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Life Science, T3 > Evolution > Flashcards

Evolution Flashcards

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Biology 101 flashcards
1
Q

Biological Evolution

A

Changes that life forms have undergone over long periods of time

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2
Q

Evidence of Evolution

A

1) fossils
2) Biogeography
3) Descent with modification
4) Genetic evidence

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3
Q

Fossils

A

Intermediate organisms that have been discovered and probide evidence of life forms that existed in the past

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4
Q

Reasons for gaps in fossil records

A

Not all fossils that existed in earth have been found
Only a few ancient organisms are preserved as fossils because they need to be covered soon after death otherwise they will be decomposed as bacteria
Only organisms a solid & resistant skeleton are easily preserved

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5
Q

Descent with Modification

A

Inherited change in a population of organisms through time leading to appearance of new forms
Use of comparative Anatomy

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6
Q

What descent with Modification implies

A

All living organisms are related
All living organisms form part of tree of life
Common descent

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7
Q

Comparative Anatomy

A

Comparison of homologous structures (organs or skeletal elements of organisms that suggest connection to common ancestor by their similarities) organisms to show their similarities & differences

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8
Q

Biogeography

A

Scientific study of the geographic distribution of plant & animal life.

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9
Q

What biogeography states

A

Different but closely related species in similar biomes across the world have similar features in adapting to that biome indicating they’ve probably developed from same species

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10
Q

Genetic evidence states?

A

Ancestors are related & likely to have common ancestor if they have:
* identical DNA structures
* Similar seq. of genes
* Similar mutations (mtDNA)
* Similar portions of DNA with no function

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11
Q

Population

A

A group of organisms of the same species that lives together in a defined area at a given time

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12
Q

Biological species

A

A group of organisms that have similar characteristics & can interbreed to produce fertile offspring

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13
Q

Sources of variation

A

*Random arrangement
During M1 & M2
Allows different combination of chromosomes

  • Random fertilisation
    Different ova & sperm

*Random making
Between organisms within species

*Crossing over
In P1
New combinations of maternal & paternal genetic material in each new cell= meiosis

*Continuous & Discontinuous variation

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14
Q

Types of variation

A

Continuous
Discontinuous

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15
Q

Continuous Variation

A

No distinct category
Quantative
Line graph
Controlled by gene and environment
E.g) height, weight, heartrate

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16
Q

Discontinuous variation

A

Distinct categories
Qualitative
Bar graph
Controlled by genes
E.g) Eye colour, tongue rolling, blood group

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17
Q

Theories of Evolution creators

A

1) LaMarck
2) Charles Darwin
3) Eldredge & Gould

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18
Q

LaMarcks theories

A

1) Law of use & disuse
2) Law of inheritance of acquired characteristics

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19
Q

Law of Use & Disuse

A

Change in environment create new needs that cause organisms to modify their existing organs to meet the need.

Therefore
*Repeated use of organ= organ enlarge & be more efficient
* Disuse of organ= Degenerate

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20
Q

Law of Inheritance Acquired Characteristics

A

Modification an organism acquired during its lifetime could be passed on to offspring

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21
Q

Why LaMarcks theory is not accepted

A

Acquired characteristics are not inherited
Organisms did not evolve because they want to

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22
Q

Charles Darwin Theory (Law of Natural Selection)

A
  1. Members of same species produce large no. of offspring
  2. Offspring show great deal of variation
  3. Offspring compete for resources
  4. Only few of those offspring survive
  5. These have best adaoted characteristics
  6. Survival is a result of natural selection
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23
Q

Theory of Punctuated Equilibrium

A

.

24
Q

Artificial Selection

A

Breeding experiments to develop organisms with a selected set of desirable characteristics

25
Q

Artificial Selection characteristics

A
  • Humans have selective force
  • Selection in response to satisfy human needs
    *Involve 1/more species (cross breeding)
26
Q

Natural Selection

A

*Environment /nature as selective force
* Selection in response to suitability to environment
*Occurs within species

27
Q

Allopatric speciation

A

Species diverge /split due to a geological barrier

28
Q

How speciation occurs

A
  1. Division by geological barrier
  2. Population splits into 2 grps
  3. No gene flow between 2 groups
  4. Groups undergo natural selection independently due to different environmental conditions
  5. Each group adapts to new environment factors
  6. Develop differently : become genotypically & phenotypically different
  7. Leads to new species
  8. May prevent interbreeding /become reproductively isolated
29
Q

Isolation mechanisms that keep species Seperate

A

*Breeding at different times
* Species - specific courtship behavior
* Adaptation to different pollinators
* Infertile offspring
*Prevention of offspring

