Human adaptation to environmental conditions. Notions of human adaptation and acclimatization, mechanisms of adaptation

Содержание

Слайд 2

INTRODUCTION….. Humans have biological plasticity,or an ability to adapt biologically to

INTRODUCTION…..

Humans have biological plasticity,or an ability to adapt biologically to our

environment.An adaptationis any variation that can increase one’s biological fitness in a specific environment; more simply it is the successful interaction of a population with its environment.Adaptations may be biological or cultural in nature. Biological adaptations vary in their length of time, anywhere from a few seconds for a reflex to a lifetime for developmental acclimatization or genetics.
The biological changes that occur within an individual’s lifetime are also referred to as functional adaptations.
Слайд 3

CONTINUE…… What type of adaptation is activated often depends on the

CONTINUE……

What type of adaptation is activated often depends on the severity

and duration of stressors in the environment.
A stressor is anything that disrupts homeostasis, which is a “condition of balance, or stability, within a biological system…”(Jurmain et al 2013: 322).
Stressors can be abiotic, e.g., climate or high altitude, biotic, e.g., disease, or social, e.g., war and psychological stress. Cultural adaptations can occur at any time and may be as simple as putting on a coat when it is cold or as complicated as engineering, building, and installing a heating system in a building
Слайд 4

TYPES OF HUMAN ADAPTATION…. Genetic adaptations can occur when a stressor

TYPES OF HUMAN ADAPTATION….

Genetic adaptations can occur when a stressor is

constant and lasts for many generations (O’Neil 1998-2013). The presence of the sickle cell allele in some human populations is one example. Keep in mind that genetic adaptations are environmentally specific.In other words, while a particular gene may be advantageous to have in one environment (AKA a genetic adaptation), it may be detrimental to have in another environment. z Ac
Слайд 5

ACCLIMIZATION….. This form of adaptation can take moments to weeks to

ACCLIMIZATION…..

This form of adaptation can take moments to weeks to occur

and is reversible within an individual’s lifetime no matter if it occurs when one is a child or an adult. ▪ Short-termacclimatizationcan occur within seconds of exposure to a stressor.This type of response quickly reverses when the stressor is no longer present. Imagine stepping out of an air-conditioned building or car into a 90 degree day. Your body will quickly begin to perspire in an attempt to cool your body temperature and return to homeostasis. When the temperature declines, so will your perspiration. Tanning is another shortterm response, in this case to increased UV-radiation exposure especially during summer months, which can occur within hours. Tans are generally lost during the winter when UV-radiation decreases
Слайд 6

Developmental Acclimatization….. ▪ Developmental acclimatization occurs during an individual’s growth and

Developmental Acclimatization…..

▪ Developmental acclimatization occurs during an individual’s growth and development.

It’s also called ontological acclimatization or developmental adjustment. Note that these cannot take place once the individual is fully grown. There is usually a “magic time window” of when the acclimatization can occur. This adaptation can take months to years to acquire. ▪ A famous example of this is those who have grown up at high altitude vs. those who have moved to high altitude as adults. Those who were born at high altitude tend to develop larger lung capacities than do those who were not born at high altitude, but moved there later in life. However, developmental adjustment occurs in response to cultural stressors as well. Intentional body deformation has been documented throughout human history. The ancient Maya elite used cradle boards to reshape the skull. Foot binding in China, now an illegal practice, was considered an mark of beauty and enabled girls to find a wealthy spouse.
Слайд 7

Human genetic adaptations and human variation….. ▪ Skin color ▪ Body size and shape ▪ Race

Human genetic adaptations and human variation…..

▪ Skin color
▪ Body size

and shape
▪ Race
Слайд 8

DEFINATION OF HUMAN ADAPATION….. Any alteration in the structure or function

DEFINATION OF HUMAN ADAPATION…..

Any alteration in the structure or function of

an organism or any of its parts that results from natural selection and by which the organism becomes better fitted to survive and multiply in its environment. ▪ a form or structure modified to fit a changed environment.
the ability of a species to survive in a particular ecological niche, especially because of alterations of form or behavior brought about through natural selection.
Слайд 9

CONTINUE…. This adaptation processes-to-pathways framework is then deployed to consider human

CONTINUE….

This adaptation processes-to-pathways framework is then deployed to consider human responses

to biodiversity change caused by an aggressive ‘invasive’ plant, Lantana camara L., in several agri-forest communities of southern India.
The results show that a variety of adaptation processes are developing to make Lantana less disruptive and more useable—from avoidance through mobility strategies to utilizing the plant for economic diversification. However, there is currently no clear synergy or policy support to connect them to a successful long-term adaptation pathway.
These results are evaluated in relation to broader trends in adaptation analysis and governance to suggest ways of improving our understanding and support for human adaptation to biodiversity change at the household, community, and regional livelisystem levels, especially in societies highly dependent on local biodiversity for their livelihoods
Слайд 10

Acclimatization of human adaptation… • Developmental acclimatization occurs during an individual's

Acclimatization of human adaptation…

• Developmental acclimatization occurs during an individual's growth

and development. It's also called ontological acclimatization or developmental adjustment. ... There is usually a “magic time window” of when the acclimatization can occur. This adaptation can take months to years to acquire
Слайд 11

Mechanism of adaptation….. • Wallace believed that the evolution of organisms

Mechanism of adaptation…..

