Evolution Flashcards
1
Q
Definitions;
- Anthropology
- Biological anthropology
- Primate
A
- Anthropology: The study of humankind
- Biological anthropology: The study of humans as biological organisms, considered in an evolutionary framework
- Primate: member of the mammalian order of Primates; includes prosimians, monkeys, apes & humans
- defined by a mix of anatomical and beh. traits/characteristics
2
Q
Definitions;
- Evolution
- Genotype
- Phenotype
A
- Evolution: a change in the frequency of a gene or a trait in a population over multiple generations
- Genotype: the genetic makeup of an individual (genetic traits that are within genome)
- Phenotype: the observable or measurable feature feature of an organism which is under genetic control
- can be anatomical, biochemical or behavioural
3
Q
Evolution as a theory (4 reasons)
A
Is a theory because;
- it is a statement of well supported laws, principles or causes of something known or observed
- we can make predictions and testable hypothesis
- we can make direct observations or events or objects
- specific hypotheses are under constant modification, testing and re-evaluation
4
Q
- Biological evolution
- 2 important points in regards to evolution
- Adaptation
A
- Biological evolution: change in population or species over time
- Important points;
1. Living things descended from a common ancestor and thus have common chemistry
2. Living things adapt to their environment - Adaptation: a trait that increases the reproductive success of an organism, produced by natural selection in the context of a particular environment.
- humans are the product of adaption
5
Q
3 vital elements for natural selection
A
- Variation: there must be physical variations that can be passed from generation to generation
- Competition: There must be competition for limited resources (food, shelter, mates) and those better adapted will survive and reproduce
- Adaptation: subsequent generations will see an increase in individuals w/ same adaptations, as long as the enviromnet remains unchanged
6
Q
Artificial selection
A
- carried out by humans for thousands of years
- desirable trait is bred for
- i.e. wolves into domesticated dogs
- Chinese cabbage,, brussel sprouts & kohlrabi all derived from single species (Brassica oleracea)
7
Q
Evidence to support theory of evolution by common descent (4)
A
- Fossil record
- Biogeographical evidence
- Anatomical evidence
- Biochemical evidence
8
Q
Evidence for evolution;
Fossils
- what they are
- paleontology
- transitional fossil
- what the fossil record tells us
A
- are traces of past life (can be trails, footprints, burrows, worm casts, coprolites (fossilized poo), plant impressions, insects trapped in amber).
- Paleontology = method that allows us to trace the descent of a particular group
- Transitional fossil: fossils that have characteristics of 2 different groups
- fossil record tells us that life progressed from simple to more complex
9
Q
Evidence for evolution;
Biogeographical evidence
A
- Is the study of the distribution of plants and animals throughout the world
- supports the hypothesis that organisms originate in one locale and then may spread out
- Diff. life forms expected whenever geography separates them
- Islands have many unique life forms because of geographic isolation
10
Q
Evidence of Evolution;
-Anatomical Evidence
Homologous structures
- analogous structures
- Vestigial structures
A
- common descent hypothesis offers explanation for anatomical similarities among living organisms.
- Homologous structures: structures anatomically similar that are inherited by a common ancestor
- i.e. vertebrate forelimbs
- Analogous structures: structures that serve the same function but do not share common ancestry (therefore not constructed the same
- Vestigial Structures: anatomical features fully developed in one group that are reduced and may have no function in another group
e. g. humans have appendix and tail bone - coccyx
11
Q
Pentadactyl limb
A
- Modified from the terrestrial vertebrate forelimb for various functions/use
- similar layout in alive and extinct tetrapods
- distal ends may be modified according to the environment they live in
12
Q
Evidence from embryology
A
-Early in embryo development; many different species look very similar
13
Q
Evidence of Evolution;
Biochemical evidence
A
- Almost all living things use same biochemicals (i.e. DNA and ATP)
- use same triplet genetic code and use same 20 a.a.
