Bio94 UCI

Conditions of Natural Selection

Heritable variation in populations

Some traits incresase reproductive success

Observational studies cannot conclude _____.

causation

Natural selection affects ____.

individuals

Evolutionary change affects ____.

populations

Lamarck evolutionary theory

Change occurs via acquired traits (parent to offspring)

Darwin (and Wallace) evolutionary theory

Species change through time and species are related by a common ancestor

Transitional features

An intermediate trait between older and younger species

Vestigal traits

Reduced/incompletely developed trait with no/reduced function but similar to ancestoral traits

Homology

Similar traits due to a common ancestor

Homoplasy

Similar traits but no common ancestor

Trade-offs

Compromise between two traits that can not be optimized simutaneously

Darwin’s four postulates for evolutinoary process

1. Population variation

2. Heritable traits

3. Survival and reproductive success are variable

4. Survival is not random

Hardy-Weinberg Equilibrium assumes ____.

no gene flow, no natural selection, no mutations, a large population, and completely random mating

In inbred communities, the frequency of homozygotes increases/decreases, yet frequency of alleles does/does not change.

increases, does not

The Hardy-Weinberg equilibrium is used to ____.

determine if a population is evolving, predict what will happen in the next generation, develop testable hypotheses about evolution, and estimate frequency of homozygotes and heterozygotes.

Intersexual selection

Female choosing the male

Intrasexual selection

Males competing against other males

Genetic drift

Change in allele frequency of a population due to chance

Concepts of genetic drift

1. Random

2. Smaller populations are more affected

   1. May lead to a loss (frequency=0) or fixation (frequency=1) of an allele

Causes of genetic drift

Founder effect and bottleneck

Founder effect

Some individuals leave

Bottleneck

Natural disasters

Gene flow

Movement of alleles from different populations due to migrations

Types of mutations

Point mutations (amino acids) and chromosomal mutations (protein misfolding)

Lateral gene transfer

The passing of genes through routes other than parent-offspring (common in bacteria, rare in animals and plants)

Bacterial conjugation

Attaching to other bacteria and transferring plasmids

Bacterial transformation

Collecting genetic information from a bursted bacteria

Bacterial transduction

Transfer of genetic material through viruses/bacteriophages

Note

Mutations are random so, for example, in different strains of E.coli, even if they go through the same process some strains may produce more mutations than others.

Speciation

Splitting event that creates two or more distinct species from an ancestoral species

Genetic isolation

Barrier to gene flow causes isolation of a population

Genetic divergence

Mutation, natural selection, or genetic drift in an isolated population

Biological species

Speciation based on reproductive ability

Morphological species

Speciation based on physical characteristics

Phylogentic species

Speciation based on the phylogentic tree

Prezygotic isolation

Mating does not occur due to temporal (different mating seasons), habitat, and behavioral (different courting) reasons.

OR

Mating does occur but no zygote is produced because male and female reproductive structure is incompatible or sperm and egg are incompatible.

Postzygotic isolation

A zygote is produced but it is inviable (does not develop normally and dies early) or is sterile (cannot produce offspring).

Allopatry

Populations that live in different areas

Disperal

Movement of individuals from one place to another

Vicariance

Physical splitting of a habitat

Sympatry

Populations living in the same geographic area (close enough to interbreed)

Sympatric Speciation

Mating becomes nonrandom and genetics diverge

Extrinsic events

Disruptive selection (ex. different niches or mate preference)

Intrinsic events

Chromosomal mutations

Polyploidy

Condition of having more than two complete sets of chromosomes

Autopolyploid

More than two identical sets of chromosomes

Allopolyploid

More than two different (one from mom other from dad) sets of chromosomes

Monophyletic

All species are connected by one common ancestor/synapomorphies

Paraphyletic

Leaving out one species

Polyphyletic

One or more species that have a trait in common but evolved it independently

Precambrian

1. Origin of life

2. Origin of photosynthesis (and O2 production)

3. Origin of eukaryotes

   1. Origin of multicellular animals

Adaptive radiation

Rapid production of new species

Cenozoic

First humans

First whales

First horses

Mesozoic

First flowering plants

First placental mammals

First dinosaurs

First mammals

First amniotes

Paleozoic

First fungi

First land plants

First arthopods and molluscs

First tetrapods

First seed plants

Mass extinction

Rapid extinction of a large number of a diverse species globally caused by catastrophic events (60% of the species wiped out in 1 million years)

