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Evolution of Cells > Life - patterns in evolution > Flashcards

Life - patterns in evolution Flashcards

1
Q

What does it mean to say that a species is dimorphic?

A

Females and males of the species have prominent differences in physical characteristics

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2
Q

What are cryptic species?

A

Species that are morphologically indistinguishable, yet do not inter breed

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3
Q

What is the lineage species concept

A

The idea that the history of a species can be seen as starting and ending with a speciation event (or extinction)

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4
Q

What happens, in terms of genetics, to populations that are isolated over time

A

They may acquire new fixed alleles at many different loci

Offspring between isolated groups is likely to be functionally inferior

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5
Q

What is allopatric speciation?

A

Speciation caused by geographical/physical isolation

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6
Q

What is the dominant mode of speciation in most oranisms?

A

Allopatric

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7
Q

What is sympatric speciation?

A

Reproductive isolation of populations inhabiting the same regions

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8
Q

Speciation is usually a gradual process. Give an exception

A

Polyploidy (chromosome duplication)

In only a couple of generations, complete reproductive isolation may occur

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9
Q

Give four example of prezygotic reproductive barriers

A

Mechanical isolation, temporal isolation, behavioural isolation and habitat isolation

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10
Q

What is low hybrid zygote viability?

A

Hybrid zygotes failing to develop/mature normally

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11
Q

What is low hybrid adult viability?

A

Hybrid offspring has low survivorship rate

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12
Q

What is hybrid infertility?

A

Hybrid offspring, like mules,

which are sterile

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13
Q

What is reinforcement?

A

When natural selection favours traits that strengthen prezygotic barriers, driving isolated populations apart further

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14
Q

What is speciation?

A

The process by which one species splits into two or more daughter species, which thereafter evolve as distinct lineages

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15
Q

How does the biological species concept distinguish species?

A

On the basis of reproductive isolation

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16
Q

How does the morphological species concept distinguish species?

A

On the basis of physical characteristics

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17
Q

Give 4 factors that influence rates of speciation

A

Dispersal ability, type of pollination, sexual selection and specialised diets

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18
Q

birds which are sexually dimorphic have _ rates of speciation than monomorphic species

A

Higher

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19
Q

For wind-pollinated plants, speciation rates are _ than those for animal-pollinated plants

A

Lower

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20
Q

Why can a high diversity of host plants lead to higher rates of speciation for herbivorous bugs?

A

They usually only specialise on a few closely related plants.
There are lots of opportunities for exploitation

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21
Q

Why do animals with complex sexual selection behaviours have higher speciation rates?

A

Sophisticated discrimination of partners can have a large impact on which individuals are successful

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22
Q

Why do species with lower dispersal ability have higher rates of speciation?

A

Even a a small physical barrier can have a large impact

23
Q

What is evolutionary radiation?

A

When a large number of daughter species descend from a single ancestor

24
Q

When is evolutionary radiation adpative?

A

When daughter species have a diverse array of characteristics used to exploit many different environments

25
Q

What do multicellular eukaryotes and unicellular prokaryotes have in common?

A

They use the process of glycolysis

They have plasma membranes and ribosomes

They use DNA as genetic material - transcription, translation, replication processes

26
Q

give an example of a type of universal gene

A

The genes that code for structural components of ribosomes

27
Q

Read this

A

Prokaryotic cells lack a cytoskeleton and a nucleus

28
Q

What process do prokaryotic cells use to divide?

A

Binary fission

29
Q

Many prokaryotic cells have only one main chromosome, making them _

A

Haploids

30
Q

Eukaryotic cells have a most common ancestor with _

A

Archaea

31
Q

Last common ancestor of the three domains lived

A

2 to 3 billion years ago

32
Q

The bacteria in your intestinal tract _

A

outnumber all of the humans that have ever lived

33
Q

Why are multicellular colonies of prokaryotes not considered to be a multicellular organism?

A

They are fully viable as individuals

34
Q

Prokaryotes adhere to one another after binary fission, forming associations in _

A

the form of chains

35
Q

Dental plaque is _

A

A biofilm

36
Q

What are the oldest fossils ever discovered?

A

Stromatolites - layers of fossilized biofilms

37
Q

How do microbes form biofilms?

A

They bind to a surface and then secrete a sticky polysaccharide substance which traps other cells

38
Q

The cell wall of almost all bacteria contain _

A

Peptidoglycan

39
Q

What determines whether a cell is gram-positive or gram-negative?

A

Whether or not they retain dye during the chemical treatment

40
Q

Gram-negative cells have a _ peptidoglycan layer

A

Thin

41
Q

Gram-positive cells have a _ peptidoglycan layer

A

Thick. 5 times as much

42
Q

gram- _ prokaryotes have a _ space between an inner and outer membrane

A

negative

periplasmic

43
Q

Why are cell walls a good target against pathogenic bacteria?

A

Because there is no counterpart in eukaryotes. Less collateral damage

44
Q

Give an example of bacteria communicating chemically

A

Quorum sensing - detecting population density by chemical means

45
Q

Give an example of bacteria communicating physically

A

Bioluminescence

46
Q

Prokaryotes display _ metabolic diversity than eukaryotes

A

Greater

47
Q

What is the difference in the motion of flagella between prok and euk

A

Pro have rotation around the base

Euk more of a whip like action

48
Q

What is the typic generation time scale for bacterial cells?

A

Days to hours

49
Q

What are obligate anaerobes?

A

Cells that live only through anaerobic metabolism. Molecular oxygen is poisonous to them

50
Q

Which kinds of prokaryotes perform cellular respiration?

A

Obligate aerobes and facultative anaerobes

51
Q

What are obligate aerobes?

A

Cells that cannot survive with out oxygen for extended periods. They use cellular respiration

52
Q

What are aerotolerant anaerobes?

A

Oxygen is not poisonous to these cells but they do not perform cellular respiration

53
Q

What are facultative anaerobes?

A

Cells that switch between anaerobic and aerobic modes

54
Q

What are photoautotraphs?

A

Cells that perform photosynthesis - using light as an energy and CO2 as a carbon source

Evolution of Cells (6 decks)

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