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BIOLOGY AS > Mod 4 Chap 10: Classification and Evolution > Flashcards

Mod 4 Chap 10: Classification and Evolution Flashcards

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1
Q

Describe classification.

A

The act of arranging organisms into groups based on their similarities and differences.

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2
Q

Describe the method of the biological classification of species most commonly used today.

A 
The Hierarchal Classification System:
- contains 7 taxonomic groups ordered into hierarchy:
Kingdom
Phylum
Class
Order
Family
Genus
Species

A mnemonic to help remember this:

Kids
Prefer
Candy
Over
Fancy
Green
Salads

BUT: now Domain is used above Kingdom in the Hierarchal classification system.

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3
Q

Describe why we classify organisms / species.

A
  • to identify species
  • to predict characteristics
  • to find evolutionary links
  • convenience + more manageable
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4
Q

Describe how we classify organisms / species (today, after using just five kingdoms in past).

A
  • organisms split into 3 different domains:

Archae / Bacteria / Eukarya

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5
Q

Describe how we name species.

A

The Binomial System of Naming Species.

  • developed in 18th cent by Carl Linnaeus
  • aka ‘Binomial Nomenclature’
  • works by giving all species a scientific name of two parts
  • First word: indicates organism’s genus (the genetic name), has a capital letter
  • Second word: indicates organism’s species (the specific name)
  • whole name always written in italics
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6
Q

Give some advantages of using the Binomial Naming System of Species.

A
  • helps to avoid the confusion of using common names

- ensures scientists the world over and discussing same organism

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7
Q

Describe the features that classify organisms into the kingdom of Prokaryotae.

A
  • unicellular
  • no nucleus / other membrane bound organelles
  • a ring of naked DNA
  • small ribosomes
  • no visible feeding mechanism, nutrients absorbed through cell wall / produced by photosynthesis

Examples: bacteria: Bacillus anthracis

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8
Q

Describe the features that classify organisms into the kingdom of Protoctista.

A
  • mainly unicellular
  • a nucleus + other membrane bound organelles
  • some have chloroplasts
  • some are sessile, others move by cilia / flagella / ameboid mechanisms
  • nutrients acquired by photosynthesis (autotrophic feeders) / ingestion of other organisms (heterotrophic feeders) / both

Examples: Algae, Protozoa

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9
Q

Describe the features that classify organisms into the kingdom of Fungi.

A
  • unicellular / multicellular
  • a nucleus + other membrane bound organelles + cell wall mainly composed of chitin
  • no chloroplasts / chlorophyll
  • no mechanisms for locomotion
  • most store food as glycogen
  • saprotrophic feeders - acquire nutrients from absorption, mainly from decaying material

Examples: mushrooms, mounds, yeast

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10
Q

Describe the features that classify organisms into the kingdom of Plantae.

A
  • multicellular
  • a nucleus + other membrane bound organelles + cell wall composed of cellulose
  • all contain chlorophyll
  • most don’t move
  • nutrients acquires by photosynthesis - autotrophic feeders
  • store food as starch

Examples: mosses, ferns, flowering plants.

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11
Q

Describe the features used to classify organisms into the kingdom of Animalia.

A
  • multicellular
  • a nucleus + other membrane bound organelles
  • no chloroplasts
  • move w/ aid of cilia / flagella / contractile proteins, sometimes in form of muscular organs
  • nutrients acquired by ingestion - heterotrophic feeders
  • food stored as glycogen

Examples: reptiles, birds, mammals

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12
Q

Describe recent changes in leading to new classification systems.

A
  • early classification systems used observable features to classify organisms into groups
  • but, problems caused as scientists didn’t always agree on relative importance of diff features, + groups based solely on physical features may not show how related organisms are
  • SO, classification systems now based on observable features along w/ other evidence telling us how closely related organisms are
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13
Q

Describe the evidence that is used in and has lead to new classification systems.

A
  • embryological evidence used (similarities in early stages of an organisms development)
  • fossil evidence
  • molecular evidence (involves analysing similarities in proteins and DNA, more closely related organisms = more similar their molecules are)
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14
Q

Describe how this evidence has lead to new classification systems such as the three Domains of life, which clarify relationships.

