Chapter Two Notes<\/p>\n
Big Ideas in Biology: Change with Time<\/p>\n
What is the significance of a change with time? How do we define evolution? What are some patterns of evolution and how can we prove that a change actually occurred. How are species formed or changed with time? These are the primary questions in chapter two.<\/p>\n
Evolution is:<\/p>\n
an explanation for the increase in biological diversity.
\na theory that describes how current species are descendants of species of previous generations.
\nis a process by which populations show change (gradual or punctual) over several generations.
\na basic definition of evolution is a gradual change of species with time.
\nFirst of all, a change within a species of organisms can be noted by a change in structure, habitat or even behaviour. This change can be refered to as an adaption.<\/p>\n
When is a population of organisms considered to be adapted to it\u2019s environment?<\/p>\n
( this is a great question to remember..)<\/p>\n
Even though the environment may change to a small degree, successive generations of offspring thrive.
\nThe most desirable adaptations are those which give an organism a advantage to survive.<\/p>\n
A way of showing a longer duration of change with time is to examine remnants of previous generations. These remnants can be actual bones or imprints of organisms. This preserved bits of structural or imprinted information are refered to as fossils.<\/p>\n
Fossil records provide the most direct evidence of evolution
\nMost fossils are found in sandstone and limestone.
\nProblems with fossils:
\nThere are gaps in fossil records<\/p>\n
due to movement of the earth
\nno know record of organism in that time period
\none organism eating another at one location and then depositing the remnant at another location
\nSome specimens are not complete organisms<\/p>\n
The process of fossilization requires a specific type of soil<\/p>\n
Some specimens are too soft to make a fossil<\/p>\n
for example a shelled organism would make a better imprint than a worm)
\nWith the advent of genetic research and cell biology, there are now new ways to establish indirect proof of a change with time:<\/p>\n
Embryology:
\nExamining the stages of development of an embryo in a variety of species, there appears to be some similarities. This similarity was noted by \u2026who said ” “. Basically, the development of an embryo shows the species phylogenic or family history.
\n2. Examining structures<\/p>\n
There are three terms relative to structures that are useful for comparing species.<\/p>\n
This table may be helpful for comparing homologous to analogous structures.<\/p>\n
Structure type and example<\/p>\n
Structure<\/p>\n
Function<\/p>\n
Homologous<\/p>\n
similar<\/p>\n
different<\/p>\n
Analogous<\/p>\n
different<\/p>\n
similar<\/p>\n
Vestigial<\/p>\n
present<\/p>\n
no function<\/p>\n
Physiology
\nBiochemistry
\nPattern of Evolutions:<\/p>\n
Convergence<\/p>\n
If an organisms develops similar structures due to living in similar environments but they are separated due to being geographically isolated, this is an example of convergent evolution. Basically two distinct species show a similarity, although they are not genetically link. The term converge means to come together.<\/p>\n
Divergence<\/p>\n
Sources of change<\/p>\n
The concept of speciation<\/p>\n
The term “speciation” refers to the formation of new species. New species are formed when one population of the same species is separated from another and there is no exhange of genetic information between the two populations.<\/p>\n
what can cause speciation?<\/p>\n
isolating mechanisms that may lead to speciation<\/p>\n
( remember diagram in class about sea snails)<\/p>\n
geographic
\necological
\nbehavioral
\nmorphology
\ngenetic
\nWhile many of these isolation mechanisms may be crossed. For example a snail may adapt from one ecological environment to another. The one barrier that cannot not be crossed in natural situations is the reproductive or genetic barrier.<\/p>\n","protected":false},"excerpt":{"rendered":"
Chapter Two Notes Big Ideas in Biology: Change with Time What is the significance of a change with time? How do we define evolution? What are some patterns of evolution and how can we prove that a change actually occurred. How are species formed or changed with time? These are the primary questions in chapter […]<\/p>\n","protected":false},"author":245,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-301","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/posts\/301","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/users\/245"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/comments?post=301"}],"version-history":[{"count":1,"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/posts\/301\/revisions"}],"predecessor-version":[{"id":302,"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/posts\/301\/revisions\/302"}],"wp:attachment":[{"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/media?parent=301"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/categories?post=301"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.vsb.bc.ca\/mcarmichae\/wp-json\/wp\/v2\/tags?post=301"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}