BIO EXAM 1

Who wrote the origin of species and what is the significance of the book?

Charles Darwin. launched the era of evolution theory

Plato

All species have a perfect form, species variation is an imperfection of that form

Aristotle

Saw that organisms vary in complexity and can be arranged based on their order of increasing complexity

Count Buffon

Wrote plants and animals. Suggested Environmental influences the struggle for existence

Carolus Linnaeus

Believed each species had an ideal structure, and a place in the scala naturae (sequential ladder of life)

Erasmus Darwin

Proposed that species change overtime

Georges Cuvier

proposed a new assembly of species moves into an area after mastic extinction events (catastrophism)

Jean-Baptiste Lamark

Proposed that physical changes that are aquired by an organism during its lifetime are passed onto its offspring (The inheritance of acquired characteristics)

Charles Lyell

Propose that the Earth today is shaped by the same slow natural process that shaped it in the past (uniformitarianism)

Thomas Malthus

proposed the human population is growing at an exponential rate, but Limited food, water and shelter keep this growth in check.

Charles darwin observations

Observations led him to conclude EARTH IS OLD, LIVING FORMS COULD BE FROM EXTINCT FORMs…SPECIES ARE NOT FIXED INSTEAD THEY CHANGE OVER TIME

How did the process of artificial selection influence Darwin’s development of the idea of natural selection

If artificial selection can bring lots of changes within a short period of time, then natural selection could modify species over hundreds of years

Evidence that darwin gathered from fossils and biogeography tht supported the idea of shared ancestry

Fossils:

Marine shells high in cliffs —> earth is very old and living could have decent from extinct forms

Biogeography:

Similar environments, similar looking animals..(south america —> patagonian cavy, europe —> european rabbit)

Summarize the process of evolution by natural selection

1. Organisms has heritable variation

2. Organisms competes for recources

3. Organisms differ in reproduction success (Fitness)

4. Organisms becomes adapt

What observations provide the basis for natural selection

Heritable variation (possess different traits that can be passed down)

Competition (food, shelter, water)

Reproductive success (better traits = better survival and reproduction

What is the significance of transitional fossils

Transitional fossils are a common ancestor for two difference groups of organisms..Allows us to trace the descent of organisms

Describe the fossil record

Evolution over millions of years engraved in the order of fossils that appear in rocks.

Examples of transitional fossils (3)

Archaeopteryx:

In between birds and reptiles

Tiktaalik:

“Fishapod

Ambulocetus:

Whale with legs

interpret one example from each of the four areas of study - fossil, anatomical, biographical, and biochemical - as evidence supporting the descent of all life from a common ancestor.

Fossil:

Transitional fossils (tiktaalik)

Anatomical:

Pentadactyl limbs (share same basic bone structure)

Biogeographical:

Marsupials in south america, and Australia

Biochemical:

All living organisms use same DNA triplet code

What are some of the misconceptions of evolution proposed by critics of evolution?

“ Evolution Is not observable or testable; thus is not science”

“ there are no transitional fossils”

What is a gene pool

Total alleles of all the individuals in a population

What is a population

Group of organisms of a single species living in the same area

Genetic variation

Difference in DNA and phenotypic expression

Microevolution

Change in gene frequency between a population of species overtime

5 conditions required for a population to be in Hardy Weinberg equilibrium

1. No mutations = no allelic changes

2. No migraines = no gene flow

3. A large gene pool = no genetic drift

4. Random mating

5. No selection

What is the Hardy weinburg equation?

p² + 2pq + q²

What does each Variable stand for in the hardy Weinberg equation

p = homozygous dominant

pq = Heterozygous

q = homozygous recessive

What is the significance of the hardy Weinberg equilibrium to natural populations?

It is like a speedometer for evolution. If a population does not match the equilibrium Evolution is actively happening.

Five main causes of evolutionary change

1. Natural selection

2. Mutations

3. Gene flow

4. No Random mating

5. Genetic drift

What is genetic drift?

