kjyworld.blog

Properties of Life-Part 1 & II

The difference between postulates and laws

A postulate is a theory that is not yet proven, while laws are largely accepted by the scientific community as true (they have already been tested)

Principle: fundamental truth that acts as the foundation for a system/belief/behavior

Discovery science → exploring and finding new things

Hypothesis-driven science → starting with an observation, then asking scientific questions about said observation

homeostasis 
Warm-blooded animals regulate body temperature with internal methods. Cold-blooded animals use external sources.

features of living things

1) organisms adapt to their environment to survive and regulate their body processes accordingly.
2) organisms have a natural tendency to retain homeostasis3) growth and development (dictated by DNA)
4) organisms respond to stimuli
5) organisms take in energy and converts it to something (often heat)
6) reproduction
7) organisms evolve constantly.

Broad Classification of Life

A species is a group of organisms that live in the same place and time and are able to reproduce among themselves.

One of the significant properties to define if an organism/organisms belongs to a species is whether or not they can reproduce among themselves.

Taxonomy is the branch of biology which deals with classification of organisms.

The three domains of life are bacteria, archaea and eukarya. Bacteria and archaea are prokaryotes, whereas eukarya includes all eukaryotes.

Bacteria
Not all bacteria are harmful. In fact, many bacteria are useful and we wouldn’t survive without them. Bacteria are used in various biotechnological applications, one example being the RT-PCR test (COVID-19 test). Cyanobacteria are photosynthetic bacteria found in freshwater, marine, and terrestrial environments worldwide. Plants and cyanobacteria play a major role in releasing the oxygen to the planet.

Archaea
Both bacteria and archaea are prokaryotes. However, archaea are similar to bacteria but evolutionarily distinct, thus having a separate domain of their own. Some examples include halophiles (those who inhabit extremely salty environments), methanogens (those who produce methane) and thermophiles (those who inhabit scorching environments).

Eukarya
Eukarya includes all eukaryotes, which are fungi (mushrooms, molds, yeast), plantae (plants), and animalia, which splits into two groups (invertebrates and vertebrates). The fourth group is protista and includes eukaryotic organisms that are not part of the other groups such as amoeba.

Overview of Major Themes in Biology

The five major themes in biology are: Evolution, relationship between structure and function, information flow from DNA to proteins, the energy transformations, and interconnections within systems.

Evolution
Natural selection is the core theme of evolution as it occurs at all levels of the ecosystem. All living organisms are subjected to evolution.

Relationship Between Structure and Function
The structure is very important in order for (ex: organs) to function properly. This can be seen in sickle cell anemia, where the structure of hemoglobin has been disrupted and results in sickle-shaped red blood cells which are less efficient than normal blood cells.

Information Flow from DNA to Proteins
Information flow is extremely important because all life’s existence, growth, development, and evolution is determined by its genetic material.

Energy Transformation 
“Remember, if we had the ability to do photosynthesis, ​none of you would have taken ​this course because you don’t need a job. “

All biological systems depend on obtaining, converting, and releasing energy in order to survive. The same goes for matter. Everything gets converted to something or the other constantly as organisms eat and get eaten. Energy transformation is involved in all these processes. Some examples are cellular respiration and photosynthesis. Cellular respiration is involved in organisms where ATP is generated and is the source of energy for all cellular activities. Photosynthesis makes use of sunlight to generate glucose in plants, etc.

Interconnections Within Systems 
All systems are interconnected because they’re not separated as isolated entities. Anything which affects another area/region/species can spread to our environment and impact our survival.

Knowing the properties of life are essential when evaluating whether something is living or nonliving. I previously had limited knowledge on the classifications of living things, so the three domains of life (Archaea, Eukarya, Bacteria) added a layer of complexity. I found the overview in major themes of biology very interesting because they were all concepts that provide explanations and deeper insight into living things. I was able to link CR (cellular respiration) with energy transformation with how it’s involved in organisms where ATP is generated and is the source of energy for all cellular activities.