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Biology 20 AP > Ch. 4 - Population Dynamics (Excluding AP Content) > Flashcards

Ch. 4 - Population Dynamics (Excluding AP Content) Flashcards

1
Q

What is an adaptation?

A
  • A structure, behaviour, or physiological process that helps an organism survive
  • An inherited trait (or set of traits) that improve the chances of survival and reproduction of an organism
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1
Q

How do changes come about?

A

Sexual reproduction and inherited mutations.

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2
Q

What are the three categories of adaptations? Explain each.

A
  1. Structural - Structures that improve a species’s ability to survive and reproduce.
    Ex: Modification of limbs in mammals, camouflage, warning colours
  2. Behavioural - Things an organism does.
    Ex: Migration, hibernation, phototropism
  3. Physiological - Based on chemicals and internal processes.
    Ex: Venom production, pheromones (chemicals that influence behaviours of other organisms: attract mates, alarm)
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3
Q

How do adaptations develop? (2)

A

Adaptations are the result of gradual changes in the characteristics of members of a population over time.
1. Variation
2. Mutations

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4
Q

What are variations?

A

Difference, visible or otherwise, among members of a population.

These differences are created by inheriting different combinations of genetic information from parents.

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5
Q

What are mutations?

A

Random, spontaneous changes in genetic material that can be passed from parents to offspring.

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6
Q

Are mutations good? How is it passed?

A

A mutation casuing a new characteristic can be passed on to offspring only if it occurs in a new sex cell, NOT if it occurs in a body cell. In this case, a new trait is passed along and variation has occured.
- A mutation may provide an individual with an advantage or a disadvantage, or neither (neutral).
- It can happen that a mutation first offers no advantage, or even a disadvantage, and becomes favourable for oranism over time.
This more commonly happen when an organism’s environment is changing.

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7
Q

What is selective advatage?

A

Mutations that help an individual survive.

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8
Q

What is natural selection? What are the five distinct ideas in which it can occur?

A

The process by which populations change over time. Consists of several distinct ideas:
- Struggle for existence (Competition)
- Overproduction
- Variations
- Environmental changes
- Survival of the fittest

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9
Q

How does overproduction tie in to the Theory of Natural Selection?

A

More offspring is produced than can possibly survive.

Ex: Herring spawn off Alaska

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10
Q

How does struggle for existence (competition) tie in to the Theory of Natural Selection?

A

Organisms compete within and between species for limited resources because of overproduction.

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11
Q

How does variations tie in to the Theory of Natural Selection?

A

Inherited fifferences in traits occur among members of the same species.

Variation exists in all populations and the genetic differences are passed on to the next generation.

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12
Q

How does survival of the fittest tie in to the Theory of Natural Selection?

A

Surviving organisms are ones better able to compete, survive, and reproduce.

The others die without leaving offspring (natural selection).

Only those that live long enough to reproduce will pass their DNA for “desirable” traits to offspring. Less suited to die before reproducing. Population becomes more “fit’ over time.

Ex: Giraffes…short necks -> long necks
Stronger (to outrun), more food, better fighters = babies.

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13
Q

What is the impact of the enviornment on natural selection?

Define Survival of the Fittest and Selective Pressure.

A

The environment is constantly changing.

Those individuals that possess variations that allow them to tolerate, or thrive, in the environmental change, will survive and reproduce. (Survival of the Fittest)

In this way, the environment exerts selective pressure on a population.

As time passes, individuals that are selected for, continue reproducing and pass along the mutation. After time, many of the offpsring in the next generation will have this new trait, or adaptation.

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14
Q

What is artificial selection?

A

Human intervention in the breeding of plants and animals to ensure that desirable traits (like seed size, taste, coloration, etc.) are represented or magnified in successive generations.

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15
Q

Adaptation is usually a slow process, but…

A

If the species is particularly quick to reproducing, a new trait can become part of the general population very quickly, as in the case of bacteria, viruses, and insects.

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16
Q

Natural selection does not describe changes happening to individuals. Explain.

