Biology: Life on Earth Ch 1 4 9 11 14 24 25 26
This document includes a summary as well as class notes. It also includes important terms and definitions, graphs, and explanations.
Ch 1 Topics:
Characteristics of life
Complexity, Energy, Growth, Reproduction, Evolution, Stimuli
What is life?
...
CH 1 Introduction to life on earth
1.1 what is life?
Biology: Study of life
Characteristics of life:
Maintain organized complexity
Acquire & use materials & energy
o Plants: sun (autotrophic: “self-feeding” - make food)
o People/animals: eat & drink (heterotrophic: “other feeding” - hunt/get food)
o Energy is used to complete processes (digestive system, body temperature, brain
work)
Grow
o Need energy to grow, increase in size internally & externally (gym: increase in
blood flow grow)
Reproduce
o Asexual: 1 organism
o Sexual: 2 organisms
Evolve
o Genetic change in population
natural occurrences:
Difference amongst members
Offspring inherit differences
Ones inherited: better chance of survival
Respond to stimuli
o Receive stimuli to respond: gravity, sound, light
Plants: leave hang if need water
Humans: Low blood sugar, brain respond: sweat
Bacteria: move towards favorable conditions
Viruses: multiply, mutate (adapt), inert (cannot move/unreactive) & simple
What is life?
Organisms acquire and use materials and energy. Materials are obtained from other organisms
or the nonliving environment and are repeatedly recycled. Energy must be continuously
,captured from sunlight by photosynthetic organisms, whose bodies supply energy to all other
organisms. Organisms also show characteristics of life.
Natural selection: “Process by which organisms with certain inherited traits survive and
reproduce better than others in a given environment”
Organisms inherit certain traits, which benefit them & help reproduce & survive. This trait
becomes more common in population. (Short teeth beavers mutate: long teeth more
successful. Short teeth die out)
Evolution: “Change in DNA occurring in a population over time”
Example: Humans & technology: swiping: different shaped thumbs, extra vertebrae neck
Example: If living in smoke: to adapt: 3rd lung, extra filter lung, long nose hairs
(mutations)
Note: Genetic change is incredibly slow
Natural occurrences:
Difference amongst members
Offspring inherit differences
Ones inherited: better chance of survival
What is evolution?
Evolution is the scientific theory that modern organisms descended, with changes, from
earlier organisms. Evolutions occurs as a consequence of genetic differences, originally arising
as mutations, among members of a population, inheritance of these differences by offspring
and natural selection of the differences produced by the best adaptations to the organism’s
environment.
,How do scientist’s study life?
Scientist identify a hierarchy of levels of organization. Biology categorize organisms
according to 3 domains: archaea, bacteria and eukarya. Organisms are assigned scientific
names that identify each as a unique species within a specific genus.
Biological classification:
Domains: “Classifications of life”: 3 major groups
Bacteria (Simple, unicellular, no nucleus)
Archaea
Eukarya (complex, multicellular, has nucleus)
Eukarya: 4 kingdoms:
Protists
Plants
Fungi
Animals
Binomial system
“2 names” genus name is capitalized italicized, species name italicized
Genus: similar species (Capital & italic)
Species: can interbreed (Italic) Reason why humans ≠ monkeys)
“HOMOsapiens”
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