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Evolution by Natural Selection
The process by which organisms with advantageous traits survive and reproduce more successfully than those without, leading to changes in the genetic makeup of a population over time.
4 Principles of Darwin’s Theory of Natural Selection
Overproduction: All species produce more offspring than the resources can support
Variation: There is natural variation btwn individuals of a species
Natural Selection: Individuals w advantageous genotypes will be more likely to survive & produce offspring
Inheritance: Over subsequent generations, the frequency of advantageous genotype increases, leading eventually to evolution of species
Factors that contribute to potentially beneficial variation
Recombination
Independent assortment & segregation
Genetic mutations
Lamarck's Theory of Evolution
Lamarck's Theory of Evolution: The idea that variation is acquired from one generation to the next through the use or disuse of certain traits, leading to the gradual transformation of species over time.
Darwin's Theory of Evolution
Theory that explains how species evolve over time through natural selection. Organisms with advantageous traits are more likely to survive and reproduce, passing on those traits to their offspring. This leads to the development of new species over millions of years.
3 Basic Ingredients of Life
Source of energy (sun or thermal vents)
Carbon source
Liquid water
What is Spontaneous Generation?
Spontaneous Generation is the belief that living organisms can arise from non-living matter through natural processes.
What are the three processes needed for the origin of life?
The three processes needed for the origin of life are chemical evolution (formation of simple organic molecules), formation of self-replicating polymers, and the development of a cell membrane.
What were the conditions of the primordial sea?
High volcanic activity
High UV radiation (thin atmosphere)
Lightning
Water vapour, methane, ammonia, hydrogen
What were the life-giving elements of undersea thermal vents?
Gases
Energy (heat)
A possible source of catalyst (metal sulfides) for life to develop
What was Panspermia?
A theory arguing that life originated in space, and that organic molecules (amino acids and water) were continuously distributed on early Earth via heavy meteorite bombardment (approx. 4000 million years ago).
What are proto-cells and 3 essential characteristics?
The first/primordial cell. Essential characteristics include:
A membrane separating the internal environment from the external environment
Storage capacity for specific biological molecules
The ability to replicate
What properties suggest that the first cells formed from RNA molecules?
RNA can self-replicate
RNA is able to store information in a sequence of four nucleotides (similar to DNA)
Short sequences of RNA have been able to duplicate other molecules of RNA accurately
RNA can act as a catalyst
Modern cells use RNA catalysts (ribosomes) to remove introns from mRNA and to help synthesise new RNA molecules
In ribosomes, rRNA is found in the catalytic site and plays a role in peptide bond formation
In what way has RNA been superseded by DNA and protein?
DNA has greater chemical stability, and thus has superior (data) storage capacities
Protein, through its greater variability (20 amino acids vs. 4 nucleotides) has taken over as the catalytic form
Microbial mats such as stromatolites are….
…. multilayered sheets formed by microorganisms such as archaea and bacteria.
Evidence of these mats date to at least 3.5 billion years old
Evidence suggests that life could be even older (approx. 4 billion years old)
Presence of ancient stromatolites proves that Earth’s environment contained oxygen very early on. The oxygen was derived from the photosynthetic activity of cyanobacteria
What was the process of oxygen enrichment between 2.5-3.0 billion years ago?
Evidence that indicates oxygen-producing bacteria evolved, eventually becoming photosynthesis. This helped transform the planet from an environment lacking in free oxygen, to one of continuously increasing levels.
Led to key events such as the production of oxidised compounds, the evolution of aerobic organisms, and the changing of Earth’s atmosphere
Subsequent formation of an ozone layer restricted UV radiation, allowing the proliferation of a wider range of life forms
How did the eukaryotic cell evolve?
Eukaryotic cells first appeared approx. 2 billion years ago.
Evolved from large prokaryotic cells that ingested other prokaryotes, through phagocytosis.
A symbiotic relationship was formed, enabling the engulfed prokaryotic cell to continue functioning.
Define endosymbiont.
Endosymbiont = a cell which lives inside another cell with mutual benefit.
Eukaryotic cells believed to have evolved from early prokaryotes that engulfed other cells by phagocytosis
Engulfed cell remained undigested as it contributed new functionality to the engulfing cell (ie. photosynthesis)
Over generations, the engulfed cell lost some of its independent utility, becoming a supplemental organelle
What is the suggested evidence for endosymbiosis?
