Week 2 Flashcards
genotypes
A person’s genotype is their unique sequence of DNA. More specifically, this term is used to refer to the two alleles a person has inherited for a particular gene. Phenotype is the detectable expression of this genotype – a patient’s clinical presentation.
Phenotype
Phenotype refers to an individual’s observable traits, such as height, eye color and blood type. A person’s phenotype is determined by both their genomic makeup (genotype) and environmental factors.
Adaptation
A biological characteristic with a heritable basis that improves reproduction and/or survival and results from evolution by natural selection.
- takes time
- not goal-directed (what will be helpful or not, we cannot pick)
- not all characteristics that survive for generation after generation are adaptions in the sense of improving chances of survival and reproduction.
- whether a particular gene helps or hinders survival and reproduction depends on a) the environment in which the problem is faced and b) other genes
neoteny
the retention of juvenile features in the adult animal.
heterochrony
Heterochrony can be defined as “change to the timing or rate of developmental events, relative to the same events in the ancestor”
Heritability
- the estimation of heritability does nothing to show how genes work
- depends on the particular population at that particular time with the particular measuring instruments
- only be expressed as a percentage if there is variation in the population
- do not clarify effects that are environmental as well as genetic
Phenotypes and genotypes
Your genotype is your complete heritable genetic identity. It is your unique genome that would be revealed by personal genome sequencing. However, the word genotype can also refer just to a particular gene or set of genes carried by an individual.
In contrast, your phenotype is a description of your actual physical characteristics. This includes straightforward visible characteristics like your height and eye color, but also your overall health, your disease history, and even your behavior.
Memory in utero
In-utero memory is important for the development of memory in humans. Many factors can impair in-utero memory and its functions, primarily maternal actions. In utero memory is important for parental recognition, and facilitates the bond between child and parents. One of the most important types of memory is that which stores information contributing to the maternal bond between infant and mother.
Early foetal and newborn sensory capabilities
The sensory development in the months leading up to birth can be affected by many factors. Select each of the titles to explore the sensory areas of hearing, smell, vision and taste, as it applies to infant development, in more detail.
Hearing:
The auditory system is fully functioning at birth and is one of the first systems to develop in the foetus. The ear develops from the inside out. Given that babies are able to hear well before they are born it is natural to ask what they might be listening to and is an area of active research.
Smell:
Smell is very important for newborn infants. They use their ability to discriminate smells to recognise their mother through the smell of her breast milk. In a study by MacFarlane (1975) six-day-old infants were tested by placing a pad worn by their mother to catch seeping breast milk on one side of their head and a pad from another breast-feeding mother on the other. Babies turned their heads toward the side of their mother’s pad, preferring the familiar smell.
Taste:
Newborns have a preference for sweet tastes and they show aversion to a sour taste just like adults, puckering up their lips and showing a ‘disgusted’ expression. Tolerence for salt develops in the months after birth and the preference for plain water rather than salty water begins to disappear by four months after birth.
Vision:
Relative to adults, newborns are not able to perceive fine detail. They can discriminate between a uniform grey surface and stationary black and white stripes three millimetres wide. Visual acuity develops steadily over the next few months and by the age of three months, infants can perceive stripes that are less than half a millimetre wide.
Chapter 2 Biological bases of child development: Evolution and genes (Links to an external site.) (Meadows, 2017, pp. 33–60) will provide a good understanding of how genetics relate to early child development.
- Darwins Natural Selection - 1. individuals vary in how successfully they can survive and reproduce, 2. individuals vary in physical and psychological characteristics, 3. some characteristics of the parents can be inherited by their children predictably and whether or not child or parents chooses, the family noise, the freckles, the big feet.
- by teaching, modelling or imitation, fluency in English, an enthusiasm f opera or gardening
- individuals with lots of descendants have copies of their own inheritable. fewer descendants will tend to hand down fewer inheritable characteristics.
Adaptation - based on the genes we inherited from our ancestors
- nature in adaptation. 1. takes time, 2. process of genetic adaptation is not goal-directed, 3. not all characteristics that survive for generation after generation are adaptations in the sense of improving the individuals chances of survival and reproduction, 4. whether a particular gene helps or hinders survival and reproduction depends on a) the environment in which the problem is faced and b) other genes.
Humans reproductive strategy implies they will invest in their offspring:
- ‘r-selection’ reproductive strategy produces a large number for the next generation rapidly and it can result in rapid population growth, then r-selection may be effective in keeping the individuals bloodline going.
- ‘k-selection’ - some species are large at birth and grow to a large adult size, reach reproductive maturity slowly, have few offspring per litter, invest a lot of parental care in these offspring so that most of them survive to reproduce and die at an older age
Genes and Child Development:
- 46 chromosomes containing structures of deoxyribonucleic acid (DNA), doubel helix which is made up of 4 bases arranged in pairs between the helical backbones. Every cell contains 30 billion base pairs of DNA. 22 matched pairs and 1 unmatched pair. 20 - 30k gene units in genome.
