BIO2500 Exam 1 - Evolution

Ecology

The relationships between living organisms and their physical environment (biotic and abiotic)

Evolution

Descent with modification

True: Caterpillars eat and absorb the toxins, pigmenting them

True or False: Monarchs and their larvae are bright to warn predators of their toxicity

Darwin explained 3 broad observations in nature with N.S. - what are they?

Unity of Life, Diversity of Life, and the match between organisms and their environment

What are adaptations?

an inherited characteristic that enhances an organism's survival and reproduction in specific environments

What is an example of Microevolution?

Soapberry bug beak length decreased when feeding on an introduced plant

What is an example of Speciation?

Darwin's finches

How can we use molecular biology as evidence for evolution?

The more similar organisms are, the fewer amino acid differences in Cytochrome C protein

What is the "Hierarchical Organization of Life" as Linnaeus described it?

Organisms fall "naturally" into "groups-within-groups"

What is anatomical evidence in evolution?

Structures modified for different uses but have common ancestry

Homology

Similarity due to common ancestry

Define homologous structures and give an example

Similar structures between species; tetrapod forelimbs (human, cat, frog)

Define vestigial structures and give an example

Remnants of features that served a function in an organism's ancestors; hip bones in whales

Define analogous structures and give an example

Characteristics that are similar due to CONVERGENT evolution, not homology; sugar gliders in Australia, flying squirrels in North America

How do we use fossils as evidence for evolution?

We can see the succession of life from simple to complex

Define transitional (link) fossils and give an example

Fossils that show an intermediate state between the ancestral form and the currently observed one; Tiktaaliks have similarities between fish and early amphibian tetrapods

How do we use biogeography as evidence for evolution?

We can see similarities between organisms in many different places

Define biogeography and give an example

The geographic distribution of species; Xenarthrans (armadillos, anteaters, pangolins)

What is the Burgess Shale, and when did it happen?

The most diverse and well-preserved fossil location in the world; just after the Cambrian Explosion (525mya)

True

True or False: Fossils can tell us how animals moved or cared for their young

What two tests can be used to look at fossilized organisms?

Scanning Electron Microscopy (SEM) and CAT scans

How far back does the oldest evidence of life date back to?

3.9 billion years

Fossils can tell us about organism diets using what kind of signatures?

Carbon isotope signatures

List the three domains of life from oldest to most recent

Archaea (3.5bya); Bacteria (3.45bya); Eukarya (1.8bya)

True, oldest fossils at about 2.1mya

True or False: Multicellularity evolved independently in multiple lineages

What did the earliest animal life resemble, when did it come about, and in where?

Sponges; 650mya; Limestone in Australia and reefs

What is Ediacaran Fauna?

Diverse and unique organisms that dominated oceans from 575-535mya

What was the Cambrian Explosion?

A period of rapid radiation in which most major groups appeared in the fossil record (541mya)

What were the conditions of the Cambrian Explosion?

Mild climate, abundant reefs, fragmented and tropical land masses

True

True or False: Prokaryotes colonized terrestrial environments first

What did early plants resemble and when?

Mosses and liverworts; 475mya

When did the first terrestrial animal life occur?

480mya

What are the first terrestrial animals likely related to?

Insects and spiders

When were the first tetrapod fossils formed?

370mya

What are synapsids?

Organisms with one skull hole behind the eyes

How old are the oldest human fossils?

315000

When did birds evolve?

150mya

When did flowering plants evolve

132mya

What did insects evolve?

400mya

What sciences does modern synthesis combine?

Genetics, modern history, paleontology, and others

What is eukaryotic DNA organized into?

Chromosomes

What are homologous pairs?

Same sequence of genes

How many sets of chromosomes do humans have?

23 (46 chromosomes total); one set each from mom and dad

What is ploidy?

The number of copies of unique chromosomes in a cell

FALSE; recombination requires pairing up - this cannot happen in 3n organisms

True or False: Meiosis is possible with 3n organisms

What is found in the genome?

Coding regions of the DNA; Anything that affects the growth of the organism

What happens during transcription?

RNA creation; DNA is solid and uses a strand as a copy to make another

What "language" is transcription?

Nucleic acid language

What happens during translation?

Coding RNA into proteins; forming amino acid sequences

What "language" is translation?

