What is evolution? Explain what you know.
EXPLORING CHANGE OVER TIME
HOW DID ORGANISMS EVOLVE?
Evolution is the change in heritable traits through generations CHANGE OVER TIME Occurs in populations, not individual organisms
At the time life emerged on earth (about 3.8 billion years ago), the atmosphere is thought to have contained very little oxygen! First cells were thought to be anaerobic Recall that anaerobic means without oxygen As the atmosphere of the Earth changed, so did the development of organisms
These prokaryotic (simple), anaerobic cells were able to exist in Earth s early atmosphere As Earth s atmosphere and conditions changed, photosynthetic prokaryotes evolved, using sunlight to produce food What molecule do photosynthetic organisms produce as byproduct (waste)?
Eventually, Earth s atmosphere became filled with oxygen Aerobic organisms evolved This resulted in the evolution of eukaryotic complex multicellular organisms we have on Earth today!
The endosymbiotic theory proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms.
~2 billion years ago: Evolution of internal membranes in prokaryotes The result was the ancestor of all eukaryotic cells. Endosymbiotic theory: Eukaryotic cells formed from a symbiotic relationship among several different prokaryotic organisms Prokaryotes that use oxygen to generate energy-rich molecules of ATP evolved into mitochondria. Prokaryotes that carried out photosynthesis evolved into chloroplasts.
Fossils show us the similarities between organisms of the past and present 220 Million Years Ago 190 Million Years Ago Today
Homologies describe similarities between the anatomical structures of species
Vestigial structures are anatomical structures that still appear, but are no longer used! Examples: Tails in humans, legs in snakes Suggests that these structures may have existed at a previous time or in an ancestor; organisms evolved and structures not needed
Insects and animals often have very similar embryonic development Ex. All vertebrates (have a backbone) have similar development Suggests a common ancestor
Comparison of DNA and macromolecules between organisms Through gel electrophoresis Tells us what organisms are closely related
1. Explain how cells are thought to have evolved over time. 2. What are the different piece of evidence we have for evolution?
Bird wing Moth
Type of Evidence?
baby elephant in womb
1-2 feet long
EMU OSTRICH
SURVIVAL OF THE FITTEST
Charles Darwin is best known for his contributions to the theory of Evolution On a five year voyage on a ship called the Beagle, Darwin recorded his observations of organisms and fossils he found along the way This led Darwin to develop the idea of evolution and natural selection
Survival of the Fittest means that those organisms best adapted to their environment will survive, reproduce, and pass on genes Fittest means best adapted, not strongest!
Any heritable trait an organism has that helps it to survive What are some adaptations of this falcon?
If an organism does not have adaptations to best fit its environment, it will die Survival of the Fittest Example: Bird beaks-imagine that birds had different sized beaks in an area where the food source was seeds. In order to crack them, the birds needed a large, strong beak. Which would survive and reproduce?
Species have the potential to increase exponentially, but environmental factors maintain lower population numbers Resources required to sustain life Environmental conditions Relationships among organisms in food web Changing environments select for specific phenotypes Those organisms with favorable adaptations survive, reproduce, and pass on their alleles to future generation Over time, the accumulation of favored alleles leads to a change in species (change over time = evolution)
Organisms are constantly changing and adapting; bacteria reproduce and evolve quickly to adapt to constant changes! Humans often use antibiotics to combat harmful bacteria (ex. Staphylococcus) Some bacteria are born with a natural resistance (an adaptation!) to the antibiotic These bacteria will survive and reproduce, creating a group that are resistant to the drugs
Pesticide Resistance in Plants Antivirals Passive Immunity: Immunity to certain diseases is given from mother to baby at birth Continued through antibodies passed through breastmilk Active Immunity: Immunity acquired through exposure to a disease After exposure, your body builds up an immunity Vaccines allow you to artificially gain an active immunity without exposure to the actual disease
Genetic Recombination Dominant and Recessive alleles in genes, along with polygenetic traits and complex genetics, lead to individual organisms with different phenotypes (and thus, adaptations) Mutations Changes in DNA sequences can introduce both good and bad new traits into a population (ex. Immunities, resistant bacteria, pesticide resistant plants)
What does it mean to be the fittest individual? Which moth has the greatest chance for survival? Why? Over time as natural selection occurs and the moths that survive go on to reproduce, what color will be most common in the population?
HOW SPECIES CHANGE OVER TIME
Speciation refers to the evolutionary process by which new biological species arise
When one extreme phenotype has the best chance to survive As a result, the frequency (number) of those with that phenotype shift over time Woodpecker beaks
DIRECTIONAL selection Using the diagram as evidence, how did the horse evolve over time? Hypothesize why these changes could have happened.
When the intermediate phenotype has the best chance to survive Heterozygote advantage Birth weight
When both extreme phenotypes have the best chance to survive Peppered moth
Decide if the following scenarios are directional, stabilizing, or disruptive selection. In a population of green, white, and brown grasshoppers, the green often survive due to their body color matching the grass. Brown and white are often preyed upon by predators. In mollusks, white and black mollusks survive well at different levels of water. Grey mollusks are a target for predators. In human babies, small and large babies bring complications at birth. As a result, most babies are born in the 6-8 pound range.
