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A Level Biology > Classification and Evolution > Flashcards

Classification and Evolution Flashcards

1
Q

Classification

A

The process of sorting living things into groups of similar organisms. It reflects how closely related they are and evolutionary relationships

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2
Q

Taxonomy

A

The study of the principles behind classification
- study of the differences between species(physical + genetic)

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3
Q

Phylogeny

A

The study of the evolutionary relationships between organisms, the study of how closely related they are

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4
Q

Why we classify organisms

A
  • identify species
  • predict characteristics
  • find evolutionary links
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5
Q

8 taxonomic groups used for classification

A

Domain Largest
Kingdom
Phylum
Class Decreasing variation
Order
Family
Genus
Species Smallest

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6
Q

Binomial nomenclature

A

2 terms are used to denote a species of living organism
First once indicates genus, and the second one is species

E.g. Homo sapiens

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7
Q

Morphological features

A
  • physical characteristics
  • reproductive structures
  • observable traits
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8
Q

Heterotrophic feeders

A

Eat and digest other organisms

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9
Q

Autotrophic feeders

A

Use photosynthesis to make own food

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10
Q

Saprotrophic feeders

A

Digest other organisms outside the body (using enzymes)

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11
Q

How many kingdoms are there

A

5

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12
Q

What are the 5 kingdoms

A
  • animals
  • plants
  • fungi
  • protoctista
  • prokaryotes
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13
Q

Characteristics of each kingdom

A

Animals- eukaryotes, multicellular, heterotrophic feeders, no cell walls, fertilised eggs develop into blastula (multicellular organisms), move freely

Plants- eurkaryoted, multicellular, autotrophic feeders, cellulose cell wall, contain chlorophyll

Fungi- eukaryotes, mostly multicellular (yeast-unicellular), Saprotrophic feeders, chitin cell wall, reproduce with spores, mycelium made of hyphae

Protoctista- eukaryotes, mostly single celled, autotrophic & Saprotrophic feeders, variety of different forms- don’t fit into any other kingdoms, display features of multiple kingdoms

Prokaryotes- no membrane bound organelles, smaller 70s ribosomes, smaller than eukaryotes, may be free living or parasitic
no nucleus- loop of naked DNA, no histones

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14
Q

How many domains are there

A

3

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15
Q

What are the 3 domains

A
  • bacteria
  • archaea
  • eukarya
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16
Q

Characteristics of each domain

A

Bacteria
- 70s ribosomes
- no nucleus- prokaryotic

Archaea
- prokaryotes- have no nucleus
- extremophile

Eukarya
- multicellular
- animal, fungi, plants
- protists with cilia, protists with flagella

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17
Q

Who introduced 6 kingdoms classification and what did they add

A

Carl Woese
- split prokaryotes into archaebacteria and eubacteria

18
Q

Standard deviation

A

• used to measure how spread out a set of data is
• The higher the standard deviation, the more spread out the data is
• E.g. populations with large amounts of variation will have a large standard deviation

high SD= wider curve
low SD= tall curve

19
Q

Standard deviation formula

A
20
Q

Phylogeny

A

The evolutionary relationships between organisms

21
Q

Advantages of phylogenies trees

A
  • doesn’t require scientists to put organisms into groups that they may not fit perfectly into
  • Linnaeus classification can be misleading
  • Linnaean classification cannot be done without reference to phylogeny
  • quantifiable
22
Q

Disadvantages of phylogenetic trees

A
  • extinct species are not considered
  • no timing of events available
  • can’t include prokaryotic species
23
Q

Evidence for evolution (4)

A
  • palaeontology
  • molecular
  • homologous structure
  • antibiotic resistance
24
Q

Evidence: palaeontology

A
  • Fossils show that organisms have changed over time
  • Methods such as carbon dating can be used to work out how old fossils are
  • The oldest rocks contain the simplest species (vice versa)
  • Ecological links, plants before animals consistent with animals needing plants to survive
  • The fossil record shows many organisms that no longer exist but were intermediates between the oldest common ancestors and modern species
25
Q

Problems with fossil records

A
  • fossils don’t always form
  • soft tissues don’t fossilise
  • many haven’t been found
26
Q

Evidence: molecular

A

DNA extracted from fossils
-DNA found in the nucleus of cells can be sequenced and used to provide evidence of evolutionary relationships between species and how the genetic code of species has changed as they have evolved
- shows similarities between organisms if they have a similar base sequence - implies they share a common ancestor

Highly conserved molecules
- similar cytochrome C (protein needed for respiration) primary structure shows similarities between organisms- implies they share a common ancestor
- RNA and DNA

27
Q

Evidence: homologous structures

A

Many modern animal species share a physiological similarity - the pentadactyl limb (5 ‘fingered’) suggesting that they share common ancestors (evidence for divergent evolution)

28
Q

Evidence: antibiotic resistance

A

Due to their fast reproduction rate, bacteria can show evolution in action

1.Population of bacteria with once resistant bacteria
2. Bacteria die apart from the antibiotic resistant bacteria
3. They reproduce and multiply with their antibiotic resistant characteristic
4. Population is all resistant to bacteria

29
Q

Variation

A

Differences in the characteristics between organisms

30
Q

2 types of variation

A

Interspecific- variation between different species
E.g. humans, dogs

Intraspecific- variation within species
E.g dog breeds

31
Q

Causes of variation

A

Genetic
- blood group
- skin colour

Environmental
- tattoos

Both
- weight
- height
- hair colour
- sun tan

32
Q

Causes of genetic variation

A
  • alleles- e.g. dominant or recessive, homo or heterozygous
  • mutations- change in DNA sequence
  • meiosis- independent assortment and crossing over
  • sexual reproduction- offspring are not clones
  • chance- random fertilisation- many gametes are produced
33
Q

Causes of environmental variation

A
  • lifestyle
  • food + water availability
  • predators
  • light
  • temperature
  • humidity
  • carbon dioxide conc
  • education
34
Q

Continuous variation

A

Variation where the given characteristic can take any value within a range
E.g. height and weight of plants

  • plotted as a histogram using frequency distributions
35
Q

Discontinuous variation

A

Variation where the given characteristic can take a set value- there are no in between values
E.g. blood group, sex, bacterial shape

  • plotted asa bar chart or pie chart
36
Q

Adaptation

A

A feature that enhances survival and long term reproductive success of an organism

  1. Anatomical
  2. Behavioural
  3. Physiological
37
Q

Natural selection

A

Selection by the environment of individuals that show certain favourable variations. These individuals will survive and reproduce and pass on their variations to the next generation

38
Q

Speciation

A

The formation of a new species from a pre existing one

39
Q

Anatomical adaptations

A
  • body covering
  • camouflage
  • teeth
  • mimicry

Example: marram grass
Xerophyte
- curled leaves- reduces SA and protects from wind
- hairs- trap humidity
- stomata sunken in pits- increases humidity and protects from wind
- thick waxy cuticle- reduces evaporation

40
Q

Behavioural adaptations

A
  • survival behaviours
  • courtship
  • seasonal behaviour e.g. migration or hibernation

2 categories of behavioural adaptations:
- innate: ability is inherited. Ways for organisms to survive in the environment they live in
- learned behaviour- experiential or observation of other normals

41
Q

Physiological adaptations

A

E.g. reflexes, blinking, temperature regulation

• poison production- kill prey/avoid predators
• Antibiotic production- bacteria survival mechanism to kill off others in surrounding areas
• Water holding

Analogous structure- structure that have adapted to perform the same function but have a different origin

Homologous structure- appear different but have the same underlying structure

A Level Biology (26 decks)

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