Organisms to Ecosystems

UCI: Organisms to Ecosystems: Midterm 1 Prep

What is Evolution?

Changes of a population of species over time.

• Resulting in New Species and Traits

What is Natural Selection?

Fundamental Mechanism of Evolution

• Advantageous species produce more offspring and survive more: compared to those with non advantageous traits

When Did the Earth Originate?

4.6 billion years ago

When was the first Evidence of Life? (origin of life)

3.6 billion Years Ago

When was the Accumulation of oxygen in the atmosphere?

2.3 billion years ago

When was the Origin of Eukaryotes?

2 Billion Years Ago

What came first? Oldest Animal Fossils or Plant Colonization?

Oldest Animal Fossils.

In What order did the Origin of Life Occur?

• Heat

• Cooled Down: H20, H2, CH4, NH3, CO2, N2

What are the 4 time periods? And in what order? What time frame were they?

1) Precambrian: 4.6 billion years ago - 541 million years ago

2) Paleozioc: 541 million years ago - 252 million years ago

3) Mesozioc: 252 million years ago - 66 million years ago

4) Cenozoic: 66 million - now

What is the Definition of Life? (5 things)

1) Life uses Energy

2) Organisms consist of cells - multicellular and singular

3) Living Organisms contain and process information (Hereditary Information)

4) Life can Replicate Itself

5) Life Evolves

What are the 4 steps of the Origin of Life?

1) Abiotic Synthesis

2) Formation of Polymers

3) Formation of Protobionts

4) The origin of Hereditary Information

Central Dogma

DNA → RNA → Protein

What was Platos Theory?

Typological Thinking:

• “True” or “Ideal” form of species that is unfixed and unchanging

Lamarck Theory

• Proposed that Organisms do change

• Species Change Gradually Overtime

• Each Species arises spontaneously

• Inheritance of Acquired Characteristics: Whatever an individual acquires during its life time will be passed to its offspring

What is Charles Theory?

• Species change over time

• 1) Steady Change: Species DO NOT stay the same

• 2) Gradualism: Change takes place gradually

• 3) Speciation: New species arise from existing species by splitting

• 4) Common Ancestry: 2 species arose from a single species

• 5) Natural Selection: Evolutional change by preferential survival and reproduction of organisms that are better adapted

What are 4 characteristics of Natural Selection?

• Variation among individuals

• Variation is inheritable

• Species produce more offspring than can survive

• Differential Reproductive Success

What is Fitness?

Ability of an individual to produce surviving fertile offspring compared to another who cant

What is Adaption?

Heritable trait that increases fitness of an individual relative to another individual that lacks trait

What is Directional Selection? What happens to Genetic Variation?

Average traits changes direction - shifts to one side of spectrum

Genetic Variation is reduced

What is Stabilizing Selection? What happens to Genetic Variation?

Average phenotypes are favored: extremities are removed

Genetic Variation is Decreased

What is Disruptive Selection? What happens to Genetic Variation?

Sexual Selection

Selection that acts on organisms ability to mate and reproduce

What is Fundamental Asymmetry Of Sex?

difference in reproductive strategies and investment between males and females in most sexually reproducing species

What is Intersexual Selection?

Female Choice

What is Intrasexual Selection?

Male vs Male Competition for females and territory

What is the Hardy-Weinburg Principle?

What conditions need to be intact for this to work?

The theory that allele frequencies don’t change over time

No Gene Flow

No Mutation

No Genetic Drift

No Natural Selection

Random Mating

Allele

A version of a gene → diploid in most cases

Allele Frequency

The Frequency of Alleles within a population

What is Genotype? Examples?

The Genetic Makeup

A1 A1

A2 A2

A1 A2

What is Phenotype? Examples?

The physical characteristics

Black Hair, Brown

What is a Dominant allele?

A allele that dominants the other allele

What is a recessive allele?

A allele tha is dominated by the other - you can have it but it wont show if paired with a dominant allele

What is a Gene Pool?

A “pool” of alleles in a population. All alleles in a population

What is Random Mating?

Mating without preference of Genotype

What is Non Random Mating?

individuals in a population do not mate randomly, but rather mate with others based on certain traits, preferences, or behaviors.

What is Outbreeding?

Mating Between genetically different individuals → resulting in excess of heterozygotes in population

What is Inbreeding? What Increases?

Also Known as Selfing: Breeding between relatives or itself (self fertilization).

Increasing Homozygosity

What are some major affects of Inbreeding?

Increases Homozygosity → reveals harmful recessive alleles

What is Genetic Drift? Leads to what?

In which type of group does it have a bigger affect in?

What is its respect to fitness?

Random Change of Allele Frequency within a population → loss of alleles sometimes

Bigger affect on Smaller Populations

Random with Respect to fitness

What is Gene Flow?

Increases What?

Makes them More Similar or Different?

Movement of Alleles from one population to another

Gene flow increases genetic diversity

Makes populations more similar

What are Mutations?

Are they Heritable? Common or Rare? How can they Occur?

Change in DNA that occurs during DNA replication

Mutations are heritable, common, and can either occur in single based pairs or entire chromosome.

