EVOLUTION: the process of change in allelle

frequency over time

Evolution is the idea that new species develop from earlier species by accumulated changes. This is also referred to as “descent with modification”.

Jean Baptiste Lamarck*Use and Disuse Hypothesis (1809)

No longer accepted- Behavior does NOT affect inheritance.

*Inheritance of Acquired Traits

Lamarck’s Theories

• Tendency Toward Perfection – acquiring features that help them live more successfully in their environment – Ex: birds and flying

• Use and Disuse – Alter size and shape of their bodies– Ex: birds transform front limbs to wings

• Inheritance of Acquired Traits – pass on traits to offspring– Ex: weight lifter

Charles Darwin

1831 Traveled to the Galapagos Islands where there was a variety of climates

among the islands

He observed much diversity in living things and how well

suited they were to their environments.

Darwin observed variety within species and also studied artificial selection

Led him to the theory of evolution by natural selection

What is natural selection?

Struggle for existence leads to survival of the fittest (Natural Selection)

The “fittest” are those with an inherited characteristic that makes it better suited to survive and reproduce.

These characteristics are called Adaptations.

Adaptations!Inherited characteristic that increase

an organism’s chance of survival• Why are most animals in the artic white?

– So they blend in with the snow and avoid being seen!

• Why do sharks have such sharp teeth?

– It allows them to catch their prey!

• Why do elephants have such big ears?– To let heat escape their bodies so they can – stay cool!

Natural Selection results in changes in inherited characteristics of a population due to the

environment, increasing the species’ fitness in that environment.

These changes are observed over long periods of timeand many generations.

Hutton and Lyell

• Studied geology and geological change• Discovered that the Earth is millions of

years old• The process that changed Earth in the

past are the same processes that operate in the present– Weathering of rock– Uplifting to form mountain ranges

Lyell’s Influence on Darwin

• If the Earth can change over time, might life change as well?

• Realized it would take many, many years for life to change in the way he suggested– This would only be possible if the Earth were

extremely old!

Population Growth

• Malthus reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone.

• Darwin asked a couple of questions:– What causes death of so many individuals?– What factors determine which ones survive

and reproduce and which ones do not?

5 parts of Darwin’s Theory of Natural Selection

• Genetic Variation – Ultimate source = MUTATIONS!

• Overproduction of Offspring

• Struggle for Existence

• Survival of the Fittest

• Descent with Modification

Organisms produce more offspring than can

survive.

• Example: A frog can lay 200 eggs, yet not all eggs will survive to become adult frogs.

Struggle for Existence

• Members of each species compete regularly to obtain food, living space, ect.

• Prey – faster, better camouflaged, or better protected

Survival of the Fittest

• How well an organism is suited to its environment

• **Fitness – ability to change (adapt) in order to be able to survive and reproduce

• Is this always the strongest or the biggest organism????

Descent with Modification – Common ancestor and change over time in a population

All living things are related due to common ancestors- Principle of “Common Descent”

Results of Evolution -- Speciation!!

• Speciation is the process that creates new species!

• A species is a group of organisms that can naturally interbreed and produce fertile offspring.

• The Liger--the offspring of a tiger and a lion. • Tigers and lions are still considered separate species,

because although they can produce

offspring, the offspring

is not fertile.

Evidence of EvolutionA. Fossils – Mineralized remains or imprints of organisms

from the past

“Missing Links” – Intermediate fossils between groups of organisms

Fossil record is not complete!

B. Geographic distribution of living species

Species evolve differently in different environments

Different species evolve similarly in the same type of environment

C. Amino Acid Sequences (DNA Evidence)– More closely related, more aa sequence similarities

should be seen

D. Anatomy–

Similar body structures that don’t necessarily have similar functions(Homologous Structures)

Similar structures with reduced size and lesser function or no function (Vestigial Structures)

Evidence of Evolution --Anatomical/Physiological Similarities• Notice how there are similar bones and

similar structures in humans, birds and whales!

– Can you tell which is the bird and which is the whale?

Analogous Structures

• Serve the same function but are anatomically different. Serve as evidence that the organisms evolved independently

Vestigial Organsorgan that serves no useful functionover generations, they reduce in size

Evidence of Evolution -- Embryology!