Protein language

What is gene expression?

The process by which information from a gene is transformed into a product

Are introns cut out or turned into genes during transcription?

CUT OUT; they are IN THE WAY of exons

Are exons cut out or turned into genes during transcription?

Turned into genes; they code for proteins to be turned into an mRNA during translation

What is the genome made up of?

The coding region (exons) and the non-coding region (introns)

What can non-coding regions contain?

RNA genes; pseudogenes (genes that have no function now, but maybe had one in the past); Mobile genetic elements

What are transposons?

elements that can lift themselves out of the DNA sequence and insert themselves somewhere else?

What is correlated with complexity of an organism?

Amount of introns, or non-coding regions in DNA

If you viewed a non-dividing cell, what would it look like?

Cotton ball-like; each chromosome has to be in its designated spot in the nucleus or it will be expressed incorrectly

What can regulate gene expression?

Transcription factors; Histone acetylation; DNA methylation

What do transcription factors do in gene expression?

Makes more gene product available, quicker

What does histone acetylation do in gene expression?

Loosens DNA winding around histones and allows for easier transcription

What does DNA methylation do in gene expression?

Methylates genes wrapped around histones and shuts them off - no more coding

When are the 5 times gene regulation can occur?

Pre-transcriptional; Transcription; Post-transcription; Translation; Post-translation

What translates mRNA into proteins?

Ribosomes

Can exons be combined differently to create different proteins?

Yes, but the exons must stay in the same order

What are mutations?

any change in the genome

What do silent mutations do?

Codon changes but has no effect on the protein it codes for

What do missense mutations do?

The second codon changes and changes the protein it codes for

What do nonsense mutations do?

Codon changes and has a dramatic effect (stopping production)

What do 1base-pair deletion and frameshift mutations do?

Pushes other past pairs into different groups of 3 and thus codes for different amino acids

What are the 7 types of mutation?

Point; Insertion; Deletion; Inversion; Chromosome fusion; Gene duplication; Genome duplication

What do somatic body cell mutations affect, and are they heritable?

Body cells of an organism; not heritable in humans but often in plants, protists, and fungi

What do germ-line mutations affect, and are they heritable?

Gametes; heritable and relevant to evolution in plants, fungi, and animals

What is microRNA, and can it affect phenotypes?

Small, highly conserved noncoding RNA molecules that are involved in the regulation of gene expression; yes

What contributes to genetic diversity?

Recombination and Independent Assortment

What is recombination?

DNA segments are exchanged between chromosomes during crossing over (creates recombinant chromosomes)

What is independent assortment?

Random distribution of homologous pairs during meiosis

What is a genotype?

The genetic makeup of an individual

What is a phenotype?

An observable, measurable characteristic of an organism

Why do polyphenic traits occur?

Multiple phenotypes can be produced by a single genotype

What is phenotypic plasticity?

Drastic changes in appearance based on surroundings (common in plants)

What is a phylogeny?

A visual representation of the evolutionary history of a species or genes

What are monophyletic groups?

Taxonomic units that include the common ancestor and all of its descendants

What are synapomorphies?

Characteristics that are present in an ancestor AND shared by its descendants

What are homoplasies?

Character state similarity NOT due to common descent

What is convergent evolution?

One trait evolves multiple times due to similar selections

What are evolutionary reversals?

Reversion back to an ancestral character state

What is parsimony?

Given a set of possibilities, the simplest scientific explanation is most likely correct

What are Coelacanths?

One of the closest living relatives of tetrapods

What is coalescence of alleles in a population?

When the alleles come together to form one whole to a common ancestor

What is maximum parsimony?

The simplest explanation formed

What is a distance matrix?

Clustered taxa based on genetic distance

What is maximum likelihood?

Finding the most likely tree given molecular evolution

What are bayesian methods to building a phylogeny?

Looking at the PROBABILITY that a tree is correct given molecular evolution

Alleles are the same

Homozygous

Alleles are different

Heterozygous

What are alleles?

Varieties of versions of a gene

What is a locus?

A specific location on a chromosome

What is (micro)evolution?

Change in allele frequencies from one generation to the next

What Is population genetics?

The study of genetic compositions of populations, including genotype and phenotype changes