http://video.nationalgeographic.com/video/player/animals/reptiles-animals/lizards/flying_reptiles.html...

http://video.nationalgeographic.com/video/player/animals/reptiles-animals/lizards/flying_reptiles.html http://video.nationalgeographic.com/video/player/animals/birds-animals/penguins/penguin_galapagos_pelican_co

mpetition.html

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giraffe_lifestyle.html http://video.nationalgeographic.com/video/player/animals/mammals-animals/bears-and-pandas/

bear_polar_momsandcubs.html

2008 Fall Lecture 3 SCIE 103 Life Sciences 1


Define: Biology Biology is the science of life (from the Greek words bios = life and logos

= reasoned account). It is concerned with the characteristics and behaviors of organisms, how species and individuals come into existence, and the interactions they have with each other and with their environment. Biology encompasses a broad spectrum of academic fields that are often viewed as independent disciplines. Together, they study life over a wide range of scales.

The study of living organisms and their vital processes. The two main divisions of biology are zoology, the study of animals, and botany, the study of plants. Other biological disciplines include physiology, cytology, embryology, ecology, anatomy, morphology, genetics, biochemistry and molecular biology.

The science of life and of living organisms, including their structure, function, growth, origin, evolution, and distribution. It includes botany and zoology and all their subdivisions.

The science that studies living organisms Characteristic life processes and phenomena of living organisms A class located suspiciously near the cafeteria


Characteristics of life

All living things maintain a high degree of order and complexity

All living things are part of larger systems of matter and energy

All life requires liquid water and depends on chemical reactions that take place in cells

Living things regulate their use of energy and respond to their environments

Organisms grow and develop All living things share the same genetic code, which is

passed from parent to offspring by reproduction All living things on Earth are descended from a

common ancestor



All living things maintain a high degree of order and complexity With time, things become disordered. However,

living systems tend to overcome this tendency by taking energy and materials from the environment. The energy and materials are used to maintain order and conduct various activities. Life exhibits order- We see order at many levels in the

world and can easily appreciate how a high degree of order can lead to efficient systems (engines, microprocessors, etc.). Yet the most highly ordered and complex ones are living systems themselves.



Levels of Organization: Subatomic particles Atoms Molecules Organelles Cells Tissues Organs Organ Systems Organisms Population Community Ecosystem Biosphere

Levels of Organization:Atoms

Biosphere

Cells

Community

Ecosystem

Molecules

Organ Systems

Organelles

Organisms

Organs

Population

Subatomic particles

Tissues

All living things are part of larger systems of matter and energy

One of the most common recurring themes in biology is that levels of organization exist in the biosphere: increasing order and complexity at one level leads to stability and the existance of higher levels. Although existance at one level depends on order at lower levels, each level also exhibits its own emergent properties, characteristics not exhibited at lower levels. Hence, it always appears as though the "whole exceeds the sum of its parts".

http://www.biologyinmotion.com/organize-it/



All life requires liquid water and depends on chemical reactions that take place in cells Life exhibits metabolism- Maintenance of life is

dependent on expenditure of energy to do work. Once an organism has either manufactured its own food or taken in food from the environment, complex chemical reactions called metabolism ensue. The purpose of such reactions is to break down molecules into simpler ones which are used either to repair old structures, build new ones or unlock the energy within the molecules to be used for life's processes. Hence, metabolism is a manifestation of work.



Living things regulate their use of energy and respond to their environments Homeostasis allows life forms to exist as self-

regulating systems. Homeostasis is a phenomenon whereby a state or process (for example, within an organism) is regulated automatically despite the tendency for fluctuations to occur.


Characteristics of life Organisms grow and develop

All individuals' lives end and disorder ensues. What allows for continuation of life through time? Organisms generate similar copies of themselves, which become members of the next generation. Hence, each species exhibits a characteristic life history, with predictable events. The "program" ensuring that an appropriate developmental sequence occurs is present at the time of birth and derived from the parents. This program is in the form of a chemical, DNA.