A
  • three domain system groups organisms using differences in sequences of nucleotides in cells’ ribosomal RNA (rRNA), + cells’ lipid structure + sensitivity to antibiotics
  • observation of these differences made possibles through advances in scientific techniques
  • under this system: organisms classified into three domains and six kingdoms

Three domains: Archaea / Bacteria / Eukarya

  • organisms classified into these domains by their form of rRNA and diff ribosomes

Six kingdoms:

Old Prokaryotae kingdom divided into two: 1) Archaebacteria and 2) Eubacteria
Then other 4 are: 3) Protoctista, 4) Fungi, 5) Plantae and 6) Animalia.

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15
Q

Describe the features of the rRNA and ribosomes used to classify organisms into the domain of Eukarya.

A
  • have 80s ribosomes

- RNA polymerase (responsible for most mRNA transcription) contains 12 proteins

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16
Q

Describe the features of the rRNA and ribosomes used to classify organisms into the domain of Archaea.

A
  • have 70s ribosomes

- RNA polymerase of diff organisms contains 8 - 10 proteins + is v similar to eukaryotic ribosomes

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17
Q

Describe the features of the rRNA and ribosomes used to classify organisms into the domain of Bacteria.

A
  • have 70s ribosomes

- RNA polymerase contains five proteins

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18
Q

Describe the new kingdom of Archaebacteria derived from the old of Prokaryotae.

A
  • aka ancient bacteria

- can live in extreme environments: e.g. Hot thermal vents, anaerobic conditions, + highly acidic environments

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19
Q

Describe the new kingdom of Eubacteria derived from the old of Prokaryotae.

A
  • aka true bacteria
  • found in all environments
  • most bacteria are of eubacteria kingdom
20
Q

Describe phylogeny.

A
  • name given to evolutionary relationships between organisms
21
Q

Describe phylogenetics.

A
  • the study of the evolutionary history of groups of organisms.
  • reveals which group a particular organism is related to + how closely related these organisms are
22
Q

Describe the relationship between classification and phylogeny.

A
  • classification can occur without knowledge of phylogeny
  • but it is objective of many scientists to develop a classification system that also correctly considers phylogeny of organisms
  • phylogeny can be done without reference to classification
  • classification uses knowledge of phylogeny in order to confirm classification groups are correct or causes them to be changed
23
Q

Describe evidence for the theory of evolution by natural selection.

A

A number of sources used to study evolution:

  • palaeontology - study of fossils + the fossil record
  • comparative anatomy - study of similarities + diffs between organisms’ anatomy
  • comparative biochemistry - similarities + diffs between chemical make up of organisms
  • molecular evidence: DNA - organisms that diverged away from eachother more recently should have more similar DNA, as less time passed for changes in their DNA sequences (evolution) to occur, + this what scientists found
  • molecular evidence: Proteins + other molecules - similarities in molecules also provide evidence, sequence of amino acids in proteins, and antibodies, are compared. More recently diverged organisms from eachother have more similar molecules
    (So is mainly evidence for divergent evolution)
24
Q

Describe the different types of variation.

A
  • Interspecific variation: variation between members of different species, the widest type of variation
  • Intraspecific variation: variation / differences between organisms within a species
25
Q

Describe genetic causes of variation, and give examples of genetic variation.

A

This is an organisms genetic material - differences in the genetic material (genes + alleles) an organism inherits from its parents leads to genetic variation. Several causes for genetic variation in a population:

  • Alleles: genes have diff alleles. W/ a gene for a particular characteristic, diff alleles produce diff effects, so individuals in a species population may inherit diff alleles of a gene
  • Mutations: changes to DNA sequence + so to genes can lead to changes in proteins that are coded for, this can affect physical + metabolic characteristics, resulting in variation
  • Meiosis: gametes (sex cells: ovum + sperm) produced by meiosis in organisms reproducing sexually. Each gamete relieves half genetic content of parent cell, this genetic material inherited = mixed up by ‘independent assortment + crossing over’, leading to gametes showing variation
  • Sexual reproduction: offspring inherits alleles from each of parents, so each individual produced differs from parent. (This why = much more greater variation in sexually reproducing organisms than asexually, (asexual = clones, so variation only happens through mutations))
  • Chance: result of chance as to which two gametes combine in sexual reproduction (aka random fertilisation) , so individuals produced differ from siblings as each contains unique combination of genetic information

Examples:

  • tongue rolling ability
  • eye colour
26
Q

Describe environmental causes of variation, and give examples of environmental variation.

