

Define speciation

A

evolutionary process by which two related populations diverge into separate species

44
Q

Define punctuated equilibrium

A

evolutionary history consists of geologically long periods of stasis with little or no evolution interrupted or punctuated by geologically short periods of rapid evolution

45
Q

State the principle of the binomial system

A

scientific name of two Latin words

first - generic name - noun - designates the genus

second - specific name - adjective - names the species

examples:
homo sapiens = modern humans

46
Q

State the principle of naming the closely related organisms

A

have the same generic name but differ in their species name

47
Q

Define taxonomy

A

science of classification of organisms into a hierarchal scheme based on their similar characteristics

48
Q

Distinguish natural versus artificial organism classification

A

natural classifies an organism basen on its evolutionary relationships (i. e. kingdom to species)

artificial classification groups organisms which show similar characteristics due to convergent evolution (i. e. all organisms with wings)

49
Q

State the taxonomic rank starting from domain

A

domain
kingdom
phylum
class
order
family
genus
species
common name

50
Q

State with reason the mode of nutrition of an Amoeba

A

holozoic as it feeds after trapping food in food vacuoles

51
Q

State with reason the mode of nutrition of a Plasmodium (malarial parasite)

A

parasitic - feeds on contents of liver cells and red cells

52
Q

State with reason the mode of nutrition of a Paramecium

A

holozoic - feeds after trapping food in food vacuoles

53
Q

State a characteristic feature of the plasma membrane of the Paramecium and Euglena

A

strengthened by additional protein - a pellicle

54
Q

State with reason the mode of nutrition of Saccharomyces

A

saprotrophic - feeds on nectar via fermentation

55
Q

State the characteristic features of the plantae kingdom

A
  • photosynthetic
  • eukaryotic organisms with a wall containing cellulose
  • autotrophic - manufacturing sugars by photosynthesis in their chloroplasts
  • store starch
  • permanent vacuoles
56
Q

State the principle of a life cycle of plants

A

two generations/stages

  • gametophyte generation producing gametes
  • sporophyte generation forming spores
57
Q

State the four main phyla of green plants

A
  • bryophytes - non-vascular plants
  • ferns - seedless plants (but vascular)
  • conifers - seed and vascular plants
  • flowering plants - seed and vascular plants
58
Q

State the characteristics of bryophytes

A
  • poorly adapted to terrestrial conditions land plants - damp environments
  • stems with radial symmetry
  • stems with bilateral symmetry, no lignin
  • no true leaves or roots
  • no cuticle so no protection from water loss
  • reproductive structures - sporangium
59
Q

State the characteristics of ferns

A
  • well adapted to terrestrial conditions
  • leaves with cuticle
  • roots non woody stems
  • divided leaves
  • height up to 20 m
  • reproduction through sporangia
60
Q

State the characteristics of conifers

A
  • trees (100 m), shrubs
  • strong stems
  • woody (lignin) stems
  • waxy narrow needle like leaves
  • vascular system (tracheids)
61
Q

State the characteristics of phylum

A
  • dominant group of land plants
  • roots and stems
  • leaves
  • vascular bundles (xylem and phloem)
  • waxy cuticle
  • ovules in an enclosed carpel structure
62
Q

Distinguish between monocotyledons and dicotyledons in terms of seed-leaves and veins in leaves

A

monocotyledons have parallel veins in their leaves and single seed-leaf in the embryo of the seed

dicotyledons have net veins in their leaves and two seed leaves in the embryo

DICOTYLEDONS
- embryo in seed has 2 cotyledons
- broad leaves with veins forming a network
- vascular bundles of stem in a ring
- branched roots
- parts of the flowers (sepals, petals, etc.) in fours of fives

MONOCOTYLEDONS
- embryo in seed has 1 cotyledon
- bayonet or strap-shaped leaves with parallel veins
- vascular bundles of stem numerous and scattered
- unbranched roots
- parts of the flowers (sepals, petals, etc.) in threes.

63
Q

State the characteristics of the animal kingdom.

