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Life Science, T3 > Evolution > Flashcards

Evolution Flashcards

(56 cards)

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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

24
Q

Artificial Selection

Study These Flashcards
A

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

25
Artificial Selection characteristics
* Humans have selective force * Selection in response to satisfy human needs *Involve 1/more species (cross breeding)
26
Natural Selection
*Environment /nature as selective force * Selection in response to suitability to environment *Occurs within species
27
Allopatric speciation
Species diverge /split due to a geological barrier
28
How speciation occurs
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
Isolation mechanisms that keep species Seperate
*Breeding at different times * Species - specific courtship behavior * Adaptation to different pollinators * Infertile offspring *Prevention of offspring
30
Phylogenetic Trees
Diagramatic representation of evolutionary relationship between species
31
Anatomical differences between apes & humans
1. Bipedalism 2. Brain size 3. Palate size 4. Prognathous 5. Cranial Ridges 6. Zygomatic Arch 7. Dentition 8. Brow Ridges
32
Bipedalism
*Spine Gorilla: c shaped spine Human: S curve shape *Pelvic Girdle : Human : Short & wide Gorilla : long & narrow
33
Brain Size
Human: bigger cranium = bigger brain to body size
34
Lines of evidence used for common ancestor of all hominids
1) Fossil evidence (transitional species) 2) Generic evidence (mtDNA) 3) Cultural evidence (tool making)
35
Transitional species
Shows intermediate characteristics between 2 species : Ardipithecus Australopithecus Homo
36
Important fossil sites in Africa
Cradle of Human kind Sterkfontein SwartKrans Kromdraai Plovers lake Gladysvale
37
Homonid
Group consisting of modern & extinct Great Apes
38
Hominin
Group consisting of modern humans, extinct human species & all our immediate ancestors including members of genera
39
Ardipithecus ramidus
Existed: 5-4 mya Fossil site: North - East Ethiopia Discovered by: Tim White Distinctive characteristics : heavy broe ridged, very prognathous
40
Australopithecus afarensis (Lucy)
4-2.7 mya Ethopia, Kenya, Tanzania Donal Johanson Large & pointed canines, long arms, no cranial Ridges, 375-550ml brain
41
Australopithecus africans
3-2 mya Taung, Sterkfontein Raymond Dart 428-635 ml, large canines, prognathous, brow Ridges, ni cranial ridge
42
Australopithecus sediba (Karabo)
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
Australopithecus anamensis
4-3 mya M Leaky Kenya 370 cm3 Regular bipedal walking Long arms & wrist for climbing
44
Homo habilis (handy man)
2.2 - 1.6 mya Tanzania Louis & Mary Leakey 650 ml Small canines Oess prognathous Less pronounced brow Ridges No cranial Ridges
45
Homo erectus
2-0.4 mya Java in Indonesia then Swartkrans Eugene Dubois 900 ml Prognathous Cranial ridges Short canines Longer legs than arms
46
Homo naledi (star)
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
Homo sapiens
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
Pelvic girdle difference
Humans: short, wide pelvis Apes: long, narrow pelvis
49
Foramen magnum
Apes: in backward position Human: in a forward position
50
Similarities between humans & apes
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
Natural selection & artificial different
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
Population
Group of organisms of the same species that live together in a defined area at a given time.
53
Biological species
Group of organisms that have similar characteristics & can interbreed to produce fertile offspring
54
LaMarcks & Darwinism difference
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
Reproductive isolation
Mechanisms that isolate the gene pool of a species resulting in formation of new species
56
Reproductive isolation strategies
Specific courtship behavior Infertile offspring Prevention of fertilisation (incorrect size if genitalia)

Life Science, T3 (3 decks)

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