A
  • all organisms affected by environment, but plants may be affected more than animals by environment in which they live, due to lack of mobility

Examples:

  • presence of scars on your body
  • ability to speak diff languages
  • tattoos / piercings
27
Q

Describe environmental AND genetic causes of variation, and give examples of genetic and environmental variation.

A
  • in most cases variation = caused by combination of both environmental + genetic factors
  • ‘nature vs nurture argument’: many characteristics caused by both, so diff to investigate + conclude about causes of a variation, e.g. Cause of variation in intelligence = genetics / environment?

Examples:

  • skin colour
  • height
  • hair colour
28
Q

State the two ways variation can be described, and give variation examples of both.

A
  • Discontinuous Variation: A characteristic that can only result in certain discrete values. Variation determined purely by genetic factors is discontinuous.

E.g. An animals sex / gender; either male / female only, human blood groups

  • Continuous Variation: A characteristic that can take any value within a range. Variation determined by both genetic factors environmental factors are continuous

E.g. Height

29
Q

Describe palaeontology as evidence for the theory of evolution by natural selection.

A
  • fossils of the simplest organisms e.g. Bacteria are found in oldest rocks, but fossils of more complex organisms e.g. Vertebrae are found in more recent rocks - this supports evolutionary theory that simple life forms gradually evolved over an extremely long period of time period into more complex ones
30
Q

Describe comparative anatomy as evidence for the theory of evolution by natural selection.

A
  • presence of homologous structures provides evidence for divergent evolution (describing how from a common ancestor, diff species have evolved, each w/ a diff set of adaptive features)
31
Q

Describe comparative biochemistry as evidence for the theory of evolution by natural selection.

A
  • molecular sequences of a particular molecule are compared from two species to discover how closely related they are (by looking at order of DNA bases / order of amino acids in a protein)
  • species more closely related have more similar DNA and proteins
32
Q

What are variations?

A

The differences in characteristics between organisms.

33
Q

Describe how discontinuous and continuous variation is graphically represented.

A

DISCONTINUOUS:
- normally represented using a bar chart, but can be a pie chart

CONTINUOUS:
- data for continuous characteristics collected in a frequency table, then plotted onto a histogram, curve then drawn to show trend

34
Q

Describe how continuous variation’s data ends up distributed when plotted on a graph, and describe the characteristics to identify this distribution.

A
  • usually result in production of a bell-shaped curve (aka normal distribution curve), so data said to be normally distributed.

Characteristics of normal distribution:

  • mean, mode + median are the same
  • distribution has a ‘bell shape’ that is symmetrical about the mean
  • 50% of values = less than mean, + 50% = greater than mean
  • most values lie close to mean value, no. of individuals at extremes are low
35
Q

Describe standard deviation.

A
  • a measure of how spread out data is, greater the standard deviation = greater the spread of the data
  • a characteristic w/ a high standard deviation = a large amount of variation

(Practice questions), (see worked example in textbook pg 253)

36
Q

Describe adaptations.

A

Characteristics that increase an organisms chance of survival and reproduction in its environment.
Can be divided into three groups:

  • anatomical adaptations: physical features (internal + external)
  • behavioural adaptations: way an organism acts, can be inherited / learnt from parents
  • physiological adaptations: processes that take place inside an organism

Many adaptations fall into more than one category.

37
Q

Describe some examples of Anatomical adaptations.