Changes in alle frequencies of a population due to change rather than selection by the environment

Two types of genetic drift

Bottleneck effect:

severe reduction in population due to natural disasters, predation , or habitat reduction

Founder effect:

Few individuals break away from large population to found a new population (Higher chances of inbreeding)

How does natural selection consistently lead to adaptive evolution?

Favors the variant that is most adapted to the present environmental conditions

Stabilizing selection

Favors intermediate phenotypes(grey mouse over white or black)…The peak of the curve increases and tail decrease

Directional selection

Favors one extreme phenotype(Long neck, giraffe)… Curve shifts in One Direction

Disruptive selection

Favorites two or more extreme phenotypes over the intermediate phenotype(Black and white moths over grey)… The curve has two peaks

What is sexual selection?

Adaptive changes in males and females that increase the ability to secure a mate

How does sexual selection drive adaptation for increased fitness?

Males:

Increased ability to compete with other males to mate

Females:

Select a male with best fitness

Why is heterozygote advantage a form of stabilizing selection?

Shelters recessive alleles from selection..

What are two examples of heterozygote advantage?

Sickle cell disease

Cystic fibrosis

Macroevolution

Evolution on a large scale

Involves origin of species

Microevolution

Small shift in allele frequency in a single population over a short time

What is taxonomy

The process of Identifying, naming, and classifying species

Who is the founder of taxonomy?

Carolus Linnaeus

The four species concepts

1. Morphological

2. Evolutionary

3. Phylogenetic

4. Biological

Morphological species concept

Identify species based on diagnostic traits

Advantage: Can be used on asexual organisms and fossils

Disadvantage: relies on subjective criteria, Researchers may disagree on what features distinguish a species

Evolutionary species concept

Identify species based on structural traits

Advantage: Explains specialization in the fossil record

Disadvantage: requires members in a species that share a special evolutionary pathway

Phylogenetic species concept

Identify species based on common ancestor

Biological species concept

Identify species based on reproductive isolation (behavioral)

Advantage: For similar looking species that reproduce with one another

Disadvantage: Asexual and hybrids (mule)

What is a zygote?

Cell formed when sperm and egg meet

Five types of prezygotic barriers

1. Habitat isolation

2. Temporal isolation

3. Behavioral isolation

4. Mechanical isolation

5. Gametic isolation

Habitat isolation

Certain place

Temporal isolation

Different Times a day/season

Behavioral isolation

Mating dances

Mechanical isolation

Physically incompatible

Gametic Isolation

Molecular and compatibility Of eggs and speem

Two types of postzygotic isolation

Hybrid inability

Hybrid sterility

Hybrid inability

Impaired hybrid development or survival

Hybrid sterility

Cannot produce offspring

What is speciation?

Splitting of one species into two

Two modes of speciation

Allopatric speciation

Sympatric species

Allopatric speciation

New species from populations that are geographically separated

Sympatric speciation

New species from reproductively isolated groups that are not geographically isolated

What is adaptive radiation?

Rapid evolution of several species from a common ancestor

Example of adaptive radiation

Darwin’s finches

Big beak → seeds

Small beak → insects

Homologous structures

Similar structure from common ancestor

Example:

Butterfly and moth

Analogous structure

Similar function Different origin

Example:

Bird wing and bat wing

What is the process of convergent evolution?

Unrelated species develop similar traits bc they live in similar environments or face the same challenges

Distinguish between the gradualistic and the punctuated equilibrium models of evolution

gradualistic equilibrium is a gradual change that results in two separate species, punctual equilibrium is not gradual change, species appear suddenly

how does gene expression influence the process of speciation

drives phenotypic divergence and reproduction barriers or influences development?

examples of developmental genes

Pax6 (eye formation)

Tbx5 (limb buds)

Hox (number and appearance of repeating structures)

PitX1 (hind limbs)

how is macroevolution or natural selection is not goal-oriented?

it is opportunistic, enables a population with an advantage to have more offspring

What is LUCA

last universal common ancestor

what were the early earth conditions?

little oxygen, volcanic activity, lightning

what is the Oparin-Haldane hypothesis?

Conditions on early earth could have generated organic molecules

Who tested the Oparin-Haldane hypothesis and how?

stanley miller, built and apparatus mimicking the conditions of early earth