Transcript Evolution by natural selection is a major aspect

The Definition:
Biological evolution, simply put, is descent with modification.
This definition encompasses small-scale evolution (changes
in gene frequency in a population from one generation to the
next) and large-scale evolution (the descent of different
species from a common ancestor over many generations).
Evolution helps us to understand the history of life
Evolution by natural selection is a major aspect of Biology.
1. Physical factors affect life. They affect both whether an organism can
live, how it lives, and how it reproduces. These factors include…
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gravity
climate (temperature & rainfall)
Time
Light
latitude and so on.
2. Living factors affect life. They affect both whether an organism can
live, how it lives, and how it reproduces. These factors include…
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food (energy) available
Predation
Biomes
habitats.
Over periods of time, those physical and living factors change.
Acquired Traits or Inherited Traits?
(Cross Breeding)
Humans Select those
variations that they found
useful
Key Concepts of Natural Selection
A population of organisms produce more
offspring than can survive
That population of organisms has
variations of structures and behaviors
Only those organisms that are best
suited for the environment survive and
reproduce (pass of genes to the next
generation)
Overtime, all organisms of a population
will have those structures which are best
suited for that environment
Direct Observations
•Bacterial Resistance to
Antibiotics
•Peppered Moth in
Industrial England
•Darwin's Finches in the
Gallapagos Islands
Fossil Record
Adaptations (structural and
behavioral)
Homologous Structures
Embryology
Biochemistry
Vestigial Structures
Orchids fool wasps into
“mating” with them.
Katydids have camouflage
to look like leaves.
Non-poisonous king snakes
mimic poisonous coral
snakes.