• It is believed that all vertebrates evolved from a common ancestor. The genetic information that guides their development is nearly the same.

• That's why scientists can learn about human development by studying other organisms--including zebrafish.

E. Embryonic Development –

Similarities in development of embryos of organisms

Extinction!

• Extinction occurs when there are no members of a species left alive.

5 parts of Darwin’s Theory of Natural Selection

• Genetic Variation – Ultimate source = MUTATIONS!

• Overproduction of Offspring

• Struggle for Existence

• Survival of the Fittest

• Descent with Modification

Relative Dating

Can determine

Is performed by

Drawbacks

Absolute Dating

Comparing Relative and Absolute Dating of Fossils

Imprecision and limitations of age data

Difficulty of radioassay laboratory methods

Comparing depth of a fossil’s source stratum to the position of a reference fossil or rock

Determining the relative amounts of a radioactive isotope and nonradioactive isotope in a specimen

Age of fossil with respect to another rock or fossil (that is, older or younger)

Age of a fossil in years

Relative vs. Absolute Dating

Principle of Superposition• In an undisturbed sequence of

sedimentary rocks, the oldest rocks are on the bottom with the most recent on top.

How fossils are formed

Water carries small rock particles to lakes and seas.

Dead organisms are buried by layers of sediment, which forms new rock.

The preserved remains may later be discovered and studied.

Glaciations; mammals increased; humans

Mammals diversified; grasses

Aquatic reptiles diversified; flowering plants; mass extinction

Dinosaurs diversified; birds

Dinosaurs; small mammals; cone-bearing plants

Reptiles diversified; seed plants; mass extinction

Reptiles; winged insects diversified; coal swamps

Fishes diversified; land vertebrates (primitive amphibians)

Land plants; land animals (arthropods)

Aquatic arthropods; mollusks; vertebrates (jawless fishes)

Marine invertebrates diversified; most animal phyla evolvedAnaerobic, then photosynthetic prokaryotes; eukaryotes, then multicellular life

Cenozoic

Mesozoic

Paleozoic

PrecambrianTime

Quaternary

Tertiary

Cretaceous

Jurassic

Triassic

Permian

Carboniferous

Devonian

Silurian

Ordovician

Cambrian

1.8–present

65–1.8

145–65

208–145

245–208

290–245

363–290

410–363

440–410

505–440

544–505

650–544

Key EventsEra Period Time(millions of years ago)

Summary of major events (pg. 429-34)

Hypothesis of early Earth

• Very hot surface from colliding meteorites

• Very hot planet core from radioactive materials

• Volcanoes spewing lava and gases that helped to form the early atmosphere

Hypothesis of early Earth

• About 4.4 billion years ago, Earth might have cooled enough for the water in its atmosphere to condense.

• This might have led to millions of years of rainstorms with lightning, enough rain to fill depressions that became Earth’s oceans.

• The oldest rocks dated are 3.9 million years old.

Fossils: evidence of an organism that lived long ago that is preserved in

Earth’s rocks• Paleontologists

estimate that about 95% species are extinct from life’s origins.

• Climate and ancient geography can be determined from fossils.

Types of FossilsFossils Types Formation

Trace fossils

Casts

Molds

Petrified/Permineralized

fossils

Amber-Preserved orfrozen fossils

A trace fossil is any indirect evidenceA trace fossil is any indirect evidenceleft by an animal and may include afootprint, a trail, or a burrow.

When minerals in rocks fill a space left by a decayed organism, they makea replica, or cast, of the organism.

A mold forms when an organism isA mold forms when an organism isburied in sediment and then decays,leaving an empty space.

Petrified-minerals sometimes penetrateand replace the hard parts of an organism. Permineralized-void spacesin original organism infilled byminerals.At times, an entire organism was quickly trapped in ice or tree sap thathardened into amber.

What has been learned from fossils

• several episodes of mass extinction that fall between time divisions– mass extinction: an event that occurs when

many organisms disappear from the fossil record almost at once

• The geologic time scale begins with the formation of Earth about 4.6 billion years ago.

Continental drift

• Earth’s continents have moved during Earth’s history and are still moving today at a rate of about six centimeters per year.

• The theory for how the continents move is called plate tectonics.