Background extinction

The average extinction rate

Hox genes

Codes for the body map of organisms

Bacteria have a _____ while Archaea don’t.

peptidoglycan wall

Eukaryotes and Archaea share similar _____.

RNA polymerase and start codon

Both bacteria and archaea lack a _____.

Membrane bound nucleus

Gram positive

Bacteria that are stained purple and have a thick peptidoglycan layer.

Gram negative

Bacteria that appear pink and have a thin peptidoglycan layer and outer phospholipid bilayer.

Koch’s Postulates

Used to create a causative link between specific disease and microbe

1. Microbe present in infected, absent in healthy

2. Microbe can be isolated and grown in pure culture

3. Microbe from pure culture can infect a healthy individual when injected

4. The microbe can be isolated from now infected individual and is determined to be the same one

Biofilms

Bacterial colonies that have a polysaccharide shield against antibiotics

Antibiotics only work on ____.

bacteria

Phototroph

Uses light to make ATP

Chemotroph

Uses organic material to make ATP

Chemolithotroph

Uses inorganic material to make ATP

Autotroph

Self-synthesized from simple molecules (CO₂, CH₄)

Heterotroph

Carbon bonds from molecules produced by other organisms in the environment

NH₃ Pollution

NH₃ fertilizers feed bacteria who release nitrate or nitrite into the environment, often depleting oxygen content and creating dead zones.

Bioremediation

The use of bacteria or archaea to clean up sites polluted with organic solvents

Protists include all eukaryotes except _______.

land plants, animals, and fungi.

Photosynthetic protists can take atmospheric CO₂ and fix it into ____.

sugars (this may help with climate change)

Mitchondria was formed by _____.

endosymbiosis (more specifically an archaea eating an alpha proteobacteria)

Gametophyte

Multicellular haploid form

Sporophyte

Multicellular diploid form

Spores

Single haploid cells that divide through mitosis to form the gametophyte

To transition from water to land, organisms must ____.

minimize H₂O loss, resist gravity, minimize UV damage, and reproduce without water

Mosses are gametophyte/sporophyte dominant?

Gametophyte

Heterospory

Production of two distinct types of spores (megaspore and microspore) by different structures (all seed plants)

Homospory

Production of a single type of spore (all nonvascular plants and most seedless vascular plants)

Pollen grains allow land plants to _____.

reproduce without water

Fungi fix ____.

Carbon

Yeast

Unicellular fungi

Mycelium

Multicellular fungi

Hyphae

Narrow filaments that absorbs nutrients

Organismal Ecology

Morphological, physiological, and behavioral adaptations

Population Ecology

The number and distribution of individuals in a population change over time

Community Ecology

The nature and consequences of the interactions between species (predation, parasitism, competition, effects of natural disasters)

Ecosystem Ecology

How nutrients and energy move among organisms, the atmosphere, soil, and water

Global Ecology

The effects of human impact on the biosphere

Warm air is less/more dense than cold air.

less

Hadley cells explain ____.

why there deserts near 30^oN and 30^oS (dry, cold air from the equator and 60^oN/S ventilate to the deserts at 30^oN/S which in turn pick up water and disperse it back to the equator and 60^oN/S)

What does upwelling do?

Bring deep water closer to the coast (more nutrient rich water and primary productivity).

Proximate cause

How do the traits work? (pheromones, neural inputs, muscle contractions)

Ultimate causation

Why did the trait develop? (social bonds, shared resources, increased fitness)