- living things also share many of the same genes
14
Q
Taxonomy
- What it is
- Common name
A
- Science of classification by hierarchy
- Scientific taxonomy is testable classification of life forms
- common name often different in different countries
15
Q
Linnean Classification
*starting with Domain
A
- Domain/Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
- go from general to specific
16
Q
Binomial Classification
A
- Each species receives double name in Latin
- Genus & species
17
Q
The 3 domains of life
A
- Bacteria
- Archaea
- Eukarya
18
Q
Kingdoms
A
- 5 kingdom system standard for some years -> largely based on nutrition
- monera and protista (single celled or simple cellular colonies)
- Fungi
- Plantae
- Animalia
19
Q
Kingdom animalia - 4 features
A
- Eukaryotic: possess nuclei w/ DNA arranged in chromosomes; possess organelles
- multicellular (tissue specialization)
- Heterotrophic (digest food in internal chamber)
- Lack rigid cell walls
20
Q
Phylum - Chordata
-features
A
- Share certain taxonomic features
- Notochord: a rodlike body found in all embryos serving as longitudinal support
- Hollow dorsal nerve cord (runs in line w/ notochord)
- vertebrates are a subset of phylum Chordata
21
Q
Subphylum: Vertebrata
- features
- no of species
- what all of them have
- limb numbers
A
- Animal w/ spinal column (backbone) and a cranium (brain case)
- approx 40 000 species of vertebrates in 8 classes
- Most have a spinal column made of vertebrae (shark doesnt - has cartilage)
- are all bilaterally symmetrical
- body usu. divided into a head & a trunk
- more advanced land vertebrates have a neck
- In mammals: trunk divided into thorax & abdomen
- Vertebrates never have more than two pairs of limbs
22
Q
Class - features of a class
- class human belong to
- 4 features of this class
A
-Have more characteristics in common than members of a phylum - generally more easily recognized as similar
-Humans belong to class MAMMALIA
features (4):
-Mammary glands (modified sweat glands)
-hair
-Warm blooded (endothermic) w/ 4 chambered heart
-viviparous (gives birth to live young)
23
Q
Order -> Primate
- Unique feature of primate (unusual in normal orders)
- what are they
A
- Uniquely among Mammalia, primates have no single anatomical trait that is the identifying mark of a primate and no trait that unites them
- Are generalist foragers w/ relatively large brains and intricate, complex social system
24
Q
Characteristics of Primates (6)
A
- Opposable thumb
- steroscopic vision (depth perception)
- Well-developed brain
- Reduced number of offspring w/ an increased period of parental care
- Emphasis on learned behaviour and social interactions
- long lives
25
Q
What is a Primate?
-general traits that primates generally have some or all of
A
- Primates (including fossil) have SOME or ALL of these traits;
- bony ring around eye socket or bony enclosed eye socket
- hands or feet that are constructed so they can grasp objects (exhibit prehension)
- opposable thumb
- external genitalia; 2 pectoral mammary glands
- nails on edges of digits (unguiculate)
- binocular vision
- long gestation
- slow-post natal growth compared to maternal body size
- emphasis on learned behaviour and social interactions
- large brain size relative to body size
26
Q
Family Hominidae
- when appeared -> when human group appeared
- features
A
- early hominids appeard in Miocene (approx. 20 MYA)
- 4 genera w/in
- human group (Hominins) dates back to around 5 MYA
- 4 genera w/in
- Features;
- still larger brain
- larger body size
- mostly terrestrial
- arms and pectoral girdle for suspension
- highly reduced or absent tails
- Y-5 shaped pattern on occlusal surface of molar teeth
27
Q
Genus and Species - Homo sapiens
- emergence
- name of modern humans
- subspecies?
A
- ‘wise man’ emerged approx. 200 000 years go
- modern humans classed as Homo sapiens sapiens
- various extinct subspecies such as Homo (sapiens) neanderthalensis, homo heidelbergensis
28
Q
Genus and Species of Homo sapiens
-characteristics (6)
A
- upright posture and bipedal locomotion
- larger brains
- language capabilities and symbolic thought
- the manufacture and use of complex tools
- shortened jaw & shorter digestive tract (due to development of agriculture)
29
Q
Evolutions of hominins
- what is a hominin?
