Living World-1 Flashcards
what is biology?
bios=life
logos=study
it is the story of life on earth
it is the science of life forms and living organisms
it is study of evolution of organisms on earth.
what is taxonomy
Anthropocentric approach to biology did not lead to much succes its main aim was human life .
Systematic and monumental description of life forms made human to
make a detailed system of identification, nomenclature and classification
of organisms i.e. Taxonomy
how are organisms related
All the organisms have been evolved by a very long and complex
process of evolution, so they all are related to each other by sharing of
some common genetic material but upto varying degrees.
what are characters defining living
non defining:
growth
reproduction
defining:
ability to sense and respond- consciousness
metabolism
self organise and interact(cellular organisation)
alll living organisms grow. give reason
Increase in mass and increase in number of individuals are twin
characters of growth.
different types of growth
indeterminate:
- organisms grows continuouslt lifelong.
-plants keep growing lifelong due to cell division in meristamatic cells. it is localised growth
determinate growth:
-organism grows only to a certain age, and then cell divison to replace old and worn out cells
-in animals( diffused growth)
in microorganisms, cells grow by cell division.this can be observed in ‘in vitro cultures’
intrinsi and extrinsic growth:
inntrinsic growth- growth occurs from inside in living orgs
extrinsic- growth occurs from outside in non living organisms. in mountains the no living materials depositsi on surface
what is reproduction? is it a deifning feature of life? why?
production of new progeny by a living organism possessing similar features to parents.
-> for unicellular organisms like amoeba and certain algae, growth and cell division are equivalent.
-> many living organisms do not reproduce for example, mule( hybrid of donkey and horse), worker bees( sterile female), infertile human coouple
so it is not defining feature of life
how do these organisms reproduce:
i) fungi
ii) fungi, protonema of mosses, filamentour algae,planaria
i) production of millions of asexual spores
ii) fragementation
what is metabolism
The sum total of all metabolic reactiosn occuring in the living system is metabolism. These reactions involve conversions and biochemical reacns.
catabolism= reduction reactions
anabolism=production reactions
catabolism<anabolism=+ve grwoth
catabolism>anabolism= -ve growth
catabolism= anabolism= death
all living organisms exhibit metabolism. it is a defining feature of growth
what ab reactions in test tube
The isolated metabolic reaction outside the body of an organism,
performed in a test tube (in-vitro) is neither living nor non living.
*These isolated reactions can not be regarded as living things, but they
are definitely living reactions because they are similar to the
reactions performing in our body.
what is consciousness?
ability to sense surroundings and respond to envirionemtnal stimuli which maybe chemical, physical or biological
All organisms from the prokaryotes to complex eukaryotes show
consciousness to environmental cues.
*Plants also sense and respond to external factors like light, water,
temperature, other organisms, pollutants etc.
Plants perform flowering in a particular season (photoperiodism)
*Some animals perform breeding in a particular season only (seasonal
breeders)
what is self- consciousness
When human is concerned a very high level of consciousness is found
in human because of our very well developed nervous system and
supreme level of skill of communication which is called self-
consciousness.
*Self-consciousness is thought to be present only in human.
*The brain dead coma patient who is supported by machines which
replace heart and lungs also has consciousness
*So it is living but it does not has self consciousness because it has lost
the co-ordination of organs of different body parts.
define living organism
Properties of tissues are not present in the constituent cells but arise
as a result of interactions among the constituent cells.
*Similarly, properties of cellular organelles are not present in the
molecular constituents of the organelle but arise as a result of
interactions among the molecular components comprising the
organelle.
*All the living phenomena are due to underlying interactions between
different components of an individual or organ or tissue or cell.
*Living organisms are self replicating, evolving, and self regulating
interactive system capable of responding to external stimuli.
Adaptations and homeostasis( thermoregulation and osmoregulation) are also very important characters of
livings.
