Exam (elaborations)
BIOL 225 FORM AND FUNCTION OF ORGANISMS Concordia University
- Course
- Institution
BIOL 225 FORM AND FUNCTION OF ORGANISMS Concordia University
[Show more]
Seller
Follow
smartzone
Reviews received
Content preview
BIOL 225 FORM AND FUNCTION OFORGANISMS Concordia University
Chapter 22: Descent with modification - A Darwinian view of life 06-Sep-10
biology is distinguished by genetics and evolution theory
The 3 key points of the chapter:
22.1 The Darwinian revolution challenged traditional views of a young Earth inhabited by
unchanging species (p452-455)
22.2 Descent with modification by natural selection explains the adaptations of organisms and
the unity and diversity of life (p455-460)
22.3 Evolution is supported by an overwhelming amount of scientific evidence (p460-466)
Definition of Taxonomy: a scientific discipline concerned with naming and classifying the
diverse forms of life
Linnaeus developed the two-part, or binomial, system of naming species (e.g. Homos sapiens for
humans) that is still used today. He adopted a nested classification system, grouping similar
species into increasingly general categories (i.e. similar species are grouped in the same genus,
similar genera (plural of genus) are grouped in the same family, and so on)
Lamarck's principles: (p454)
1) use and disuse: the idea that parts of the body that are used extensively become larger and
stronger, while those that are not used deteriorate. (e.g. giraffes needed long necks to reach
taller trees)
2) inheritance of acquired characterisitics: stated that an organism could pass these
modifications to its offspring. (e.g. it took several generations of giraffes with long necks; genes)
- Today there is no evidence that acquired characteristics can be passed down the way Lamarck
proposed.
Definition of Natural Selection: a process in which individuals with certain inherited traits leave
more offspring than individuals with other traits.
The differential reproductive success of individuals within a population based on how well those
individuals are adapted to their environment (7th ed).
Some summarizing points on Natural Selection
,- a process during which individuals with certain heritable traits survive and reproduce at a
higher rate than other individuals
- over time natural selection can increase the match between organisms and their environments
- if an environment alters or if an individual moves to a new environment, natural selection may
,result in adaptation to these new conditions, something giving rise to new species in the process
- individuals do not evolve, populations do
- natural selection can amplify or diminish only heritable traits
- environmental factors vary from place to place and over time
when a lion takes over a new area it gets rid of the baby cubs in order to stop the mother's from
lactating, thus they will begin to ovulate more and will then conceive the cubs of the lion. The
lion behaves this way in order to get rid of potential competition and also in order to make sure
that HIS genes are passed down. *survival of the fittest
difference between a small fish and a whale: fish's tale propels sideways while the whale's tail
propels upwards and downwards. WHY? Because whales used to walk on land; the vertical
column moves better up and down. The fish propels differently because it didn't walk on land.
Independant evolution caused them to evolve differently. Natural selection only edits what's
already there.
how are bat wings and bird wings both homologous and have evolved through convergent
evolution? As wings independent (mammal and bird), as forelimbs common acestor reptile
ancestors.
THE ORIGIN OF SPECIED, 1859 (Darwin): this book has had more effect on humans than relativity
or quantum mechanics
Darwin didn't want a bad reaction from people, so he avoided using the term ¨evolution¨.
Instead he only used the word ¨evolved¨
What is EVOLUTION? Change in the genetic composition of a population over time.
Darwin's Fame: His great contribution?
He first came up with a mechanism and then made it pausible with proof. (Natural Selection)
Darwin's two major points: that descent with modification explains life's unity and diversity and
that natural selection brings about the match between organisms and their environment.
1) Species were not created in their present forms but evolved from ancestral species (descent
with modification)
2) A mechanism for evolution: natural selection
- In 1858, Wallace wrote a short manuscript similar to his unpublished book.
Dissection of Darwin's theory:
O: animals vary in phenotype
, O: some variation is heritable
O: populations have the capacity to overly reproduce
O: some survive to reproduce, some die
I: those with higher reproductive success leave more offspring (hypothesis needed here) and
copies of their genes
I: genetic change within the population
Apply to cheetah's speed: Cheetahs vary in running speed (variation in some trait); some of this
variation is heritable (genes); cheetahs who run faster chatch more prey, survive better and
leave more offspring (hypothesis); within the pop of cheetahs the genes for faster running
accumulate in the pop (genetic change in the pop.
*come up with theories in which there's some sort of diminishing factor? DON'T MAKE IT
LAMARCKIAN!
Apply to blind save fish: Assumption - there isnt sufficient light for sight in caves; O: fish in caves
vary in their eye development; O: some of this variation in eye development is heritable;
hypothesis: fish with less developed eyes save energy which can be used for growth and
reproduction; I: fish with less developed eyes have higher survival and reproduction; I: genes for
less developed eyes spread in the population.
Pre-Darwinian Views:
Aristotle 384-322 BC -
Scala naturae (the ladder of life): Species can be arranged on a scale of increasing complexity
AND species do not change & have a fixed place on this ladder. (exactly the opposite of the
Darwinian view)
AKA the great chain of being
Is this ranking of life correct? No; no part of the theory of evolution; what is this ranking really
about? You can't measure complexity.
To some extent this is kind of like taxonom, there is a biology to it (i.e. we don't eat chimps since
they are related to us)
Natural Theology:
-Adaptations: evidence of the Creator's design (intelligent design)
-Analogy of the watch - William Paley(walking thru a field discover a watch, it's beautiful and it
has a function which both could tell you something that a good design implied an intelligent
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller smartzone. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $15.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
60904 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now