Double membrane
Antibiotic susceptibility
Division as a mode of replication
Presence and structural composition of DNA
Ribosome size Examples of organelles that present these characteristics include mitochondria and chloroplasts.
Define fossil.
Fossil = the preserved remains or traces of any organism from the remote past
What are the two types of fossil evidence?
Direct (body fossils) = bones, teeth, shells, leaves, etc.
Indirect (trace fossils) = footprints, tooth marks, tracks, burrows, etc.
What is the fossil record? What does it show?
Fossil record = the totality of fossils, both discovered and undiscovered
Shows that changes have occurred in the features of living organisms (evolution)
Shows new species emerging (divergence and speciation) and extinctions
Supports evolution as it demonstrates a change in an organism’s characteristics from an ancestral form
What is the Law of Fossil Succession?
Law of Fossil Succession (LFS) = The chronological sequence of complexity by which characteristics appear to develop
Fossils can be dated by determining the age of the rock layer (strata) in which the fossil is found
Sedimentary rock layers develop in a chronological order, such that lower layers are older and new strata form on top
Each strata represents a variable length of time that is classified according to a geological time scale (eons, eras, periods, etc.)
LFS suggests that newer species likely evolved as a result of changes to ancestral species
Occurrence of transitional fossils demonstrate the intermediary forms that occurred over the evolutionary pathway taken within a single genus
Why is the fossil record incomplete?
Fossilisation requires an unusually specific combination of circumstances:
Rapid burial (high pressure)
Lack of oxygen (no decomposition by bacteria)
Preservation of remains (not removed or consumed by scavengers) These conditions aren’t common, so many gaps exist in the fossil record. Also, usually only the hard parts of an organism are preserved, and often only fragments of fossilised remains are discovered.
What is biogeography?
Biogeography describes the distribution of lifeforms over geographical areas, both in past and present times.
Provides evidence for evolution because it suggests that closely distributed species share common lineage
If speciation was random, distribution of structurally similar species would be expected to be scattered
What is the basic principle of biogeography?
Each plant and animal species originated only once. The place where this occurred is the centre of origin.
All species will have their own centre of origin.
Related species are found in close proximity (supporting concept of speciation via gradual divergence)
Fossils found in particular regions tend to closely resemble the modern organisms of the region
Continental drift explains exceptions to the correlation between biogeographical distribution and common ancestry
Regions that have been separated from the rest of the world for a long time (ie. Madagascar, Australia, NZ), often have distinctive biota comprising a large number of endemic species (species found nowhere else)
What is the purpose of comparative anatomy?
Comparative anatomy of groups of organisms may show certain structural features that are similar, implying common ancestry.
What are homologous structures, and their relevance in comparative anatomy?
Homologous structures = anatomical features that are similar in basic structure, despite being used in different manners
Two species are more closely related if there are greater similarities between their homologous structures
Homologous structures illustrate adaptive radiation, whereby several new species rapidly diversify from an ancestral source, with each new species adapted to utilise a specific unoccupied niche
Tetrapods (organisms with 4 limbs) all have very similar bone structures in their limbs (pentadactyl), despite different functions for the limbs
This indicates a common ancestry, followed by evolutionary changes and natural selection
What are analogous structures?
Analogous structures = anatomical features of different species that have a similar function, but different structure and origin.
Usually arise via convergent evolution due to similar niches or selection pressures
Butterfly wing vs. bird wing
Mammal eye vs. octopus eye
What are vestigial structures?
Vestigial structures = small remnants of organs which were previously useful in a species’ evolutionary history.
Vestigial wings in kiwis
Vestigial pelvic bone in snakes and whales
Vestigial appendix in humans These structures generally don’t disappear completely, as the selection pressure for that to occur isn’t present → the genes for their presence are still active, or they still have a minor function
Give 3 examples of biomechanical evidence that can be used to show common ancestry and evolutionary change.
Proteins
DNA
Homeobox (Hox) genes
How can proteins provide evidence of evolutionary change?
Amino acid sequences are determined by inherited genes and differences are due to the accumulation of mutations
Degree of similarity of these proteins is determined by the number of mutations that have occurred
Distantly related species have had more time for differences to accumulate
How can DNA provide evidence of evolutionary change?