- Deafness = caused bu proteins called myosins that form the hair cells that respond to sound waves, if they done form properly, they become deaf.
- monozygotic = twins from the same egg
- dizygotic = twins from two eggs
Genes and Experiences as Influences on Development:
- heritability. 1. doesnt show how genes work, 2. not generalisable, 3. only be expressed as a % if there is variation in the population, 4. does not clarify effects that are obviously environmental as well as genetic. It does however, 1. there is significant genetic contribution to the development of most normal and pathological psychological traits with heritability around 20% to 60%. 2. genes contribute more to diffences in the brain regions that envolved relatively recently such as the cortext, 3. lower at risk populations with tough environments than it is in populations whose environments are more benevolent, 4. rises in child to adolescnece to adulthood.
Genetic Anomalies and Different Development:
- heterozygous = have a 1 copy of abnormal allele while the version inherited from the other parent is normal
- recessive genetic disorders occur more frequently if the parents are themselves genetically closely related
Gene Expression:
- specific to particular types of cells and regions of the body, and particular periods of development
Other:
- there is an interaction between the variants of the serotonin transport genes and experience of life events that is associated with major depression.
- ADHD/ADD = gene-environment interaction.
- Phenylketonuria = defective gene leads to the absence of a particular enzyme, phenylalanine hydroxylase, from teh body; individual is unable to make it.
Chapter 3 Introduction to infancy (Links to an external site.) (Harris & Westermann, 2014, pp. 47–64) covers information about early physical and sensory abilities of young infants.
- Feotal Alcohol Syndrom - drinking during pregnancy
- Pregnant women with high levels of cortisol are more likely to be depressed, having a premature birth and lower birth weight
- Premmies have 12 weeks at hospital
- mental age - this gives an indication of a childs level of cognitive function in years and months
- chronological age - actual age
- newborns have larger heads and take a long time to become mobile, so thats why motor skills are under developed
- stepping reflex - when a baby is supported in a standing position and the feet are brough into contact with the surface, the baby responds by making stepping movements.
- power grip - a grip in which the fingers wrap around the objects
- precision grip - full opposition of the fingers and thumbs only found in humans.
- between 6 - 12 months less power grip more precision grip
- pre-reaching - movements of the arm and hand made by newborns towards an attractive object
- goal-directed reaching - the ability to successfully attain a desired object around 3 - 4 months old.
Fetal memory: Does it exist? What does it do? (Links to an external site.) (Hepper, 1996, pp. 16–20).
- newborns have been shown via a variety of learning paradigms, habituation, classical conditioning, associative learning and imitation to possess a functioning memory.
- it is more likely that memory begins prenatally and the period of birth merely marks a transitions from memory functioning in utero to memory function ex utero.
- remains to be determined exactly why some fetuses exhibit conditioning and others do not.
- number of reasons fetus should have functioning memory.
- research into fetus memory, the existence of which is no longer in doubt.
- may be more important for breast feeding.
DB
I have decided to focus on infant hearing, smell, taste and vision. These newborn capabilities are influenced by both genetics and environment and are developed and used differently by each individual. The bodily anatomy are developed in utero, as a baby grows body parts, such as ears, nose, mouth and eyes. The ways that these genetically created parts are used though, is different in each individual, based on their external environment. In utero, a baby can hear from early on, and no two babies will be hearing the same thing. Depending on what the parent’s are listening to or speaking about, will change what the baby is listening to and how they will develop a different personality and views on the world and themselves.
DB
Sitting, standing and walking is effected both by genetics and the infants environments. Babies tend to follow developmental milestones based off the ages the parents began to develop. This would be when their leg muscles began to develop or become stronger to hold themselves up. However, environment pays a big role in this and is effected by multiple factors. Some of these factors include do they have older siblings that they are always around and trying to copy. Do the child’s parents sit with them and practice helping them stand and walk on their own daily. Is the child participating in activities and toys that will help promote these positions.
DB
Epigenetics is quite interesting and VERY in-depth, I can’t wait for the day they work out epigenetics including psychology, that would be creepy and awesome at the same time. I know fetal memory can be considered similar, but I am more wondering about that link to what we call “past lives” and such, for example, my earliest memory, is being bound in cloth, warm, and looking up at a very bright ceiling; there are plastic see through walls around me and I can’t talk.
Hand control is very much a mix of both, genetics plays a factor due to the possibility of brain or cognitive disorder being expressed upon birth or detected during foetal development through means of blood testing of the mother or amniocentesis (eg: Downs Syndrome Testing) in which the genes are deleted or replicated poorly in Chromosome 21 (Trisomy). If an infant is born with this condition their hand coordination and thus their movement may be limited to only a small number of movements, or even expressed as a tic, such as Cerebral Palsy or similar conditions.
The environment matters also, infants are naturally very curious individuals and love to touch, grasp, and move things around so that they can gain a better understanding of the world around them; infants who are denied these activities can develop issues with movement or hand to eye co-ordination purely due to not being able to explore or feel their environments. Involving kids, at a young age, with these skills can help them fine-tune movements are build confidence in how they are doing them