A

Individuals do not change during their lifetimes.
Species change over several generations.

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17
Q

How do new traits appear? (2)

A

Mutation
- in trait in DNA copying
- can be good or bad
Sexual reproduction produces new combinations (variation)

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18
Q

How did “the ancients” develop a theory to explain change?

A
  • Greek philosphers, like Plato and Aritstotle, over 2000 years ago believed that all life existed in a perfect and unchanging form.
  • Very conviniently fits with Judeo-Christian philosophy of creation and the Great Chain of Being
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19
Q

How did Comte de Buffon develop a theory to explain change?

A

(1749 Histoire Naturelle)
- The first to challenge the belief that species are unchanging (French naturalist)
- In 1789, published Histoire Naturelle, in which he noted to similarities between humans and apes and speculated that they may have a common ancestor
- He also went on to suggest that the Earth was much older than the 6000 years it was believed in the bible

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20
Q

How did Georges Cuvier develop a theory to explain change?

A

(Early 1800s)
- French nautralist developed the science of paleontology, using fossils to study ancient life
- Was the first to establish extinction as fact
- Identified a particular fossil tooth as a mastedon, not elephant

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21
Q

What did Cuvier examine? What theory did he propose as a result?

A

As he examined layers of rock, or strata, he noted several important things:
- Each stratum has a unique of fossil species
- The deeper he looked, the more dissimilar the species were from current life forms
- As he worked from one layer to the next, found that new species would appear, others disappear and become extinct

Proposed catastrophism: that over the course of history, many destructive natural events such as floods or volcanic eruptions (which he called revolutions) may have killed numerous species each time.

Ex: KT extinction

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22
Q

How did Thomas Malthus develop a theory to explain change?

A

(1798, “Essay on the Principles of Population”)
- Malthus lived around the same time as Cuvier, but is traditionally known as an economist, not a biologist
- Wrote an essay, that Charles Darwin studied. Argued that populations produce more offspring than their environments (food supply) could support and were reduced by starvation (competition).

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23
Q

How did Charles Lyell develop a theory to explain change?

A
  • Scottish geologist that countered Cuvier’s Theory of Revolutions
  • Proposed gradualism: that geological events are slow and continuous and can result in substantial changes over time
  • Concluded this meant the Earth wasn’t just older than 6000 years, it was ancient.
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24
Q

Between the geological theories, which idea is used today?

A

Catastrophism: the idea that the Earth ahs been subject to sudden, violent events that have been large enough to have worldwide effects (asteroid, volcano).
Gradualism/Uniformitarianism: slow/gradual/consistent processes are what have shaped the Earth’s surface (erosion). All proccesses have been occuring as they are. Requiring long periods of time.

These ideas are now combined.

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25
Q

What is the transmutation of species, and which scientists argued for and against?

A

Species were not fixed as they are, but could change over time.

Buffon and Lamarack believed the transmutation of species.
Cuvier and Lyell believed that species were unchangeable, don’t evolve, and die

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26
Q

How did Jean-Baptiste Lamarck develop a theory to explain change?

A
  • Compared current species with fossil forms and believed in a line of descent where each progressive ancient life form was more complex and closer to perfection than the last and they eventually led to the modern species.
  • Manking was at the top of the evolutionary ladder, and every less complex species was on its way to becoming a more complex species (eventually man).
  • Believed that every creature possesed “the universal creative principle” which was the will to evolve into man.
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27
Q

What is the Inheritance of Acquired Characteristics? Who believed in it? What are the two main ideas?

A

Lamarck also believed in this idea, where traits that an individual acquired during its life would be passed along to its offspring. But, by the end of the 1800s, with a greater understanding of cells, genes, heredity, Lamarack’s mechanism for inheritance was rejected.

2 main ideas:
- Law of Use and Disuse
- Acquired characteristics are inherited

28
Q

What is the Law of Use and Disuse in the “Inheritance of Acquired Characteristics”?