Species thought to be closely related on the basis of other evidence, usually have a greater percentage of DNA sequences in common
ie. Humans and chimpanzees have 97.6% similarity in DNA sequence, and are very closely related
What is the process and purpose of DNA hybridisation?
In DNA hybridisation, DNA strands can be separated with sufficient heat, and will reform (reanneal) as the temperature falls.
Single-stranded DNA from different species can be mixed together to identify the degree of similarity (as measured by complementary base pairs). Closely related sequences will join together (hybridise) more strongly as they share more complementary base pairs
Strength of hybrid molecule (and degree of similarity) can be measured by how much heat is required to separate the strands
How can homeobox (Hox) genes provide evidence of evolutionary change?
Homeobox genes = master developmental control genes that act at the top of genetic hierarchies. Provide instructions for all general body parts (ie. most animals have a head end, tail end, eyes, limbs, etc.)
The actual genes that determine the shape and structure of body parts (ie. eyesO are different between species, but the genes to grow an eye is the same
Hox genes indicate that all animals have common ancestry
As animals evolved and increased in complexity, the number of Hox genes also increased
What is selective/artificial breeding?
Selective breeding is a form of artificial selection, whereby humans intervene in the breeding of species to produce desired traits in offspring.
By breeding members of a species with desired traits, the trait’s frequency becomes more common in successive generations
Selective breeding provides evidence of evolution as targeted breeds can show significant variation in a relatively short period
Dog breeds show enormous amounts of variety due to the targeted selection of particular traits by man
What are gene pools?
Refers to the combination of all the genes (including alleles) present in a reproducing population or species.
A large gene pool has extensive genomic diversity and is better able to withstand environmental challenges.
A diverse population often contains enough genetic variation so that there will be an availability of suitable genes that are necessary for survival. This is the basic concept behind the theory of natural selection.
Populations with narrow gene pools containing low diversity are more likely to suffer from reduced fitness and are more susceptible to extinction.
What is natural selection?
The process through which populations of living organisms adapt and change. Natural selection increases the frequency of characteristics that make individuals better adapted and decreases the frequency of other characteristics leading to changes within the species.
Natural selection may produce phenotypic change over time. Direction of change will depend on the selection pressure
What is sexual selection?
A type of selection where the presence of a particular trait provides greater success in obtaining mates and reproducing. These traits may relate to fitness (ie. bigger, stronger males), but in some cases could actually be counterproductive to survivability (ie. bright plumage in birds makes them more visible to predators).
It can lead to a situation referred to as non-random mating, where not all individuals have the same opportunity to pass on their alleles/genes.
What is artificial selection?
The identification by humans of desirable traits in plants and animals, and the steps take to enhance and perpetuate those traits in future generations. Human intervention, essentially.
What are the three effects of selection on phenotype distribution in a species?
Stabilising selection
Directional selection
Disruptive selection
What is stabilising selection?
Stabilising selection favours individuals with intermediate phenotypes/variants. Extreme variations are culled, narrowing the width of distribution.
What is directional selection?
Favours one extreme over variants of the other extreme and intermediate areas. Shifts the distribution left or right (accordingly).
What is disruptive selection?
Favours both extremes while culling intermediate variants. Creates bimodal distribution. May occur when environmental conditions are varied or when the environmental range of an organism is large (can lead to speciation).
What do mutations give rise to?
Source of new alleles. Thus, mutations can change the frequency of existing alleles by competing with them.
Recurrent spontaneous mutations may become common in a population if they are not harmful and are not eliminated.
What is genetic drift?
Variation (random change) in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.
Genetic drift is greater in small populations.
Although genetic drift is a mechanism of evolution, it does not work to produce adaptations.
Sometimes survival is not related to fitness or selection pressure, yet it can lead to a change in the gene pool.
What is the Founder Effect?
The reduced genetic diversity which results when a population is descended from a small number of colonising ancestors.
When a small number of individuals migrate away from, or become isolated from their original population, they will have a small and probably non-representative sample of alleles from the parent population’s gene pool.
The colonising population may evolve in a different direction than the parent population.
__________ occur when the breeding population is reduced by 50% or more.
Population bottlenecks increase genetic drift, as the rate of drift is inversely proportional to the population size. They also decrease genetic diversity.
Lack of genetic diversity can result in:
Sperm abnormalities
Decreased fecundity (female fertility)
High offspring mortality rates
Sensitivity to disease
What is coevolution?