A
  • body coverings: e.g. Hair / scales / spines / feathers / shells, to help: stay warm / provide protection / waxy cuticle on plants = prevents water loss
  • camouflage: outer colour of an animal allowing it to blend into its environment = more diff for predators to spot it = protection
  • teeth: shape + type of teeth animals have are related to its diet, to help digest / and kill food
  • mimicry: copying another animals appearance / sounds allows harmless animals to fool predators into think it’s posing us / dangerous
  • Marram grass: a xerophyte plant that has adapted to live in environment w/ little water but reducing its rate of transpiration w/: curled leaves minimising SA, stomata sunk into pits so less likely to open + lose water, thick waxy cuticle reducing water loss through evaporation
38
Q

Describe some examples of Behavioural adaptations, and the two main categories they fall into.

A
  • Survival behaviours
  • courtship: many exhibit elaborate behaviours to attract a mate
  • seasonal behaviours: enable organisms to cope w/ changes in environment, include: migration + hibernation

Two main categories of behavioural adaptations:

  • Innate / instinctive behaviour: ability to do this = inherited through genes
  • Learned behaviour: adaptations learnt from experience / from observing other animals

But many adaptations = combination of both innate and learned.

39
Q

Describe some examples of physiological adaptations.

A
  • poison production: many reptiles produce venom to kill prey, + plants produce poisons in leaves to protect themselves from being eaten
  • antibiotic production: some bacteria produce antibiotic to kill other species
  • water holding: useful in for plants + animals to survive without access to water for long periods of time
40
Q

Describe analogous structures.

A

Structures that have adapted to perform the same function but have a different genetic origin.

41
Q

Describe how anatomical adaptations provide evidence for convergent evolution.

A
  • convergent evolution takes place when unrelated species begin to share similar traits that evolve because organisms adapt to similar environment or other selection pressures

Examples of convergent evolution:
- marsupial + placental mammals

42
Q

Describe the mechanism by which natural selection can affect the characteristics of a population over time.

A
  • selection pressures = factors that affect organisms’ chances of survival / reproductive success (ability to produce fertile offspring)
  • organisms best adapted to environment = more likely to survive + reproduce
  • so natural selection means these organisms will be more common in population, + characteristics of poorly adapted organisms to environment are not passed onto next gen, so less of population will display characteristics of weaker organisms
43
Q

Describe exactly how natural selection works.

A
  • organisms within a species show variation in their characteristics, caused by differences in their genes (genetic variation)
  • organisms w/ the characteristics best adapted to a selection pressure e.g. predation / competition / disease, have increased chance if surviving + successfully reproducing
  • less well adapted organisms die / fail to reproduce = process known as ‘survival of the fittest’
  • successful organisms pass allele encoding advantageous characteristic onto offspring
  • this process then repeated for every gen, so over time, proportion of individuals w/ advantageous adaptation increases, so frequency of allele coding for this characteristic increases in population’s gene pool
  • over long periods of time, many gens + often involving multiple genes, this process can lead to evolution of new species
44
Q

Describe how evolution in some species has implications for human populations.

A
  • MRSA (Methicillin Resistant Staphylococcus aureus) has developed resistance to many antibiotics
  • this because bacteria reproduce v rapidly + so evolve in relatively short time
  • when bacteria replicate, DNA can be altered, usually resulting in bacteria dying
  • however mutations can arise, and did in some ‘S aureus’ that provided resistance to methicillin
  • when bacteria exposed to this antibiotic, resistant individuals survived + reproduced, passing alleles for resistance on, non resistant individuals dies, so overtime no. of resistant individuals in population increased

Other examples:

  • peppered moths
  • sheep blowflies
  • flavobacterium
45
Q

Describe a phylogenetic tree.

A

A diagram used to represent the evolutionary relationships between organisms.
Are branched diagrams showing that different species have evolved from a common ancestor.
Earliest species is found at the base of the tree and the most recent at the tips of the branches.
Produced by looking at similarities + differences in species’ physical characteristics + genetic makeup.

46
Q

Describe some advantages of phylogenetic classification.

A
  • produces a continuous tree , whereas classification requires discrete taxonomical groups, so w/ phylogeny scientist not forced to put organisms into a specific group they don’t quite fit
  • Hierarchal nature of Linnaean classification can be misleading as implies diff groups within same rank are equivalent

BIOLOGY AS (12 decks)

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