Reproduction and Anthropogeny Flashcards
What is anthropogeny?
Study of the origins and development of humans
Where did Charles Darwin gather his data?
Voyage of HMS Beagle (1831-1836) by observing wildlife and native characters from South America and surrounding islands.
What does the following suggest?
“Species are variable and can adapt to changes in environment, which leads to increased survival and reproduction within favoured groups, causing the least favourable variants to perish”
Natural selection
How is the peppered moth a good example of natural selection?
- Shows an adaptation to Peppered moths for survival.
- Prior to the Industrial Revolution, most peppered moths were white (which provided good camouflage against light tree bark and lichens)
- Industrial fallout killed lichen and soot covered light tree bark, which made white moths cleary visible to prey and the numbers dropped.
- Which caused the black peppered moth numbers to grow, passing on the phenotype to more generations.
Where did modern humans originate?
Africa around 200k years ago.
Explain skin colour as a form of natural selection
- As humans lost body hair and increase sweat glands to better regulate temp, the skin was exposed to damaging UV radiation.
- In those areas that receive more UV radiation, darker skin pigment reduces the harshness of the rays.
- But in places where there is less UV, lighter pigment is needed to ensure Vit D is received.
Explain lactose intolerance as a form of natural selection
What does natural selection result in?
Adaptations.
What are adaptations?
Characteristics of species that change over time to better suit the environment.
What is variability?
Range of genetic differences within a species.
What is variability caused by?
Gene mutations, gene flow and genetic drift.
How can gene mutations cause variability?
- By having errors in DNA it alters the genome and may create new alleles which then change the phenotype.
What is gene flow?
- Transfer of gene variants from one population to another.
- Occurs because of migration into or out of a population.
- Results in admixture of hybridisation.
What is genetic drift?
- Random changes in gene variant frequency.
- Potential loss of alleles in a new small population.
What is the founder effect?
- The reduction of genetic variability when a small population is isolated.
What are some examples of the founder effect?
- Small population of Quebec established by French pioneers
2500 settlers who remained socially isolated
Approx 14 generations
Extensive disequilibrium Reduction in genetic variation
Increase in heritable diseases
Myotonic dystrophy
1 in 500 in Quebec
1 in 10,000 in Europe
What is homologies?
Similarities between organisms.
What is the number of genes and genome size in most mammals?
21000 genes and 3.2 billion base pairs in the genome.
By what % do human and chimpanzee DNA differ?
1.2%
Are human and mouse genes similar?
Yes, around 85% similar
What are the 4 major events in human evolution?
Terrestrialism, Bipedalism, Encephalisation and Civilisation.
What is Terrestrialism?
Living on the ground rather than in trees
What is Bipedalism?
Walking on two limbs
What is Encephalisation?
Brain development to enable higher-order functioning.
What is Civilisation?
Development of a complex societal and cultural system.
What is the history of humans?
Australopithecines (4-1.6 mya), Homo Habilis, Homo erectus & homo ergaster, Archiac homo sapiens, Homo (sapiens) neanderthalensis and Homo sapiens.
What are the advantages of sexual reproduction?
What are the disadvantages of sexual reproduction?
What are the areas of the Male reproductive system?
What are the sections of the reproductive system?
What are the Accessory glands?
What do the Leydig cells produce?
