Evolution Exam 1 Msstate

What is Biological Evolution?

○ Any change in the inherited traits of a population that occurs from one generation to the next.

What are the four key components to the Biological Evolution definition?

○ Any Change
○ Inherited traits
○ Population
○ One generation to the next

What is the goal of evolutionary biology?

○ Understand the historical perspective of how the natural world came to be

What is an ultimate explanation?

○ Focuses on historical perspective of how something came to be

What is a proximate explanation?

○ Focuses on mechanistic understanding of how something happened

What are some practical benefits to studying biological evolution?

○ Pest control
○ Antibiotics
○ Understanding disease
○ Higher crop yields
○ Understanding our history from DNA

What is an example of a cetacean

○ Whales
○ Dolphins

What traits do cetaceans share with fish

○ Streamlined bodies
○ Marine living
○ Fins

What traits do cetaceans share with mammals

○ Lungs
○ Placenta
○ Milk production
○ Hair in developing embryo
○ Live birth
○ Three inner ear bones

Are whales fish or mammals

○ Mammals
○ Evolved from terrestrial mammal through natural selection

What is natural selection

○ A mechanism that can lead to evolution, whereby differences in survival and reproduction of individuals cause some genetic types to replace others

What does darwin's hypothesis predict regarding whales

○ There will be intermediate species in the fossil record showing the transition from terrestrial mammal to whales today

What is the Dorudon (Spear tooth)

○ 40mya
○ Many whale-like structure
○ Fully aquatic
○ HAS TEETH

What is the Ambulocetus (Walking Whale)

○ 48 mya
○ Short legs and mig feet
○ Walk on land and swim like otter

What is the pakicetus (Whale of Pakistan)

○ 50mya
○ Skull and inner ear structure similar to whale
○ Fully terrestrial

What does the fossil record show about this transition

○ Gradual
○ Reduction of pelvis and hind limbs
○ Nasal opening shifts to top
○ Eyes shift to side

What can the O18/O16 ratio reveal

○ Higher ratio = in bones of marine animals
○ Ratio increases in the transition to whales in fossil record

What group of land mammals is closest related to whales

○ Artiodactyls (hippos, cows, camels)

Which artiodactyl is closest to cetaceans

○ Hippos

What is the relationship between whales and hippos

○ They share a more recent common ancestor with each other than any species of land mammals

What is the genetic regulation of hindlimb development in cetaceans

○ Hind limbs start to grow in cetacean embryos
○ After a few weeks, they degenerate due to genetic mutations that turn off the development

What is a homology

○ Shared characteristics in a group of species because they were inherited from a common ancestor
○ Ex) Shared traits between whales and mammals

What is convergent evolution

○ Shared characteristics in a group of species that evolved independently due to natural selection to similar environments
○ Ex) Shared traits between whales and fish

What is a mutation

○ Any change to the genetic material of an organism
○ They can be harmful, beneficial, or neutral

How do most mutations impact an organisms ability to survive and reproduce

○ Neutral / mildly deleterious

What is an example of a beneficial viral mutation

○ Helps evade host immune system
○ Helps hijack host immune system
○ Makes it easier to survive and reproduce

What is zoonotic transmission

○ New mutations allow for viruses to jump between hosts
○ Ex) Covid 19 and Spanish Flu

How common is zoonotic transmission

○ Not very
○ Rare to be able to jump host
○ Rarer to survive and reproduce

What are some targets for vaccines

○ Areas on a viral gene code that have not encountered lots of mutations

What are some questions that evolutionary biology can answer with virology

○ How and where did SARS-COV-2 originate from
○ How long will vaccines provide protection
○ Public health policy
○ Preventing pandemics

What are the three key aspects of the hypothetico-deductive method

○ Falsifiable hypothesis
○ Generate predictions
○ Testing predictions with observable data where result is not yet known

What are the three possible outcomes of an experiment

○ Reject hypothesis
○ Modify hypothesis
○ Provisionally accept hypothesis

Can an experiment ever prove a hypothesis is correct

○ No

What is a hypothesis

○ An informed conjecture or statement about what might be true

What is a theory

○ A comprehensive, coherent body of interconnected statements, based on evidence and reasoning, that explain some aspect of nature

What is a fact

○ A hypothesis that has endured so much testing that we act as if it is true

Is evolution a hypothesis, theory, or fact

○ ALL THREE

What were darwin's two hypotheses in Origin of Species

1. Organisms descended with modification from a common ancestor
2. The main cause of this variation is natural selection acting on hereditary variation

What is the scientific theory of evolution

○ The explanation of how modification occurs and how ancestors give rise to diverse descendents

What was the early view on diversity

○ Non-existant
○ Theory of the forms
○ Species have fixed properties

What was the great chain of being

○ Not very details
○ Fixed hierarchy of species arranged from lower to higher forms

Who was carl linneus

○ Father of taxonomy
○ His system worked because classified taxa based on shared homologies between groups
○ 1700s

What is taxonomy

○ The science of describing, naming, and classifying species

What are the taxa

○ Groups of organisms in cohesive units

Who was nicholas steno

○ Recognized fossils were once living things
○ Shark teeth arent tounge stones
○ Pioneered stratigraphy

What is stratigraphy

○ The study of layering in rocks

Who was georges cuvier

○ Pioneered paleontology
○ Discovered many mastodons and mammals
○ Fossils resemble but arent the exact same as modern species

What is paleontology

○ The study of prehistoric life

Was the idea of extinction innitially accepted

○ No, it went against ideas of European naturalist, and were hard to incorporate

Who was mary anning

○ Found fossils of many marine vertebrates that were no longer living (extinct)
○ Pioneered the idea of extinction

