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Biology 20 > Unit B2: Mechanisms of Population Change > Flashcards

Unit B2: Mechanisms of Population Change Flashcards

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1
Q

adaptive radiation:

A

diversification of a common ancestral species into a variety of species of all which are differently adapted

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2
Q

speciation:

A

the process where new species form
- new species defined as unable to make fertile offspring with original species
- two methods

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3
Q

what are the two paces of speciation:

A

gradualism and punctuated equilibrium

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4
Q

biological barriers:

A

-factors that keep a species reproductively isolated even when they exist in the same region
-behaviour
- mating
- courtship
- pheromones
- different habitats

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5
Q

what are the two methods of speciation?

A

transformation and divergence

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6
Q

convergent evolution:

A

-different ancestors, similar selective pressures

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7
Q

what level does selective pressure act on?

A

individual

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8
Q

Lamarcks use or disuse:

A
  • Lamarck says that it is the use and disuse of traits that result in inheritance
  • traits in individuals can change over a lifetime, and these changes will be passed on to decendents
  • ex. giraffes stretching their necks
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9
Q

from molecular biology we have learned:

A

-all cells consist of membranes filled with water, genetic material, proteins, lipids, carbohydrates
- enzymes(proteins) control biochemical reactions
- proteins are synthesized from amino acids
- all cells that can replicate have DNA

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10
Q

Darwins theory of the origin of new species(speciation)

A
  • through the accumulation of inherited traits over the generations, eventually a population becomes so different that they cannot reproduce with the original population from which they came from
  • a new species then forms (speciation=creation of new species)
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11
Q

continental drift:

A

the movement of the continents relative to eachother across the ocean floor
- fossils of the same species can be found on the cpastline of neighbouring continents
- pangaea- the super continent before continental drift

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12
Q

Adaptation:

A

structures, behaviours, or physiological processes shared by all individuals in populations that help them survive
- these adaptations are a result of a gradual change in the genetic characteristics of members of a population over time
-population*
- type of trait
- if a trait helps and the organism surive=adaptation
- selectively advantageous traits that allow an organism to survive in a habitat

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13
Q

Natural selection

A

-natural selection will select a trait that increases an organisms fitness for survival
-process where the environment selects traits that allow the individual or group to survive best
- these traits are passed through reproduction

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14
Q

Darwinian explanation of evolutionary change:

A
  • all species have a variety of traits, some of which have a genetic link
    -change in species over time will occur when favoured forms provide a selective advantage over others, and these changes will be passed on to later generations
  • “descent with modification”
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15
Q

scientific theory:

A

a prediction that leads to successful predictions and explanations
-a general statement that explains and makes successful predictions about a broad range of observations
- can be repeatedly tested and corroborated

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16
Q

comparative anatomy:

A
  • One of the types of evidence for evolution
  • the study of similarities and differences in the anatomy of species
  • similarities are known as homologous structures and indicate a common ancestry
    -homologous structures and analogous structures
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17
Q

descent with modification:

A

-Darwin says that there is “descent with modification”, implying that individuals vary from one to the other, and the ones that survive can pass their traits on to the next generation

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18
Q

According to Darwin, who does natural selection act on?

A

individuals with favourable variations

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19
Q

evolution:

A

A permanent genetic change in a population
- groups of the same individual(populations evolve, not individuals)
- may not be visible(small changes)
- does not refer to changes occurring to individuals within their own lifetime

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20
Q

Darwins theory of overproduction:

A

more offspring are born than can possibly survive with the given resources

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21
Q

Lamarkian explanation of evolutionary change:

A

-results of a species changing and accumulation of the changes over a lifetime were heritable and could be passed on to their offspring
- time and favourable conditions have given rise to the diversity of organisms on the earth
-“use or disuse”

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22
Q

selective advantage:

A

characteristics that improve an organism’s CHANCE of survival, usually in a changing environment (the result of mutations)

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23
Q

example of adult features:

A

basic arm bone arrangements

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24
Q

homologous structures:

A

-different function
- form a common ancestor
- divergent evolution
- ex. bones between species are organized in the same way but used for different functions

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25
Q

what did Lamarck argue?

A

-he argued that if the environment of an organism changes, the organism will change its behaviour and adapt to fit the new environment
- use of an organ or appendage would cause growth in that structure where disuse would result in the structure shrinking or disappearing

26
Q

molecular genetics:

A

-evolutionary relationship among species(DNA)
- improvements in technology to identify molecules like DNA and protein molecules
- one of the pieces of evidence for evolutiom
-common ancestry and evolution through natural
selection

27
Q

what did darwin establish?

