Evolutionary bio final

A random component of evolution

Genetic drift; Genetic drift is considered random because it relies on processes that cannot be predicted such as earthquakes and volcano explosions. The effect of genetic drift is felt more by small populations, as more of their gene pool is lost and many of the allele possibilities are lost due to either a bottle neck or due to the founders effect.

A non random component of evolution

Natural selection; Natural selection is non-random because it relies on the fitness of the individual. The more fit and the better the traits an organism has, the more likely they are to survive and reproduce, making it non-random process.

What are the misconceptions of evolution

• Evolution is just a theory

• Evolution is natural selection

• Evolution is entirely random

• Evolution violates the end law of termaldynamics

• Evolution is a bunch of progress

• simple to complex evolution

Scientific ideas

Hypothesis: A statement of what may be true

facts: Hypothesis can be referred to as FACTS if there is a lot of evidence for scientists to assume its true.

theories: A set of ideas passed on reasoning and evidence based on hypothesis that explain a variety of observations.

Evolution is Falsifiable [T or F]

True- the idea that god exists is not falsfiable, but evolution is through things like fossils that show absolute certainty.

Theory of Evolution

There are 2 meanings of evolution:

-fact of evolution:heritable change over time

-theory of evolution: mechanisms of evolution

Definition of science

A body of knowledge about the natural world as well as the process of generating the knowledge by observations

The chain of being (GCB) -Pre-Darwinism views

1500-1700;

-Gods plan of creation

-from inanimate objects like rocks to animate forms of life up through ever “higher” forms

-Perfect, complete with no gaps

-everything is perfect and not changing

-No change over time: has fixed identities (species)

Carl Linnaeus

Father of modern taxonomy

George Cuvier

Father of paleontology

-found fossils of species that no longer exist (mastodons and mammoths)

-found “gaps” in the great chain of being

evolution is a two step process that involves:

generation and heritable variation

sorting can be divided into two processes:

-Selection: Nonrandom sorting via the differences in the ability to survive and reproduce (fitness)

-Random genetic drift: random sorting of variance due to chance effects; only finite populations are susceptible to evolution by drift

Contradicting data against pre-darwinian views of biodiversity:

• Extinction: Fossils proved gaps in the GCB, god is no longer perfect.

• Uniformitarianism: Came about through the questioning of catastrophism- Hutton and Lyell questioned the age of the earth.

  -Natural laws to NOT change over time or space

• Diversity as a product change over time: Lammarks theories of evolution

Hutton

Father of Geology

calculating sediment deposition to determine fossils

Earth is much older

-ex: 100 m between two clams; rate of deposition= 0.02m/yr ; 100m/0.02 m/yr= 5,000 yrs

Lamarck

• Theory of organic progression:

  -New species originate through spontaneous generation (no common ancestry) simple-complex

  -Problems: no extinction and no common ancestry

• transformational theory of evolution by: inheritance of acquired characteristics:

  -new and heritable traits were developed through an organisms life span and can be acquired through use or environment

• -the unit was the INDIVIDUAL

• impossible because somatic changes are not heritable

Darwin-Theory of descent w/ modification

-extinctions are common

-different species share common ancestry

Wallace and Darwin- Variational/ population theory of evolution by natural selection

-The frequency of genetically distinct variants in a pop. change over time due to differential fitness.

The unit of evolution is the

Population

The unit of selection is the

individual

If organisms have fundamental similarities then there is—-

If there are fundamental differences then there is——-

common ancestry

separate origins

Evidence of evolution:

• Comparative anatomy

• Universal genetic code

• The universal cell membrane

• Molecular sequence data

• eukaryotic organelles

Homology definition

similarity due to common ancestry

Darwins theory of descent w/ modification

VESTIGES VS ANTAVISMS

• Vestiges: Evolutionary remnants of species that were previously adaptations, ancestrally, but are not either.

  -Traits become vestigial when they no longer perform the function they were evolved for

• Atavisms: The sporadic expression of an ancestral trait due to the misfiring of an ancestral, (uaually) suppressed, '“developmental program”

Conditions of evolution by natural selection:

-variation in a pop.

-heritability to carry variations

-differential fitness of variants

Convergent evolution

distantly related organisms independently evolve similar traits to adapt similar necessities

ex. wings in insects and birds

adaptive radiation

rapid increase in # of species w/ common ancestor; characterized by great ecological and morphological diversity

ex. oceanic islands that were never connected to a continent

Homologous vs convergence

• A homologous traits is present in the common ancestor of two taxa

• A trait is convergent if it is not present in the common ancestor of two taxa

Three types of selection

Directional: trait moves in one direction →

Stabalizing: # of intermediate values increase →←

Disruptive:Bimodal ←→

Random/lawfulness

Random: random ‘indifference’ of mutation process

Lawfulness: orders and filters the variation, keeping individuals better adapted

Differential fitness of varients

When this depends on environment it is natural selection.

When it depends on selective breeding it is artificial selection.

What are stromatolites?

Mats of cyanobacteria- their fossils are the oldest for living organisms

What organism was the oldest known eukaryotic fossil?

Grypania

What extant group does bangiomorpha resemble?

Bangia- red algae

What primarily introduces genetic variation

Mutation

What distributes genetic variation

Recombination and independent assortment

synonymous mutations:

Change the nucleotide but dont change the amino acid the codon codes for

What are the assumptions of HWE?

-no mutation

-no migration

-no selection

-no drift

-infinite pop size

are deleterious mutations able to fixate?

yes

What was the largest mass extinction event in earths history

the permian

Name the 5 mass extinction ( in order)

Ordovician, devonian, permian, triassic, cretaceous