Where two (or more) species affect each other’s evolution.
ie. flower plants and pollinators; predator/prey relationships
What is speciation?
The process by which new plant or animal species arise.
A population of one species can only evolve into more than one species if groups within the population become isolated from each other by barriers that prevent exchange of genes (gene flow).
Two types of genetic isolation are….
Prezygotic isolation
Postzygotic isolation
Prezygotic isolation occurs…
…before fertilisation can occur (no offspring produced). Largely environmentally based, however prezygotic isolating mechanisms include:
Temporal: Occurs when two species mate at different times of year
Ecological: Occurs when two species occupy different habitats
Behavioural: Occurs when two species have different courtship behaviours
Mechanical: Occurs when physical differences prevent copulation/pollination
Postzygotic isolation occurs…
…after fertilisation (offspring are often neither viable or fertile).
Largely physiologically based, however postzygotic isolating mechanisms include:
Hybrid inviability: Hybrids are produced but fail to develop to reproductive maturity
Hybrid infertility: Hybrids fail to produce functional gametes (sterility)
Hybrid breakdown: F1 hybrids are fertile, but F2 generations fail to develop properly
__________ occurs when a physical barrier divides a population.
Allopatric Speciation
__________ occurs when species within the same area become reproductively isolated, usually due to some sort of behaviour change.
Sympatric Speciation
What is splitting in terms of speciation?
The process whereby a species splits into two populations that evolve differently until they eventually become separate species.
What is budding in terms of speciation?
The process whereby a small part of the species population could ‘bud off’ from the main part and evolve rapidly to form a new species. Ancestral species is retained.
__________ occurs when a common ancestral species evolves into a number of new species. These species have adaptations allowing them to occupy different niches.
Divergent Evolution
What is adaptive radiation?
A common example of divergent evolution, where rapid evolutionary diversification of a single ancestral line occurs. The diversification of a group of organisms into forms filling different ecological niches.
ie. the mammal diversification occurred after the extinction of the dinosaurs, which made niches available.
What is convergent evolution?
Where similar niches and selection pressures exist, species without a recent common ancestry may evolve to have similar physical characteristics, to suit the similar environment.
Certain marsupial and placental mammal species have evolved convergently to occupy equivalent niches on different continents; they are ecological equivalents
Rate of Evolution: Evolution occurs both within a species (--) and across the species barrier (--).
Microevolution, Macroevolution
Rate of Evolution: Two models of evolution via speciation are ________ and ________.
Phyletic Gradualism, Punctuated Equilibrium
What is phyletic gradualism?
Essentially ‘slow evolution’. If the environment remains stable, organisms may undergo very little change over time and evolution is slow and gradual.
The process is considered smooth and continuous (linear etc.), and any big changes are the result of the accumulation of many small changes over a long period of time.
What is punctuated equilibrium?
Essentially ‘rapid evolution’. After long periods with little or no change, an isolation event separates a small population of individuals.
With a different gene pool or bursts of mutations, this isolated group rapidly evolves into a separate species.
__________ describes evolutionary changes that occur over a relatively short period of geological time (such as between generations), and results in diversification within a species.
Microevolution.
Evolution within a single population. It works within a group of organisms that interbreed with each other and share a gene pool. It can be detected through changes in gene frequency over time.
Mechanisms for microevolution that can directly affect gene frequencies in a population:
Mutations
Gene flow (the transfer of genetic material from one population to another)
Genetic drift
Selection
Natural selection
Artificial selection
Sexual selection
__________ is evolution on a large scale over longer periods of time, generally above the species level (across species).
Macroevolution.
Encompasses larger trends and transformations in evolution. The basic mechanisms of microevolution (mutation, gene flow, genetic drift, natural selection) can produce macroevolutionary changes if given enough time.
Patterns of macroevolution include:
Stasis: some lineages remain unchanged for long periods of time
Characteristic changes: ie. gaining or losing body parts
Speciation: the rate and frequency at which branching occurs
Extinctions: this can be rare, frequent, or across many lineages (mass extinction events)
What is Hardy-Weinberg Equilibrium?
Hardy-Weinberg equilibrium is a principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors.
Based on the concept that every gene has two alleles (dominant/recessive)
When mating is random in a large population with no disruptive circumstances, the law predicts that both genotype and allele frequencies will remain constant because they are in equilibrium
What are the HWE disruptive circumstances?