• Wallace believed that the evolution of organisms was

connected in some way with adaptation of organisms to changing environmental conditions. In developing the theory of evolution by natural selection, Wallace and Darwin both went beyond simple adaptation by explaining how organisms adapt and evolve.
The idea of natural selection is that traits that can be passed down allow organisms to adapt to the environment better than other organisms of the same species. This enables better survival and reproduction compared with other members of the species, leading to evolution.
Wallace believed that the evolution of organisms was connected in some way with adaptation of organisms to changing environmental conditions. In developing the theory of evolution by natural selection, Wallace and Darwin both went beyond simple adaptation by explaining how organisms adapt and evolve.
The idea of natural selection is that traits that can be passed down allow organisms to adapt to the environment better than other organisms of the same species. This enables better survival and reproduction compared with other members of the species, leading to evolution.
Слайд 12

CONTINUE…. • Organisms can also exhibit behavioral adaptation. One example of

CONTINUE….

• Organisms can also exhibit behavioral adaptation. One example of behavioral

adaptation is how emperor penguins in Antarctica crowd together to share their warmth in the middle of winter. • Scientists who studied adaptation prior to the development of evolutionary theory included Georges Louis Leclerc Comte de Buffon.
He was a French mathematician who believed that organisms changed over time by adapting to the environments of their geographical locations. Another French thinker, Jean Baptiste Lamarck, proposed that animals could adapt, pass on their adaptations to their offspring, and therefore evolve.
The example he gave stated the ancestors of giraffes might have adapted to a shortage of food from short trees by stretching their necks to reach higher branches. In Lamarck’s thinking, the offspring of a giraffe that stretched its neck would then inherit a slightly longer neck. Lamarck theorized that behaviors aquired in a giraffe's lifetime would affect its offspring.
However, it was Darwin’s concept of natural selection, wherein favorable traits like a long neck in giraffes suvived not because of aquired skills, but because only giraffes that had long enough necks to feed themselves survived long enough to reproduce. Natural selection, then, provides a more compelling mechanism for adaptation and evolution than Lamarck's theories.
Слайд 13

Слайд 14

Adaptation is biological and social…. • To globally summarize, biological adaptation

Adaptation is biological and social….

• To globally summarize, biological adaptation can

be defined as “is adapted a living being.” This short cut that was inspired by Laborite (1976) introduced the idea that, if a being lives and reproduces, it is because it has adjusted its biological functions to its external conditions. Morin adheres to this general idea by affirming that adaptation is the prime and general condition of all existence (Morin, 1985).
In greater detail, biological adaptation designates above all a process that can be transposed at an individual level, resulting from genetic organization at a cellular level.
Thus, the immune system is capable of perception and acquisition on a physiological level. This process is then qualified as “acclimatization” or “apprenticeship” (Prochiantz, 1997; Stewart, 1994). Adaptation is biological and
Слайд 15

Слайд 16

CONTINUE….. The LEGO bricks analogy is often used to explain how

CONTINUE…..

The LEGO bricks analogy is often used to explain how each

essential, elementary functions are insured by distinct biological modules which are exquisitely adapted to their particular role (see for instance Csete et Doyle, 2002). This modular organisation is robust and at the same time flexible: when a new trait emerges, natural selection does not start from scratch, but from the available modules: existing organs, tissues and cells, existing genes and gene networks. By combining modules—the LEGO bricks— within an organism it is possible to make something new.
A common theme that has emerged from analyses in evolutionary biology is thus that organisms are robust and flexible systems. If the surroundings of an organism change, its developmental systems provide the ability to adapt to achieve and maintain some function (Breuker, 2006). Robustness and flexibility are thus two antinomic properties that result from modularity.
This “property of the systems that are susceptible to deforming themselves in a coherent and autonomous manner in order to respond to internal and external stress,” (Lambert and Rezsöhazy, 2004, p.304) is called plasticity and is seen as the real “adaptive capacity” of life.
Слайд 17

Слайд 18

Слайд 19

LINKS FROM YOUTUBE….. ▪ https://www.youtube.com/watch?v=dtvGUWG3Rbk ▪ https://www.youtube.com/watch?v=sLMZwwhSZQg

LINKS FROM YOUTUBE…..

▪ https://www.youtube.com/watch?v=dtvGUWG3Rbk
▪ https://www.youtube.com/watch?v=sLMZwwhSZQg