Reproduction- This is the phenomenon whereby organisms produce offspring. This is the most important characteristic allowing the continuity of life as we know it.

Development- Offspring are generally smaller and simpler than their parents. All phenomena relevant to an organism's maturation are collectively called development (ontogeny).

http://embryo.soad.umich.edu/resources/morph.mov



All living things share the same genetic code, which is passed from parent to offspring by reproduction Genes- The units of inheritance which guide development

of specific physical, chemical, and behavioral traits in a living organism are genes which are comprised of DNA. The molecules of DNA exhibit a high degree of structural integrity (insuring that characteristics are inherited in a precise manner) yet retain some capability to be modified structurally and functionally via mutation. The use of information-bearing molecules by all lifeforms is important in the context of both inheritance and evolutionary change.


Characteristics of life All living things on Earth are descended from a

common ancestor Evolution- We know that living things change over time

and that life forms have existed on earth for over 3.5 billion years. In evaluating life forms which existed long ago, we note that the farther back in time we go, the less similar life forms were to present forms. Biologists have concluded that all life forms are interrelated. Our view of the unity of life considers existing life forms as representing the tips of the branches of a tree; branch points represent common ancestors which subsequently diverged into separate groups to yield the branch tips. Evidence supporting the idea of interrelatedness has been obtained from numerous areas of inquiry.


Phylogenetic Tree



Some additional attributes of life: The cell is the lowest level of organization

capable of performing all of the activities of life. Hence, cells are the basic structural and functional units of life- they are alive.

Structure is correlated with function. The requirement for energy is a universal

attribute of life because all of life's processes involve work.



A physical system will be said to be "alive" if it displays three properties:

1. Reproductive capacity.2. Autonomous morphogenesis- it is built through inner processes

(as opposed to a machine, built through processes "controlled from outside").

3. Teleonomy- it is capable of behavior, which is observed to be "adapted to an end".

A crystal meets points 1 and 2, but not 3.

A machine meets point 3, but generally not 1 nor 2. Robots which would have a

possibility to build other similar robots in a factory, would meet points 1 and 3 but not 2. Note that every robot thus built would be formed through forces, "controlled from outside" and would therefore not be "alive".


How many species are there? This is not an easy question to answer. About 1 3/4 million have

been given scientific names. Nearly 2/3 of these are insects. Estimates of the total number of living species generally range from 10 to 100 million. It is likely the actual number is on the order of 13 to 14 million, with most being insects and microscopic life forms in tropical regions. However, we may never know how many there are because many of them will become extinct before being counted and described.

The tremendous diversity in life today is not new to our planet. The noted paleontologist Stephen Jay Gould estimated that 99% of all plant and animal species that have existed have already become extinct with most leaving no fossils. It is also humbling to realize that humans and other large animals are freakishly rare life forms, since 99% of all known animal species are smaller than bumble bees.


How many species are there?

(53%)

(2.2%)

(20%)

(0.07%)

(4.9%) (1.9%)

(17.5%)

(0.34%)


THE HISTORY OF THE AMAZING SCARAB BEETLES

A dung beetle called 'Aksak' was supposed to have made the first woman and man on earth from clay. In ancient China, a Taoist text quotes "the Scarab rolls its pellet, and life is born in it as an effect nondispersed work spiritual concentration. Now, even in manure an embryo can develop and cast his 'terrestrial' skins, why should the dwelling of celestial hearts not be able to generate a body to, if we put our spirit on it?"

Scarab Beetles can be found in South America and Egypt. The dung beetle fossils date back 40 million years. The Egyptians immortalized the scarab beetle as sacred. The Egyptians believed that the scarab beetle represented their sun god, Ra. Ra was the Egyptian god who rolled the sun across the sky and buried it each night. The scarab beetle became so sacred that they were put on unique stones to wear as jewelry. Archaeologists have also uncovered some evidence that Indians tribes in South America also viewed the scarab beetle religious symbol.

http://video.nationalgeographic.com/video/player/animals/reptiles-animals/lizards/flying_reptiles.html...

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