Miller-Urey experiment showed one possible way for inorganic molecules to form organic molecules. Mixture of gases

simulating atmospheres of early Earth

Spark simulating lightning storms

Condensation chamber

Cold water cools chamber, causing droplets to form

Water vapor

Liquid containing amino acids and other organic compounds

Endosymbiotic theory

Eukaryotic cells may have engulfed prokaryotic cells & by mutualism created the “first mitochondria.” Autotrophic bacteria are Cyanobacteria with chlorophyll

• So, Eukaryotic cells may have engulfed prokaryotic cyanobacteria & by mutualism created the “first chloroplast.”

Macroevolution Large-scale evolutionary patterns and

processes that occur over long periods of time. Includes 6 topics:ExtinctionAdaptive radiationConvergent evolutionDivergent evolutionPunctuated equilibriumChanges in developmental genes

Patterns of evolution

• Darwin believed that organisms evolved gradually.

• Niles Eldredge and Stephen Jay Gould believed punctuated equilibrium is how organisms evolved, periods of rapid evolution followed by periods of stasis.

Adaptive Radiation

• Single species or small groups of species evolved into diverse forms living in different ways.

Convergent Evolution

• Adaptive radiation can produce unrelated organisms that look similar due to similar environments.

Coevolution • Example: “This butterfly acquires a cardiac glycoside from members of the genus Asclepias. Because of their milky sap, these are commonly referred to as milkweed plants. The plants produce this toxin as a defense against herbivory, but the Monarch has the ability to sequester the toxin in fatty tissues so that it makes the butterfly unpalatable while not poisoning the butterfly.”

http://ecology.botany.ufl.edu/ ecologyf02

The process by which two species evolve in response to changes in each, other over time.

Levels of Organization 1. species-a group of organisms so similar to each other that they can breed and produce fertile offspring 2. populations-groups of individuals of the same species that live in in a given area 3. communities-all the different populations that live in a defined area 4. ecosystem-all the communities in a given area together with the physical environment 5. biome-a group of ecosystems that have the same climate and similar dominant communities

II. Energy Flow A. Producers or Autotrophs-use energy from the

environment to assemble simple inorganic compounds into complex organic molecules

**make their own food!1. photosynthesis-process through which plants and algae take light energy to power chemical reactions that convert CO2 and H2O into O2 and energy-rich carbohydrates 2. chemosynthesis-process through which some bacteria break down inorganic molecules releasing energy that they use to make energy- rich carbohydrates

Capture energy from sunlight or chemicals and use that energy to produce food.

Use energy from the environment to fuel the assembly of inorganic compounds into organic molecules

PRODUCERS/AUTOTROPHS

(Includes plants, some algae, & some bacteria)

B. Consumers or Heterotrophs-cannot harness

energy from the environment; must get their energy from other organisms

1. herbivores - eat only plants2. carnivores - eat only animals3. omnivores - eat both plants and animals4. detritivores – eat dead matter and recycle

them to the soil 5. decomposers – break down organic matter

D. Ecological Pyramids- a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or web 1. Energy pyramid-

Only about 10% of the energy available within one trophic level is transferred to organisms at the next trophic level

**Rest is given off as heat!!!**

2. Biomass pyramidbiomass-the total amount of living tissue within a given trophic level

3. Pyramid of numbers- shows relative number of individual organisms at each tropic level

Only about 10% of available energytransfers to the next level

If we startwith 4000caloriesof foodenergy atthe base,how muchis availablefor the man?

How much would he lose as heat and use for body processes?

ENERGY PYRAMID

Pyramid of Numbers

When would a pyramid of numbersnot appear as a pyramid?

BIOMASS PYRAMID

Cycles of Matter

• Unlike energy flowing in one direction, matter cycles!