- 3 major characteristics
- when first hominins fossils appeared (can give detail about which region of african (3))
- when hominids split from ape line of descent
A
-Hominins: all species of genus Homo and their close relatives
3 features;
- Bipedal
- Flatter face with more pronounced chin
- Brain size
- first hominin fossil approx 6-7 MYA
- central african fossil 7MYA (Sahelanthropus tchadensis)
- Eastern African fossil 6 MYA (Orrorin tugenensis)
- Eastern African Fossil 5.8-5.2 MYA (Ardipithecus kadabba)
*Hominins split from the ape line of descent 5-6 MYA
30
Q
Australopithecines
- when evolved & diversified
- features
- famous skeleton
-Most likely ancestral candidate for early Homo
A
- Group of hominins that evolved and diversified in Africa approx 3MYA
- Various frames (some slight others robust) w/ massive jaws for feeding on plant material
- walked upright
- limb portions apelike
- small brain
- famous skeleton named Lucy (A. afarensis)
*Australopithecus africanus (w/ large brain) is most likely ancestral candidate for early Homo
31
Q
Characteristics of Homo (3)
-2 representatives from early Homo and later Homo
A
- Brain size is 600cm^3 or greater
- evidence of tool use
- jaw and teeth resemble humans
- Early Homo representatives (Homo habilis & Homo erectus)
- Later Homo representatives (Neandertals & Cro-Magnons)
32
Q
Homo habilis
- when lived
- 4 features
A
-Lived 2.0-1.9MYA
- large brain w/ enlargd speech area (derived from skull)
- Omnivorous (hunters and gathers)
- Primitive tools
- May have had culture
33
Q
Homo erectus
- when lived
- 6 features
- where thought to have come from
A
-lived 1.9-0.3MYA
- Larger brain than H. habilis
- flat face with nose projected
- tall and stood erect
- striding gait
- Advanced tools and fire (systemic hunters)
- May have had language
- may have migrated from Africa to Europe and Asia
34
Q
Modern Humans: Replacement model
A
- AKA out of Africa Hypothesis -> is most widely accepted hypothesis
- proposes that modern humans evolved from archaic humans only in Africa
- Then, modern humans migrated to Asian & Europe where they replaced the archaic species about 100000 years BP
-waves of species that came out of Homo ergaster and differentiated into different species in different continents
35
Q
Neaderthals
- when & where discovered
- 3 features
A
- discovered in Germany 2000 years ago
- Homo sapiens have 1-4% similarity to their DNA -> suggests interbreeding
- massive brow ridges
- nose, jaws, and teeth protrude forward
- low and sloping forehead; no chin
36
Q
Cro-Magnons
- when lived
- features
A
- Lived about 40 000 - 10 000 years ago
- oldest fossils designated to Homo sapiens
- modern appearance
- advanced culture including art, tools and maybe language
- Good cooperative hunters
37
Q
Human Variation
- ethnicities
- why variations exists between populations (e.g. of it)
- Bergmann’s rule
- Allens rule
A
- Human variations b/w populations = ethnicities
- Variations evolved as adaptation to local environments
- i.e. skin colour and body shape
- Bergmann’’s rule: colder regions mean bulkier build
- Allen’s rule: colder regions mean shorter limbs, digits and ears
- i.e. skin colour and body shape
38
Q
Requirements for Bipedalism (3)
-3 times it has occurred in mammals
A
- Positioning of centre of mass over lower limbs
- Efficient maintenance of this position
- Reduction of protrusions away from centre of mass (to be more efficient)
Has only occurred 3 times in mammals; Kangaroo, Kangaroo mouse & humans
39
Q
Human Engineering -> adaptations that make us suitable for bipedal life
*bone modifications
A
- gluteus maximum v. powerful hip extensor (prevents torso from falling over)
- bowl shape, short and broad pelvis bone -> enables us to support abdominal organs
- shorter ileum (decreases centre of gravity & makes childbirth easier as pelvis rotated)
- spine has lots of ligaments attached
- curvature of spine to distribute weight appropriately
- elongation of neck of femur (import. in balance)
- femur curves in to knee (centre of gravity)
- Menisci present in knee to help weight distribution
40
Q
Human Engineering -> adaptations that make us suitable for bipedal life
*foot modifications
A
- big toe adducted to facilitate walking
- toes shorter so we don’t trip
- thickening of plantar fascia provides platform that can absorb energy and return it by giving added thrust
- arches in foot = shock absorbers
41
Q
Human Engineering -> adaptations that make us suitable for bipedal life
Cranial Modifications & Pectoral girdle
A
- Prognathism: Projection of lower jaw and facial skeleton
- Has been a decrease in the protrusion of the face (helps maintain the center of gravity
- foramen magnum more inferior to cranium
- pectoral girdle is wider laterally
- Scapula more medial (apes have lateral scapula)
42
Q
Human skeleton vs. chimpanzee skeleton (human examples) (6)
A
- Spine exits inferior to center of skull and this = midline of body
- Longer, S-shaped spine -> places trunk’s center of gravity squarely over feet
- Broader pelvis & hip joints keeps humans from swaying when walk
- Longer neck of femur in humans cause femur to angle inward at knee
- Human knee joint modified to support body’s weight (femur larger at bottom, tibia larger on top)
- Human toe not opposable - foot has arch that enables humans to walk & run long distances
43
Q
Classification of humans (domain to species)
A
Domain: Eukarya Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Family: Hominidae Genus: Homo Species: sapiens