Mutations: adds new alleles and is a source of variation
Natural selection: can increase/decrease certain phenotypes
Non-random mating (sexual selection): not all individuals will get to pass their alleles onto the next generation
Genetic drift: can randomly alter allele frequencies
Gene flow: can add or remove alleles in a population
What conditions (5) must be met for HWE?
Random mating → no sexual selection
No mutations → no change in gene flow due to creation of new alleles
Large population size → minimises effect of genetic drift
No migration → no introduction or removal of alleles
No natural selection → no alleles are ‘fitter’ than others
If these conditions aren’t met, the principle doesn’t apply and over time evolution can occur.
__________ is another name for cladograms. Cladograms with the least number of branches is likely the most accurate one (rule of parsimony).
Phylogenetic trees
Cladograms: __________ is the initial ancestor to all organisms within the cladogram (incoming line shows it originates from a larger clade).
Root
Cladograms: __________ corresponds to a hypothetical common ancestor that speciated to give rise to two (or more) daughter taxa. It typically denotes a ‘speciation’ event.
Node
Cladograms: __________ are the most distantly related species in the cladogram, which functions as a point of comparison and reference group.
Outgroups
Cladograms: __________ indicate a common ancestor and all of its descendants. Includes a node and all of its connected branches.
Clades.
What evidence are cladograms typically constructed from?
Molecular evidence, structural (morphological) features
What molecular evidence do scientists use when comparing species?
Non-coding DNA, gene sequences, amino acid sequences.
Non-coding DNA → provides the best means of comparison as mutations will occur more readily in these sequences.
Gene sequences → mutate at a slower rate, as changes to base sequence may potentially affect protein structure and function.
Amino acid sequences → may also be used for comparison, but will have the slowest rate of change due to codon degeneracy.
Amino acid sequences are typically used to compare distantly related species (ie. different taxa), while DNA or RNA base sequences are often used to compare closely related organisms.
What factors affect the molecular clock concept?
Different genes or proteins may change at different rates (ie. haemoglobin mutates more rapidly than cytochrome c)
The rate of change for a particular gene may differ between different groups or organisms
Over long periods, earlier changes may be reversed by later changes, potentially confounding the accuracy of predictions
Ancestral Primate: List the 7 main features of primate ancestors.
Arboreal (tree dwelling) habitat
Grasping hands and feet
Long, mobile limbs
Quadrupedal locomotion
Binocular vision
Upright sitting position
Nails instead of claws on most digits
Primate Characteristics: List 3 notable features that are unique to primates.
Superior intelligence
Complex social behaviour
Highly developed problem solving abilities
What are hominids?
The group consisting of **all modern and extinct Great Apes.
Includes humans, chimpanzees, gorillas
Hominids: List the anatomical features common to all hominids.
No tail
Semi-erect or fully erect posture
Broad chest, pelvis, and shoulders
Relatively long arms and mobile shoulder joints
Large brain
What are hominins? Give three examples (species).
The group consisting of modern humans, extinct human species, and all immediate ancestors. Essentially the point where bipedalism occurs (all hominins are hominids, but not all hominids are hominins).
Australopithecus
Paranthropus
Homo
Hominins: List anatomical features and habits.
Bipedal with modified feet, thigh bone, pelvis, spine
Large cerebral cortex (forebrain) → higher order functions are located in the cerebral cortex
Reduced canines (and teeth in general)
Prominent nose and chin, reduced eye ridges
Body hair short or very reduced
Highly sensitive skin
Complex social behaviour
List 5 human characteristics
Bipedalism
Larger brain
Increased intelligence
Teeth changes
Loss of body hair
Adaptations for Bipedalism: Humans are the only habitually bipedal primate. List the various adaptations needed for this evolutionary step.
Forward pointing big toe
Transverse arch to absorb impact
Foramen magnum at the base of skull
Carrying angle of the femur
Strong knee joint
Lower and broader pelvis
Strong gluteal muscles
Selection for Bipedalism: What were the factors that contributed to the evolution of bipedalism?
Carrying food and offspring
Locomotion; more efficient for long distance walking
Higher vision, able to see further over grasslands
Holding tools and weapons
Thermoregulation, less exposure to the sun, better cooling via evaporation
What were the two Australopithecine species?
Australopithecus afarensis
Australopithecus africanus
As many as four species of genus Australopithecus existed, ranging from southern Africa, through East Africa, to Chad in the north.