• Biogeochemical cycles• Systems do not use up matter, they transform it• The same molecules are passed around again

and again in the biosphere.• Nutrients: all chemical substances that an

organism needs to sustain life.• Passed between organisms and environment

The Water Cycle

Carbon Cycle• Four main process move carbon through

its cycle:1. Biological process- photosynthesis, respiration and decomposition2. Geochemical process- erosion and volcanic activity3. Mixed biogeochemical- burial and decomposition of dead organisms converted into fossil fuels4. Human activities- mining, cutting and burning forests and burning fossil fuels

Nitrogen Cycle• Organisms require nitrogen for AA.• Most abundant: nitrogen gas or N2 - 78% of atmosphere• Ammonia, nitrate and nitrite ions are found in waste products

– Also found in ocean and large water bodies• Human activity adds nitrogen as nitrate due to fertilizers

• Nitrogen fixation – bacteria covert nitrogen gas into ammonia Nitrates/nitrites producers use these to make proteins!!

• Denitrification – When organisms die, decomposers return nitrogen to the soil as ammonia – taken in by producers. Soil bacteria convert nitrates nitrogen gas, releasing nitrogen back into the atmosphere!!!

Phosphorus Cycle

• Essential because part of DNA and RNA• Not very common in the atmosphere• Remains mostly on land in rock and soil

minerals, and in ocean sediments as inorganic phosphate.

• When rocks and sediments wear down, phosphate is released.

• On land, some of the phosphate washes into rivers and streams where it dissolves.

Nutrient Limitation

• Primary Productivity: rate at which organic matter is created by producers

• Factors: amount of nutrients available• Limiting Nutrient: single nutrient that limits

ecosystem because is scarce or slowly cycles– Nitrogen in oceanic environments– Phosphorus in freshwater environments

• Ex. Farmers use fertilizers– Algal bloom

Types of Symbiosis

• Mutualism• both species benefit• Commensalism•   one species benefits, the other is unaffected• Parasitism•   one species benefits, the other is harmed

(must have a host)• Predation• One species benefits, the other is harmed.

CompetitionCompetition

• Occurs when organisms of the same or Occurs when organisms of the same or different species attempt to use an different species attempt to use an ecological resource in the same place at ecological resource in the same place at the same time.the same time.

• Resources-any necessity of lifeResources-any necessity of life

Competitive Exclusion PrincipleCompetitive Exclusion Principle

• No two species can occupy the same No two species can occupy the same niche in the same habitat at the same niche in the same habitat at the same time.time.

A. biotic factors- the biological influences on organisms within an ecosystem

-living things!

B. abiotic factors-physical or nonliving factors that shape an ecosystem

-nonliving things!

C. niche-the full range of physical and biological conditions in which and organism lives and how it uses them

NICHE describes the job of the organismwithin the ecosystem – it is the full range of

physical and biological conditions itlives in and out it uses those conditions!

Here is a picture of a wormand its niche…how can we describe a worm’s niche?

Describe your niche!!

The Role of ClimateThe Role of Climate

• Are all species able to tolerant all Are all species able to tolerant all environmental conditions?environmental conditions?

• Temperature, precipitation and other Temperature, precipitation and other environmental factors in the atmosphere environmental factors in the atmosphere combine to produce climate and weather.combine to produce climate and weather.

• WeatherWeather-day to day -day to day

• ClimateClimate-year to year-year to year– Climate is caused by many factors.Climate is caused by many factors.

The Greenhouse EffectThe Greenhouse Effect

• Atmospheric gases Atmospheric gases trap heat energy trap heat energy and maintain Earth’s and maintain Earth’s temperature range.temperature range.

• Gases act like a Gases act like a “glass window” of a “glass window” of a greenhouse.greenhouse.

• Heat is retained by Heat is retained by layer of greenhouse layer of greenhouse gases creating gases creating effect.effect.

Greenhouse EffectGreenhouse Effect

• Greenhouse gases allow solar energy to Greenhouse gases allow solar energy to penetrate the atmosphere.penetrate the atmosphere.

• Converted into heat energy as it hits the Converted into heat energy as it hits the Earth’s surface and radiates back into the Earth’s surface and radiates back into the atmosphere.atmosphere.

• But, the gases do not allow the escape But, the gases do not allow the escape as easily as the entrance.as easily as the entrance.

• In turn, heat is trapped in the In turn, heat is trapped in the atmosphere.atmosphere.

Latitude’s Effect on ClimateLatitude’s Effect on Climate

• Earth is tilted, so solar Earth is tilted, so solar radiation strikes at radiation strikes at different parts of different parts of Earth’s surface at Earth’s surface at angles that vary at angles that vary at different times of year.different times of year.