A

Organisms can change their body features during their lifetimes to satisfy their needs.

Ex: Giraffes are able to stretch their necks to reach leaves and this trait is passed on to their offspring.

29
Q

What is “acquired charactierstics inherited” theory in the “Inheritance of Acquired Characteristics”?

A

Characteristics changed ACQUIRED during the lifetime according to the Law of Use and Disuse of an individual can be passed on to offspring.

This is false.

30
Q

Although Lamarck had a faulty conclusion, he provided what hypothesis?

A

An organisms’s adaptations to the envronment resulted in characteristics that could be inherited by offspring.

31
Q

At the time, most people believed that species did not change, so what did Lamarck’s theory provide?

A

Scientists with anotehr way of looking at life.

32
Q

What did Charles Darwin do?

A

(1831, The Voyage of the Beagle)
- Made observations of wildlife and geography of various countries and recorded differences and similarities from place to place
- Published The Voyage of the Beagle upon returning home
- Began to specualte that one species could turn into another

(- But could now prove how variations in a trait originate)

33
Q

What did Alfred Russell Wallace do?

A
  • Naturalist and specimen collector in Brazil and Malaysia
  • speculated that the mechanism that drove the transmutation of species was natural selection.
34
Q

Both Darwin and Walalce came to similar conclusions concerning how species changed over time.
They both used ideas and evidence gathered by other scientists, such as? (2)
What diid they conclude?

A
  • Lamarck’s idea of inheritance
  • Malthus, who proposed that populations produced many more offspring than their environment could support and were eventually reduced by starvation or disease

Those that survived to reproduce must have a variation, an adaptation, that makes them more fit for the environment. In this way, competition among individuals selects for some individuals who are allowed to pass on the adapatation and against others.

Darwin called this natural selection.

35
Q

What were Darwin’s two main ideas in Origin?

A
  1. Present forms of life have arisen by descent and modification from an ancestral species
  2. The mechanism for modification is natural selection working for a long period of time
36
Q

What is evolution? What does it result in?

A

The process by which populations of living things change over a series of generations. The cumulative changes in characteristics of a population in successive generations.

Evolution results in diversity.

37
Q

What are the four direct pieces of evidence for evolution?

A

Fossils:
- Paleontology
- Radioactive Dating
- Fossil records
- Transitional fossils

38
Q

What is paleontology?

A

The study of fossils, which are the reamins, impressions, and traces of organisms from past geological ages.

39
Q

What is radioactive dating?

A

Attempts to estimate the age of rocks based on the decay of radioactive isotopes.

The relative quantities of isotopes are measured, nad calculations are based on “normal” amounts of these isotopes.

40
Q

What are fossil records?

A

Show an increase in complexity of orrganisms over time.

More recent fossils show more complex organisms.

41
Q

What are transitional fossils?

A

New discoveries of fossils are called this, that help fill in the gaps in the fossil record.

42
Q

What are the five pieces of indirect evidence for evolution?

A
  1. Embryology
  2. Morphology
    a) Homologous structures
    b) Analogous structures
  3. Vesligial structures
  4. Molecular biology
  5. Biogeography
43
Q

What is embryology?

A

The study of organisms in the early stages of development.
- Similariteis in embryos suggest a common ancestory
- All embryos (from worms to humans) go through very similar stages

44
Q

What is morpology (anatomy) and the two types?

A

Study of structures.
1. Homologous
2. Analogous

45
Q

What are homologous structures?

A
  • Structures that originate from the same soruce, but develop differently
  • Have common origins in the embryo (eg. gill slits, forelimbs of vertebrates)

Same structure, different function

46
Q

What are analogous sturctures?

A
  • Similar functional structures, but develop from different embryological sturctures
  • These organisms DON’T descent from a common ancestor

Same function, different structure

Ex: Wings

47
Q

What are vestigial sturctures?

A
  • Structures present in organisms that have no present day functions
  • May be “left over” from previous evolutionary cycles

Ex: Pelvis, leg bones in whalesW

48
Q

What is molecular biology/biochemistry?