HOW SPECIES CHANGE OVER TIME
When mountains, islands, etc. keep a population isolated Species will meet different environmental challenges, change and evolve independently than the original population
Lemurs of Madegascar
Differences in phenotype within one gene Example: Eye color in humans Brown eyes are naturally protected from the sun s glare
When one species evolves due to a specific interaction with another species Example: Flowers and birds/insects; flowers pollinated by hummingbirds often have a narrow, tubular shape
The change in a frequency of a gene variant (allele) in a population due to random chance Due to a random event, a significant change happens to the organisms in a population Much more frequent is small populations! Example: Founder Effect Bottleneck Effect
1. What is survival of the fittest? How does this fit into the idea of natural selection? 2. What would occur over time if you had a group of organisms who were separated by a river? 3. Sometimes, natural selection does not play out how we expect. What is it called when selection takes place due to random chance?
CLASSIFYING ORGANISMS
Classification systems are how we organize organisms This is called taxonomy The classification of organisms has changed and evolved over the years due to new knowledge Greater understanding of evolutionary relationships, thanks to DNA technology, has allowed for more detailed classification
The classification of organisms begins with the largest groupings and moves down to the smallest (domain species) The classification order is as follows: Domain Kingdom Phylum Class Order Family Genus Species Easy way to remember: King Phillip Came Over For Grandma s Spaghetti!!!
Group of the same organisms Live together Mate and produce viable offspring Viable means they can have babies of their own
The scientific name of an organism is the Genus and Species of an organism Always written in italics Example: Humans are Homo Sapians Only species are able to interbreed!
Only species are able to interbreed. Organisms of two different species normally will not breed Sometimes, organisms within the same genus are able to interbreed, but the offspring are not viable (they cannot reproduce!) Example: Mules; Ligers These hybrid organisms are much more common in captivity than in the wild
1. What is the scientific name for humans? 2. What components make up the scientific name? 3. What classifies a species?
A key that helps identify an organism Uses questions to lead you to the scientific name of an organism By looking at features of an organism, the key will help you determine what it is!
1. Organisms are classified into 7 major groups. List these groups in order from largest to smallest. 2. Which is the best description of how natural selection changes a species over time? a) Survival of the strongest organisms in an environment b) Elimination of the smallest organisms by largest organisms c) Survival of the organisms genetically best adapted to the environment d) Survival of the organisms that occupy the largest area in an environment
Shows the evolutionary relationship between organisms Can show which organisms are more closely related than other organisms
Which organism is more closely related to man? Which organism is man more closely related to: Frog or bird? Why?
Shows relationships up-close; characteristics they share
1. Which two organisms are most closely related? 2. What trait do lizards have that salamanders don t?
A. Evolution is survival of the smartest B. Evolution is survival of the strongest C. Evolution is survival of the fittest D. Evolution is survival by luck
The forelimbs of whales, dogs, humans, and bats are all similar in their arrangement and structure. What category of evidence is exemplified? a) Fossils b) anatomical similarities c) biochemical comparison d) embryological comparison
a) Organs b) Adaptations c) Natural Selection d) Vestigial Structures
a) It doesn t exist b) It can reproduce and have offspring c) It s parents are not the same d) It cannot reproduce and have babies of its own
a) Variation b) Natural Selection c) Isolation d) Speciation
How does pesticide resistance in insects lead to the evolution of the overall insect species? a) The species will develop different eating methods to avoid the pesticides b) Insects surviving pesticide applications become weaker and will eventually die c) Farmers will use different pesticides to kill the insects, eliminating the species d) Pesticide-resistant insects will survive and reproduce, increasing the percentage of pesticideresistant insects in the population
Which immune response is passed from mother to child through breast feeding? a) Active b) Passive c) Humoral d) Cell-mediated
Natural selection cannot occur without a) competition for unlimited resources. b) gradual warming of Earth. c) genetic variation in species. d) asexual reproduction in species.
The classification of some organisms has changed. Which new process is used to reclassify organisms? a) Organisms are now given Latin-based scientific names b) Structures are now examined at the molecular level c) Organisms are now divided into three kingdoms d) Structures are now used to classify organisms
Define the following terms: Fitness Natural Selection Speciation Genetic Drift Species
Go to: quizlet.live Enter code on board and enter your first name. You must enter your first name. You will be placed in random teams-you should move to be near your team. Careful-a wrong answer will send you back to start! First team to finish all?s wins! To review on your own later, go to: https://quizlet.com/_2bktyo Password: Bio2016
You have a test today! Take 10 minutes to study: Evidence of Evolution Darwin s Theory of Evolution Types of Selection Speciation Dichotomous Keys Phylogenetic Trees Classification: REMEMBER-King Phillip Came Over For Grandma s Spaghetti!