A

-he published “On the Origin of Species by Means of Natural Selection” in 1859
- this established the theory of natural selection as the dominant scientific explanation of diversification in nature
- it is what we use to this day

28
Q

two types of natural selection:

A

selective advantage and selective pressure

29
Q

The fossil records:

A
  • fossils are parts or impressions of an organism after it dies
    -fossils are formed when an organism is buried quickly in conditions that slow decay
  • most commonly found in sedimentary rock
  • fossils appear in chronological order in rock layers(strata) (younger ones are near the top and the oldest ones are the deepest
  • some organisms in the fossil record are no longer found today(extinction)
30
Q

What did Lamarck do?

A
  • first to publish true evolutionary ideas and to oppose the church’s teachings
  • suggested that humans evolved from a common ancestor
31
Q

What are darwins 5 main theories?

A
  1. overproduction
  2. struggle for existence(competition)
  3. variation
  4. survival of the fittest(natural selection)
  5. origin of new species(speciation)
32
Q

variation:

A
  • one of Darwins 5 major theories
  • a visible or invisible difference that helps or hinders an individual (can be neutral)
  • individual*
  • some provide a survival advantage, some a disadvantage, and some make no difference at all
33
Q

embryology:

A
  • evidence for evolution
  • study of an organisms development
    -many different organisms exhibit similar stages of embryonic development
  • suggests a common ancestor
    -embryos of more closely related organisms continue to appear similar until a later stage
    -related species would share both adult features and embryonic features
34
Q

darwins theory of variation:

A

differences exist between individuals within the same population
-only identical twins are genetically identical
-the original source of these variations are mutations to the genetic information

35
Q

divergent evolution:

A

-one ancestor, different selective pressures

36
Q

biological species:

A

a group of interbreeding individuals that produce viable offspring and are reproductively isolated from other groups

37
Q

when did darwin live?

A

1809- 1882

38
Q

what is an example of a variation?

A

blue vs brown eye colour

39
Q

convergent evolution is a part of…..

A

analogous structures

40
Q

Darwins theory of survival of the fittest(natural selection):

A

-individuals with traits that allow them to be better competitors for the limited resources are MORE LIKELY to survive AND reproduce
- these advantageous traits are then passed on to the future generations
- the non-beneficial traits are less likely to be passed on since the individuals do not survive and reproduce

41
Q

what is the inheritance of acquired characteristics(Lamarck)

A

stated that characteristics, (such as large muscles) that were acquired during an organism’s lifetime could be passed on to its offspring

42
Q

how does speciation occur?

A

-populations must be prevented from breeding
- populations must become isolated from one another through geographical or biological barriers

43
Q

geographical barriers:

A
  • keep populations physically separated
    -mountains
    • rivers
    • lava flow
  • does not have to be maintained forever
44
Q

analogous structures:

A

-organisms have similar function
- adaptations evolved in similar environmental conditions/selective pressures
- convergent evolution

45
Q

Darwin’s theory of struggle for existence(competition):

A

because there is an excess number of offspring, competition results in the limited resources that are available

46
Q

divergence:

A

a parent evolves into more than one other species
ex. ancestral horse turn into modern day donkeys, zebras, and horses

one of the 2 methods of speciation

47
Q

what is transformation:

A

-gradualism
-steps of gradualism

48
Q

punctuated equilibrium:

A

theorizes that evolutionary history consists of long periods of equilibrium where there is little change, and then interrupted by rapid species divergence

49
Q

example of embryonic features:

A

presences of paired pouches in throat

50
Q

how are genetic variations created?

A

genetic variations are created through sexual reproduction or mutations

51
Q

when did Lamarck live:

A

1744-1829

52
Q

what did Lamarck believe/say?

A
  • species could mutate and change over time(mainly from fossil evidence)
    -believes in the inheritance of acquired characteristics
  • believed that if structures/organs remain inactive for some time, they will eventually disappear
53
Q

mutations:

A
  • changes in the DNA of an organisms
  • mutations can occur with DNA copying errors
  • means to create new genes
  • most of the time they are neutral
54
Q

biogeography:

A
  • another theory of evolution
  • -each plant and animal species originated only once and has a centre of origin
  • regions that have been separated from the rest of the world for a long time often have large number of unique species that are found nowhere else
  • geographically close environments are more likely to be populated by related species than locations that are geographically separated
    -continental drift
55
Q

divergent evolution is a part of…..

A

homologous structures

56
Q

what is analogous structures a result of:

A

organisms adapting their physical structures independently to a similar environment

57
Q

evidence for evolution according to darwins works was found through:

A

-the fossil records
-comparative anatomy
- embryology
- biogeography
- molecular genetics

58
Q

transformation:

A

a new species gradually develops as a result of mutation and adaptation to changing environmental conditions
(original species no longer exists)

59
Q

sexual reproduction:

A

-mixing of genetic material from both parents
- does not create new genes

60
Q

selective pressure:

A

ENVIRONMENTAL conditions that help certain characteristics of individuals and hinder others

61
Q

gradualism:

A

theorizes that gradual change occurs in a steady, linear way over time
(darwins belief)

62
Q

evolution acts on what level?

A

population

Biology 20 (5 decks)

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