30
Q

Phylogenetic Trees

A

Diagramatic representation of evolutionary relationship between species

31
Q

Anatomical differences between apes & humans

A
  1. Bipedalism
  2. Brain size
  3. Palate size
  4. Prognathous
  5. Cranial Ridges
  6. Zygomatic Arch
  7. Dentition
  8. Brow Ridges
32
Q

Bipedalism

A

*Spine
Gorilla: c shaped spine
Human: S curve shape

*Pelvic Girdle :
Human : Short & wide
Gorilla : long & narrow

33
Q

Brain Size

A

Human: bigger cranium = bigger brain to body size

34
Q

Lines of evidence used for common ancestor of all hominids

A

1) Fossil evidence (transitional species)
2) Generic evidence (mtDNA)
3) Cultural evidence (tool making)

35
Q

Transitional species

A

Shows intermediate characteristics between 2 species :
Ardipithecus
Australopithecus
Homo

36
Q

Important fossil sites in Africa

A

Cradle of Human kind
Sterkfontein
SwartKrans
Kromdraai
Plovers lake
Gladysvale

37
Q

Homonid

A

Group consisting of modern & extinct Great Apes

38
Q

Hominin

A

Group consisting of modern humans, extinct human species & all our immediate ancestors including members of genera

39
Q

Ardipithecus ramidus

A

Existed: 5-4 mya
Fossil site: North - East Ethiopia
Discovered by: Tim White
Distinctive characteristics : heavy broe ridged, very prognathous

40
Q

Australopithecus afarensis (Lucy)

A

4-2.7 mya
Ethopia, Kenya, Tanzania
Donal Johanson
Large & pointed canines, long arms, no cranial Ridges, 375-550ml brain

41
Q

Australopithecus africans

A

3-2 mya
Taung, Sterkfontein
Raymond Dart
428-635 ml, large canines, prognathous, brow Ridges, ni cranial ridge

42
Q

Australopithecus sediba (Karabo)

A

1.9- 1.8 mya
Malapa Cave in Cradle of Humankind
Lee Burger
420 ml
Les prognathous
Large teeth
Long arms
No cranial Ridges

43
Q

Australopithecus anamensis

A

4-3 mya
M Leaky
Kenya
370 cm3
Regular bipedal walking
Long arms & wrist for climbing

44
Q

Homo habilis (handy man)

A

2.2 - 1.6 mya
Tanzania
Louis & Mary Leakey
650 ml
Small canines
Oess prognathous
Less pronounced brow Ridges
No cranial Ridges

45
Q

Homo erectus

A

2-0.4 mya
Java in Indonesia then Swartkrans
Eugene Dubois
900 ml
Prognathous
Cranial ridges
Short canines
Longer legs than arms

46
Q

Homo naledi (star)

A

0.4- 0.2 mya
Cradle of Human kind, rising star cave
Prof Lee Burger
460-610 cm3
Slender body, wide hips
Long curved fingers
Human like feet & hands
Prognathous

47
Q

Homo sapiens

A

0.2 mya - now
Makapansgat in Limpopo
Border Cave in KZN
Blombos Cave in Western Cape
Tim White
1200-1800 ml
Small teeth
No brow Ridges
Short arms.

48
Q

Pelvic girdle difference

A

Humans: short, wide pelvis
Apes: long, narrow pelvis

49
Q

Foramen magnum

A

Apes: in backward position
Human: in a forward position

50
Q

Similarities between humans & apes

A

Large brain
Eyes in front
Freely rotating arms
Long upper arms
Rotation around elbow joints
Bare fingertips /nails not claws
Opposable thumbs
Upright posture

51
Q

Natural selection & artificial different

A

NS has nature as selective force but AS has humans as selective force
NS has selection in response to suitability ti environment but AS gas selection in response to satisfying human needs
NS occurs within a species but AS may involve 1+ species (cross breeding)

52
Q

Population

A

Group of organisms of the same species that live together in a defined area at a given time.

53
Q

Biological species

A

Group of organisms that have similar characteristics & can interbreed to produce fertile offspring

54
Q

LaMarcks & Darwinism difference

A

Darwin offspring inherit variation but LaMarcks variation of offspring brought abt individuals changing
Darwin, environmental factors working randomly but LaMarcks as individuals wanting to change
Darwin has natural selection but LaMarcks change because of adaptation to environment
Darwin population as a whole change but LaMarcks individuals in population change

55
Q

Reproductive isolation

A

Mechanisms that isolate the gene pool of a species resulting in formation of new species

56
Q

Reproductive isolation strategies

A

Specific courtship behavior
Infertile offspring
Prevention of fertilisation (incorrect size if genitalia)

Life Science, T3 (3 decks)

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