Who was william smith

○ British canal surveyor
○ Different rock layers contain different fauna
○ Contributed the idea that the animal makeup of an area changes over time

Who was george buffon

○ Said life emerged as distinct types but changed with the environment
○ Said earth is older than people thought based on laws of physics and chemistry

Who was jean baptiste lamark

○ Said life is driven from simple to complex
○ Believed in inheritance of acquired changes
○ Complex life comes from microbes

Who was the first to propose a correct mechanism for how life changes over time

○ Charles darwin

What was important about the voyage of the HMS Beagle

○ 5 years
○ Charles darwin collected extensive evidence in support of natural selection
○ The birds weren't different species...all on the island he saw were finches
○ Darwin sat on his ideas for 20 years

Who was alfred russel wallace

○ Independently came up with many ideas on natural selection and common ancestry similar to charles darwin

What were the two key ideas in on the origin of species

○ All species share a common ancestor
○ Changes occur through natural selection

Who was Thomas Maltheus

○ Inspired Alfred russel wallace and charles darwin
○ Wrote that the population growth of the poor exceeded the supply of the nation's food
○ Idea of a fierce struggle for survival

What are the 5 facts of natural selection

1. High birth rates predict exponential growth
2. Population sizes are normally stable
3. Natural resources are limited
4. No two individuals are exactly the same
5. Variation is heritable

What are the 3 inferences from these facts

○ Since there are more individuals born than can survive, there is a fierce struggle for existence
○ Survival depends on heritable variation
○ Over generations, heritable variation that leads to increase in survival will increase in frequency

Who was Charles Lyell

○ Published principles of geology
○ Contained idea of uniformitarianism

What is uniformitarianism

○ Idea that Earth's landscapes have been shaped over time by the cumulative processes visible today

Charles Darwin and the Weald

○ Landscape
○ Charles darwin used rates of decay that the landscape formed over the course of 300 million years
○ Earth is very old

What did lord kelvin do

○ Studied heat loss of planet to predict earth was 20 million years old
○ Incorrect because erroneous prediction about content of Earth's core

When did indisputable evidence of Earth's age come to light

○ When understanding of atoms and radiometric dating of rocks came about

What is a half life

○ Time it takes for half the atoms in a given sample to decay

What is the significance of there not being short-lived isotopes in Earth's rocks

○ It means that Earth is very old, far older than most predicted

What is radiometric dating

○ Estimating the age of something based on isotope ratios

What is an isochron

○ Based on radiometric dating
○ Shows when something formed
○ All the rocks formed at the same time

How old is Earth

○ About 4.568 billion years

How old is the solar system

○ About 4.6 billion years

Why can't you use radiometric dating in fossils

○ They usually don't contain the isotopes

What do you do instead

○ Radiometric dating of the nearby rocks

What is radio carbon dating

○ Using the decay of C-14 to date organic material less than 50,000 years old
○ Half-life of 5730 years

Why is the fossil record incomplete

○ Organisms are eaten or destroyed before the slow process of fossilization can take place,
erosion from exposure to the elements
○ Even if it does fossilize, can be destroyed before observed

What else can fossils show

○ Mating behaviors
○ Nesting behaviors
○ Entire ecosystems
○ Reproductive strategies
○ Cellular structure (melanosomes)

How old is the galaxy

○ 10 billion years

How old is the universe

○ 14 billion years

What is life

○ An assemblage of molecules that can capture energy from the environment and replicate itself

What happened 4.5 bya

○ Earth cooled and formed a crust
○ Liquid oceans began to appear

What happened 4.4 bya

○ Large collision lead to formation of the moon

When happenedd 3.8 bya

○ Late heavy bombardment ended

What is an indication that all life today was descended from a common ancestor

○ Only L amino acids

What are zircons

○ Microscopic crystals
○ Potentially a biomarker
○ 4.1 bya

Why is early evidence of life controversial

○ Many of the "biomarkers" could potentially have been produced by a non-living source

What is the most widely accepted first evidence of liife

○ Stromatolites
○ 3.5 bya

What are stromatolites

○ Mineralizations of bacteria

What type of life was there for the first 2 billion years

○ Single celled
○ Eukaryotes, Bacteria, and Archaea all came about during this period

What are prokaryotes

○ Single-cellular organisms that lack membrane bound organelles and nucleus
○ Bacteria
○ Achaea

What are eukaryotes

○ Have membrane bound organelles
○ Arose from symbiosis between archaea and bacteria

What happened 2.4-2.7 bya

○ Cyanobacteria came about and started producing oxygen

What happened 2.3 bya

○ Great oxygenation event
○ Oxygen = toxic, kills most bacteria
○ Earth covered in rust

What is aerobic respiration

○ Requires oxygen to make ATP, providing cells with energy
○ More efficient than anaerobic

What happened 2.1 bya (and eukaryotes 1.6bya)

○ Multicellular life

What are the advanteges of multicellular life

○ Damage protection
○ Protection from predation
○ Division of labor between cell types

What happened 715 mya

○ Snowball earth hypothesis (likely from volcanic activity)
○ Lasted 100 million years

What happened after the snowball earth

○ Life got larger and more complex

What happened around 600-800 mya

○ First animals, resembled sponges

What are some features that define animals

○ Multicellular
○ No cell walls
○ Respond to their environment in complex ways
○ Complex nervous system
○ Get energy by eating things

What happened 585 mya

○ First evidence of animal locomotion, burrow