The big picture 3 Flashcards
What do phenotypes evolve to do?
Preserve or enhance Darwinian fitness (survival to reproduce)- not health
What is development important in producing?
Phenotypes and operates fast across generations
hence the concept of evolutionary developmental biology (evo-devo)
What do developmental predictions establish?
Phenotype through plasticity- to mate later environment. Mismatch between phenotype and environmental challenges?
Cultural evolution is very important to humans (this is an evolutionary theory of social change)
Laws of variation, in the origin of species by means of natural selection (1859)- Charles Darwin
“It is known to furriers that animals of the same species have thicker and better fur the further north they live; but who can tell how much of this difference may be due to the warmest-clad individuals having been favoured and preserved during many generations, and how much to the action of the severe climate?”
What was the rediscovery of Mendel’s laws of inheritance?
Animals have fur coats that are dependent on season and temperature
And this is passed on through the generations
What are Mendel’s laws of inheritance?
The Mendel’s laws of inheritance include law of dominance, law of segregation and law of independent assortment. The law of segregation states that every individual possesses two alleles and only one allele is passed on to the offspring.
What did embryologists stress and look for?
Embryologists stressed similarities and looked for models where environmental influences did not confuse the picture…
What are the two things to be considered under developmental biology?
Genetic determinism
Genetic programme for development, where all information for task is contained in the programme and it’s not affected by the environment
What is included under evolutionary biology and who was involved in some ideas?
Neo-Darwinism (Romanes 1895)
The modern synthesis from 1930s (E.Mayr and other later)
Variation (genes, random)
Selection
Inheritance (genes)
Selection on genotype not phenotype
Whats the central dogma and which scientists came up with this idea?
DNA –> RNA –> Protein (the pattern of information that occurs most frequently in our cells)
J Watson and F crick in 1953
How does the mothers body influence child development?
Genetic Epigenetic Environment
The mothers body influences her child’s development from the moment of conception
Her body composition, diet and lifestyle teach her baby about the world in which she lives
But what if his world turns out to be different?
Whats non-genomic inheritance?
During human evolution we have adapted to stay healthy in environment
Wide healthy range, only true if development is optimal
If this is impaired the range moves down and is shrunk in size
This increases the risk of disease
This comes up with the concept of mismatch
Life course model of risk
A mismatch pre- and post-weaning diet has window of exposure- and sex-specific effects on energy homeostasis, adiposity, and cardiovascular function in mice
Dietary mismatch between maternal diet during pregnancy and post weaning offspring diet (increased intra-muscular fat deposition)- by Oil red O staining
When there is a secure developmental environment, what do the organisms invest in?
When there is a threatening developmental environment, what does the organism do to adapt?
When testing mismatch ideas in humans what was observed?
developmental factors amplify effects of later lifestyle on type 2 diabetes risk
The lower the birth rate, the higher the risk of diabetes
Poor start to life, coupled with bad lifestyle score puts on at a greater risk for diabetes
Testing the mismatcg hypothesis in UK children
Nutritional/ energy balance
Do such developmental processes operate in humans- e.g., to favour survival in the face of severe challenge?
Developmental predictions to survive famine?
Trade-offs can have a cost later
Tell me how those who are adult survivors of severe malnutrition are affected by the glucose tolerance test?
Glucose (A) and insulin (B) profiles during a 75-g OGTT in adult survivors of severe malnutrition as well as community or sex and birthweight-mismatched controls
Children with Marasmus when challenged with glucose tolerance test had a higher risk of diabetes compared to those with kwashiorkor
NB. glucose tolerance test
The screening test is called an oral glucose tolerance test (OGTT), which takes about 2 hours. It involves having a blood test in the morning, when you have not had any food or drink for 8 to 10 hours (though you can usually drink water, but check with the hospital if you’re unsure). You’re then given a glucose drink.
The effect of urbanisation on body weight- India
Tell me about the evolved phenotype: placental glucose transfer is not transport limited
What effect does gestational diabetes have on offspring?
Changed shape of pelvis for bipedalism
Of all primates, humans have the biggest brains at birth
All human babies are potentially mismatched- maternal constraint of foetal growth
Constraint bigger in primipara, short stature, poor diet, smoking
Obesity (BMI >95th percentile) at age 4 years according to maternal first-trimester BMI
Mean % body fat from skinfold thickness in 276 men and women age 28-31 years
Maternal constraint does not have ant relevance in high income countries, with good medical care… or does it??
Perinatal mortality in 1,170,534 births >28 weeks, 2000-2008 in Netherlands
Age at menarche…