• This causes three This causes three climate zones: polar, climate zones: polar, temperate and tropical temperate and tropical

Winds and Ocean CurrentsWinds and Ocean Currents

• The unequal heating of Earth’s surface The unequal heating of Earth’s surface drives wind and ocean currents drives wind and ocean currents transporting heat throughout the transporting heat throughout the biosphere.biosphere.

• The upward movement of warm air and The upward movement of warm air and downward movement of cool air create air downward movement of cool air create air currents or winds moving heat.currents or winds moving heat.

• The flow of water due to temperature as The flow of water due to temperature as well as by winds causes ocean currents. well as by winds causes ocean currents.

• Ocean currents also transport heat energy Ocean currents also transport heat energy and in turn affect weather and climate.and in turn affect weather and climate.

Ecological SuccessionEcological Succession• Ecosystems constantly change due to Ecosystems constantly change due to

natural and human disturbances.natural and human disturbances.• Series of unpredictable changesSeries of unpredictable changes• Primary succession: succession that Primary succession: succession that

occurs on surfaces with occurs on surfaces with no soilno soil– Ex. After a volcanic eruptionEx. After a volcanic eruption

• Pioneer speciesPioneer species• Secondary succession: Secondary succession: soil is presentsoil is present

– Ex. Land cleared for farming is abandoned Ex. Land cleared for farming is abandoned or after wildfires in woodlandsor after wildfires in woodlands

Aquatic EcosystemsAquatic Ecosystems

• Determined primarily by depth, flow, Determined primarily by depth, flow, temperature, and chemistry of the temperature, and chemistry of the overlying water.overlying water.

• Marine – saltwater/oceanicMarine – saltwater/oceanic– Limiting Nutrient = nitrogen! Limiting Nutrient = nitrogen!

• Freshwater – flowing (rivers) or standing Freshwater – flowing (rivers) or standing (lakes, ponds)(lakes, ponds)– Limiting Nutrient = phosphorus! Limiting Nutrient = phosphorus!

BiomesBiomes

• Complex terrestrial communities that Complex terrestrial communities that covers a large areacovers a large area

• Tolerance: ability to survive and reproduce Tolerance: ability to survive and reproduce under conditions that differ from optimal under conditions that differ from optimal onesones

• MicroclimateMicroclimate

The History of Organization

Aristotle 384-322 BCInterested in biological classification.

Patterns in nature.

Carl Linnaeus1707-1778 ACE

Father ofBiological

Classification!

Binomial Nomenclature

Two-word naming system– Genus

• Noun, Capitalized, Underlined or Italicized

– Species• Descriptive, Lower Case,

Underlined or Italicized

• Ex: Homo sapien

What is Classification?

Scientist who classify ororganize organisms (animals and plants) are called taxonomists.

Taxonomists study taxonomy.Classification arranges

objects, ideas, or information

into groups by finding

common traits or characteristics.

Cladograms are used to…

• Organize organisms based on evolutionary relationships.

In other words…• who is related to who

and where did we come from…

• Groups are also arranged in

• hierarchical order.

Hierarchical Classification• Taxonomic categories

– Kingdom (big) King– Phylum Philip– Class Came– Order Over– Family For– Genus Grape– Species (small) Soda

Using a dichotomous keyAt each step of the process of using the key, the user is

given two choices; each alternative leads to another question until the item is identified.

1a. If the leaves are flat….go to question 4. 1b. If the leaves are needle-like….go to question 2.2a. Are the needles in a bunch? Go to question 52b. Are they spread along the branch?“…pine tree

Eventually, when enough questions have been answered, the identity of the tree is revealed.

•Gene mutations result from changes in a single gene. Chromosomal mutations involve changes whole chromosomes.

• Point Mutation – Affect one nucleotide thus occurring at a single point on the gene. Usually one nucleotide is substituted for another nucleotide.

• Frameshift Mutation – Inserting an extra nucleotide or deleting a nucleotide causes the entire code to “shift”.

• Deletion – Part of a chromosome is deleted• Duplication – part of a chromosome is

duplicated• Inversion – chromosome twists and inverts

the code.• Translocation – Genetic information is

traded between nonhomologous chromosomes.