A

Recent advances in DNA profiling and protein sequencing has allowed us to study the similarities in common molecules.

SIMILARITIES IN COMMON MOLECULES.

Ex: humans have same amount of amino acids with chimpanzees

49
Q

What is biogeography?

A

Study of geographical distrubution of plants and animals.
- Wegener’s “Pangaea” supercontinent theory
- Climate and other environmental factors affect distribution patterns of organisms over the “short term” (1000s of years)
- Changes in the position of continents (continental dift) occur over longer periods of time (millions of yrs)

50
Q

What does biogeography explain in differences?

A

Differences in the distribution of reptiles and amphibians compared to mammals are explained by the super continent theory:
- Animals that evolved before before the break up (reptiles and amphibians) are widely distributed
- Those that evolved after the breakup (mammals) are more limited in distrubution

51
Q

What are species?

A

A group of individuals capable of interbreeding and producing fertile offspring.w

52
Q

What is microevolution?

A

Is the changing of an organisms (population of organisms) over time WITHOUT a change in species.
Species does not change.

Ex: Antibiotic resistance

53
Q

What is macroevolution? What causes it and what does it cause.

A
  • Species differences becomes so great that they are no longer abel or no longer interested in interbreeding.
  • Geographic isolation often is the cause

Ex: Human evolution—a controversial topic
Evidence from Africa/Indonesia -> Homo erectus

Results in speciation.

54
Q

What is speciation? What are the two forms it may take?

A

The formation of new species, may result from the accumulation of changes in a population over time.

May take the forms of transformation or divergence.

55
Q

What is transformation?

A

Evolution of one species into another as a result of mutations and adaptation to changing environmental conditions.

Species A -> Species B

56
Q

What is divergence?

A

One or more species arise from a parent species. (because of variations)

Species A -> Species B
|
v
Species C

57
Q

What do both transformation and divergence come from?

A

Natural selection.

58
Q

Which form of speciation increases biodiversity?

A

Divergence, because it increases the number of species.

59
Q

What has to occur for speciation to occur? What are the two key things?

A

Populations must be prevented from interbreeding.
- Geographical barriers
- Biological barriers

60
Q

What are geographical barriers?

A

Physical barriers that keep populations apart.

Ex: Isthumus of Panama

61
Q

What are biological barriers?

A

Barriers that prevent populations that are not geogrphically seperated from reproducing.

Ex: Male golden orb spider and its female

Thsee barriers may be behavioural or physical, as well, there are both premating and post mating mechanisms that provide biological barriers.

62
Q

What is convergent evolution?

A

Very different species may also develop similar adaptations due to simialr needs in their environment.

E.g. squid, human eye

63
Q

What is adaptive radiation/divergence? What causes it?

A

Sudden diversification of a common ancestral species into a variety of species.

This process is usally associated with the introduction of a species to a new environment.
e.g. Galapagos finches

B/c of different environmental needs

64
Q

What is gradualism with regards to the pace of evolution?

A

Gradual changes occured in a steady, linear way over time.

65
Q

What is punctuated equilibirum with regards to the pace of evolution?

A

There were long peroids of equilibirum, interrupted by sudden periods of speciation.

According to this theory, species undergo most of their morphological changes when they first diverge from their parent species.

66
Q

Summarize the Theory of Evolution by Natural Selection. (4)

A
  1. Life forms have developed from ancestral species.
  2. All living things are related to one another by varying degrees through common descent.
  3. All living things on Earth have a common origin (share a common ancestor).
  4. The mecahnism by which one species evolved into another species invovles random heritable genetic mutations. Some mutations result in survival advantage for individuals; if so, more likely to survive and pass mutation to offspring. Eventually, the successful mutation increases population, casuing populatuion as a whole to start to change.
67
Q

What is phylogeny?

A

Study of relationships among different groups of organisms and their evolutionary development.

Diagrams respresent evolutionary relationships.

Biology 20 AP (14 decks)

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