Transcript Objective 11-2

Intro-Life Expectancy-Sensory-Abilities
OBJECTIVE 11-2
INTRO
 True/False
 Older People Become more susceptible to short-term illnesses.
 During old age many of the brains neurons die
 If they live to be 90 or older, most elderly people eventually become
senile
 Recognition memory-that ability to identify things preciously
experienced-declines with age
 Life satisfaction peaks in the fifties and then gradually declines after
age 65
Life Expectancy

Worldwide, life expectancy at birth increased from 49 years in 1950 to 67 in 2004-and to 80 and
beyond in some developed countries

Combined with decreasing birthrates making the elderly population bigger

By 205 about 35% of Europe’s population will be over 60

Life expectancy differs for males and females; males are more prone to dying. Although 126 male
embryos begin life for every 100 female who do so, the sex ratio is down to 105 males for every
100 females at birth

During the first year, male infants; death rates exceed females’ by ¼

Women outlive men by 4 years worldwide and by 5-6 years in Canada, United States, and
Australia.

By age 100 females out live males 5 to 1

Even if no one died before age 50, cancer, heart disease, and illnesses were eliminated, average
life expectancy would increase only to 85 or a few more years

Once We’ve fulfilled our gene-reproducing task, there are no natural selection pressures against
genes that cause degeneration in the later life
Sensory abilities

Physical decline starts in early adulthood, but we are not aware until later
life.

Visual sharpness diminishes, and adaptation to changes in light levels slows.

Muscle strength, reaction time, and stamina also diminish noticeably, as do
hearing, distance perception, and the sense of smell

In late life the stairs get steeper, the print gets smaller, and people seem to
mumble more.

The eye’s pupil shrinks and its lens becomes less transparent, reducing the
amount of light reaching the retina. A 65-year-old retina receives only about
one-third as much light as its 20-year-old counterpart

To see as much as the 20-year-old, the 65-year-old needs to receive 3 times
as much light