What are some Types of Mutations?

1) Neutral

2) Bad Mutations

3) Good Mutations

What are Neutral Mutations?

Respect to Fitness?

Mutations that have no effect

Neutral in Respect to Fitness

What are Bad Mutations?

Mutations that can result in poor health, low survival, or death

What are Beneficial Mutations?

Mutations that help adapt into environments, survive better, increases chances of reproduction, etc.

Favored by Natural Selection → leading to evolutionary Change

What is Speciation?

What are its 5 components?

Speciation is the multiplication of Species

1) Steady Change

2) Gradualism

3) Natural Selection

4) Multiplication of Species

5) Common Descent

What are 2 steps of Speciation?

1) Genetic Isolation

2) Genetic Divergence

• Mutation, Natural Selections, genetic Drift, etc.

What are the 3 definitions of species?

• Biological Species Complex

• Morphogenesis Complex

• Phylogenetic Complex

What is the Biological Species Concept?

species as individuals in populations that breed and produce offspring

What is Reproductive Isolation?

refers to a set of mechanisms that prevent two different species or populations from interbreeding and producing fertile offspring

What is Prezygotic Isolation?

What are the types of Prezygotic Isolations?

Mechanisms that Prevent fertilization!

• Behavioral

• Mechanical

• Gametic

• Habitat

What is Postzygotic Isolation?

After Mating: but hybrid offspring are either infertile or dead

What is the Morpho-species concept?

species defined based on its physical traits or morphology

Example) such as size, shape, color, or structure

What is the Phylogenetic Concept?

Diagram that shows evolutionary history of a group of species

What are 2 processes of Speciation?

Allopatric Speciation

Sympatric Speciation

What is Allopatric Speciation?

Occurs because of What?

Takes place in presence of geographical Isolation

• Different Habitats

Vicariance or Disposal Event

What is a Vicariance Event?

Population is Split because of a physical splitting of a habitat

What is a Dispersal Event?

Group of individuals move to another location

What are the steps for Allopatric Speciation?

1) Separation of Original Species by virariance or disperal event

2) Mutation

3) Natural Selection

4) Genetic Drift

5) Reproductive Isolation

Sympatric Speciation

Same Habitat: Absence of geological barrier

Yes they can! Its called a Ecological Niche

What is a Ecological Niche?

Why does it occur?

ecological niche is the unique role a species plays in its ecosystem, including its habitat, behavior, diet, and interactions with other species

Occurs because of Disruptive Selection

What is Internal Sympatic Speciation?

What is an Example of this?

Lies within: chromosomal mutations that cause reproductive barrier

PolyPloidy

What are 5 things that can happen if 2 species come into contact?

What does each thing mean?

1) Fusion of Population: No time for genetic change - 2 species interbreed just fine

2) Extinction: One species survives better - other dies out

3) Reinforcement: Populations come back together

4) Hybrid Zones: Regions where populations are in contact and have fertile and viable hybrids

5) Speciation: sometimes hybrid can become separate species from hybrid parents

PolyPloidy

condition in which an organism has more than two sets of chromosomes.

• Autopolyploidy

• Allopolyploidy

What is Autopolyploidy?

a condition in which an organism has more than two sets of chromosomes from the same species

What is Allopolyploidy?

a process that creates organisms with two or more sets of chromosomes from different species

Founder Effect

When a new species is established because of a smaller group of individuals from a larger population.

This small group may have a genetic makeup that is not representative of the original population, leading to reduced genetic diversity in the new population.

BottleNeck Effect

type of genetic drift that occurs when a population's size is drastically reduced due to a sudden event, such as a natural disaster, disease, or human activity.

This reduction in population size causes a loss of genetic diversity, as only a small, random sample of the original population survives to reproduce.

What are Phylogenetic Trees?

They illustrate relationships between species and how they evolved over time.

Root

Oldest part of tree

What is Node?

Common Ancestor

Branch?

Lines of the phylogeny

What is a Outgroup?

Taxon that split from a common ancestor earlier than the taxa being studied.

What is Homology?

Similar Characteristics due to common ancestry

What is Homoplasy?

Similar Characteristics that is NOT due to common ancestry.

What is Convergent Evolution?

The process where organisms independently evolve similar traits as a result of adapting to similar environments or ecological niches.

APART OF HOMOPLASY

What is a Monophyletic Group?

A group of organisms that consists of a common ancestor and ALL of its descendants.

What is a Non - Monophyletic Group?

A group of organisms that consists of a ancestor and SOME of its descendants

What are Synamorphies?

Characteristics that are derived from common ancestor.

Molecular Phylogenies

Phylogenetic Trees that are determined and organized based on the study of species molecular sequences: looking at its DNA, RNA, and Proteins.

What are 5 later predictions based on Charles Theory of Evolution?

1) Variation among species. Variation is Inheritable

2) Evidence of differential survival and reproduction

3) Common decent → molecular phylogenies

4) Anatomy and structure should indicate common ancestry

5) Transitional (Intermediate) forms in fossil record

• Example: Archeopteryx: transition between dinos and birds

6) Evidence of Extinction