A
  • multicellular, eukaryotic organisms with heterotrophic nutrition
  • highly specialized cells (organs usually)
  • nervous system present
  • bilateral symmetry
64
Q

State the life cycle of animals

A

diploid life cycle
with haploid gametes produced by adults in meiosis

65
Q

Define cephalization

A

an evolutionary trend in the animal kingdom toward centralization of neural and sensory organs in the head or anterior region of the body

66
Q

State the six main phyla of non-vertebrates of the animal kingdom

A
  • sponges
  • jellyfish and sea anemones
  • flatworms
  • segmented worms
  • mollusk
  • jointed-limbed animals
67
Q

Define and state the characteristics of sponges (the porifera)

A

simplest multicellular animals, structurally little more than colonies of cells, are aquatic and mostly marine animals

  • simple sac-like structures of cells in two layers arranged around a central gastric cavity
  • entirely lack nervous system
    cells specialize in feeding, structural support or reproduction
  • can reproduce asexually by budding and sexually forming a free-swimming larva
  • no body layers but rather aggregate of different cell types
  • no mouth or anus
68
Q

State the characteristics of cnidaria and give example of such

A

e. g. jelly fish, corals

  • 2 layers of the body plan
  • radial symmetry
  • single entrance that serving as both cavity for circulating the respiratory gases and nutrients
  • secondary consumers - posses nematocysts to disable prey
69
Q

Define nematocysts

A

stinging cells with toxins used to disable prey

70
Q

State the material the skeleton of corals is made of

A

CaCO3

71
Q

State the characteristics of Platyhelminthes (the flatworms)

A
  • flat, unsegmented animals
  • triploblastic organization
  • no cavity in the middle layer but a mouth and a gut present
  • no anus
  • feeding by scavenging or predating on other small animals
  • no circulatory system but ease in diffusing to most cells because of the thin flat body
  • flame cells present
  • hermaphrodite organization
  • this phylum contains many important parasites like tapeworms
72
Q

Define triploblastic organization

A

body built from three cell layers

73
Q

State the function of flame cells in Platyhelminthes

A

excretion and regulation of water and ions in the body

74
Q

Define a hermaphrodite organization

A

both male and female reproductive organs present in one individual

75
Q

State the specialized characteristic features of a tapeworm.

A

the head with specialized structures - suckers, hooks, spines, - that hatch on to the intestinal wall

76
Q

State the characteristic features of the segmented worms (phylum Annelida)

A
  • 3 layers of the body plan
  • bilateral symmetry
  • hydrostatic skeleton
  • cephalization
  • metameric segmentation
  • ringed segments of the body
  • mouth with a gut connected
  • anus present and separate
  • skin surface for gas exchange - moist body surface
  • ventral nerve cord running the length of the body
77
Q

Define metameric segmentation

A

each segment of the body contains the same pattern of nerves, blood vessels and excretory organs

78
Q

State the characteristic features of Mollusca and give an example of such

A

e. g. snails, limpets, mussels, octopuses

  • most aquatic, few terrestrial
  • soft, flexible bodies
  • little or no segmentation
  • usually covered by a shell
  • compact body shape means ineffective diffusion for the transport of nutrients thus they have gills or occasionally lungs and a well-developed blood circulation
  • rasping, tongue-like radula used for feeding
79
Q

State the characteristic features of Arthropoda (jointed limbed animals) and give an example of such

A

e. g. crustaceans, centipedes, insects

  • segmented bodies, covered by a hard external skeleton made of chitin and jointed limbs
  • exoskeleton doesn’t grow with the animal - molting
  • open blood circulation - haemocoel cavity surrounding all the organs and a tubular heart pumping blood into the haemocoel
  • ventral nerve cord with nerves running to each segment (concentration of nerves in front of the body)
80
Q

Define moulting

A

periodical shedding of an exoskeleton and its exchange for a larger one

81
Q

Define a clade

A

a group of organisms believed to comprise all the evolutionary, descendants of a common ancestor

82
Q

Define cladistics

A

method of cloudifying living organisms based on the construction and analysis of cladograms

83
Q

Define a cladogram

A

evolutionary tree showing points at which clades diverged from a common ancestral form

84
Q

State where does the evidence come from for a cladogram

A

biochemical data:

  • number of differences in the DNA base sequence of a gene
  • number of differences in the amino acid sequence of protein
85
Q

State the correlation stemming from a cladogram

A

a positive correlation between the number of differences between two species and the time difference since they diverged from a common ancestor

86
Q

Define the node and clade in relation to cladogram terms

A

nodes - the tree branches from the coloured circles - as the tree spits at nodes it indicates when the species have diverged

clade - groups of organisms sharing a common ancestor

87
Q

Define a molecular clock

A

differences in the base sequence of DNA is used to deduce how long ago species split from a common ancestor

88
Q

State the requirement needed for the statement in a dichotomous key

A

each statement must be qualitative and not relative.

e. g. not “long leaf blade” but “length of leaf blade greater than width”

IB Biology HL (6 decks)

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