LUCY: What were the primitive features of Lucy (4.0-2.7mya, A. afarensis)?
The skeleton exhibits features consistent with a species adapted for walking bipedally
Possesses ‘primitive’ features normally associated with an arboreal existence
Human-like hands and teeth
Brain capacity of approximately 375-550cc
Apelike face with a sloping forehead, a distinct ridge over the eyes, flat nose, and chinless lower jaw
Between 1.0-1.5m tall (sexual dimorphism)
What is sexual dimorphism?
Distinct difference in size or appearance between the sexes of an animal, in addition to the sexual organs themselves.
What were the three main species from genus Paranthropus?
P. boisei
P. robustus
P. aethiopicus
Genus Paranthropus: What was the main food source for Paranthropus species? Are they considered direct ancestors of humans?
Paranthropus were a group of species that exploited low-grade vegetable sources (nuts, root tubers, seeds), resulting in (megadont) species with very large teeth.
Initially classified as Australopithecines, it is now thought they were descendants of that group, but that none of the species were direct ancestors of humans.
What were the 6 main species of genus Homo?
H. habilis → 2.4 - 1.6mya; Eastern and possibly Southern Africa
H. ergaster → 1.8 - 1.4mya; Africa
H. erectus → 2mya - 400 000ya; Africa, Asia, Indonesia, possibly Europe
Archaic H. sapiens → 400 000 - 100 000ya; Africa, Asia, Europ
H. neanderthalensis → 150 000 - 30 000ya; Europe, Western Asia
H. sapiens → 130 000ya - present; Africa and Western Asia before going global
Homo erectus: What was the significance of H. erectus?
Early example of increased brain size (from 850cc - 1100cc)
Speech → enlarged Broca’s area (region of brain for speech), structure of jaw and throat
Developed tools, weapons, fire, and learned to cook food
Face had massive jaws with huge molars, no chin, thick brow ridges, and long low skull
Sturdier in build and much stronger than the modern human
What were the adaptations for running?
Loss of hair, sweating for cooling, high SA:V
Elongated legs
Nuchal ligament (back of neck) to stabilise the head
Thickened joint surfaces in knees and other high impact joints
Plantar arch in foot acts as spring (shock absorption)
Achilles tendon
Well-developed gluteus maximus
More muscles attached to lower spine for support
What were the selection pressures for reduced body hair?
Parasite control → particularly important when early hominins began to use a regular ‘home base’.
Retention of head hair → hair on the head (and the shoulders, to a lesser extent) reflects and radiates solar radiation (heat) before it reaches the skin.
Thermoregulation → well developed sweat glands allowed for heat loss at an astounding 700watts/square meter of skin (a capacity not approached by any other mammal).
Evolution of the Human Brain: What two areas have become highly developed in the modern human brain?
Broca’s area concerned with speech
Wernicke’s area concerned with comprehension of language
Intelligence is not just a function of brain size; relative brain size appears to be more important (brain size compared to body size).
Modern humans have a brain volume three times larger than that predicted for an average monkey or ape with our body size.
another important factor is the organisation of the brain, evident in the areas concerned with spoken language.
Homo neanderthalensis information :)
350 000 - 30 000ya
Shorter, more robust frame
Skull has low forehead, strong brow ridges and occipital bone (most posterior cranial bone)
Broad nasal cavity (to warm air)
Barrel shaped chest and compact body to conserve heat
Evidence of tools, fires, care for injured people, burial customs, music
‘Cro-Magnon’ is another term for…
… Homo sapiens.
H. sapiens evolved in Africa - better suited for hot climate
Moved to Europe approximately 90 000ya
Brain is around 1400cc with a high frontal lobe/forehead
Complex tools, agriculture, music, art, abstract concepts (imagination, emotional intelligence)
Homo sapiens information :)
The first anatomically modern humans appear possibly as early as 300 000ya in Africa and the Middle East.
They underwent a sudden cultural revolution about 40 000ya, with the appearance of Cro-Magnon culture.
They were skilled hunters, tool-makers and artists (indicated by cave art and music).
Did the Neanderthals go extinct?
There was a period when both Neanderthals and H. sapiens lived in Europe - sometimes occupying the same areas and caves.
Did the smarter H. sapiens outcompete the Neanderthals? Did they interbreed? Genetic evidence suggests yes.
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