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BIO FINAL EXAM NOTES
Chapter 13: Natural Selection and Adaptation
Population - is a group of organisms of the same species living together in the same geographic area and are breed-able with each other
An entire Population can change(evolve) when some traits are favored over others
Fitness - A relative ability of an organism to reproduce in a particular environment.
Fitness in Bacteria - Low fitness and high fitness tend to determine the effectiveness of antibiotics on bacteria. Low fitness bacteria being highly sensitive to antibiotics
MRSA “Methicillin-Resistant Staphylococcus Aureus”
Infectious Bacterium
Difficult to treat with antibiotics
Killed 10,000 people in the United States in 2012
Staphylococcus aureus (also known as S. aureus or “staph”
Some strains are harmless whereas others cause disease
Drug-resistant strains exist
Approx. 33% of the US has S. aureus
Approx 2% of the US population has MRSA strains of S. aureus
Most of these individuals are disease free
MRSA “Methicillin-Resistant Staphylococcus Aureus” pt 2.
MRSA transfers from person to person by direct or indirect contact
Athletes have increased risk of skin infections because of contact with skin, items, or surfaces that harbor MRSA
MRSA has developed resistance to most antibiotic drugs
MRSA adversely affects people with weakened immune systems
Ricky Lanneti was killed by a MRSA Staph
Antibiotics
Antibiotics interfere with the function of essential bacterial cell structures
Beta-lactams work by interfering with the bacterium’s ability to synthesize cell walls
Bacterial Reproduction and Mutation
Binary Fission - Binary fission is how cells asexually reproduces with one parental cell dividing into two daughter cells
Binary fission occurs quickly but each time it causes some changes to DNA
Antibiotic Resistance, and how its created and spread
Random mutations can create new alleles that cause some bacteria to be resistant to antibiotics
Gene transfer can spread the alleles for antibiotic resistance to other bacteria
Evolution can eventually result in a new species - Natural selection is the mechanism for this
Adaptations are often compromises - Not about “perfecting” organisms
Chance, natural selection, and the environment interact
The variety in any generation may be insufficient for survival, particularly during periods of relatively fast environmental change
Evolution occurs within populations
Key terms:
Gene pool
Microevolution
“Why can’t an individual evolve?”
Fitness - an organism's ability to survive and reproduce in its environment. i.e Having higher reproduction and a longer life = better fitness
Evolution - “The Hardy Weinberg principle”
For a population to evolve, something must act on the gene pool to change how often a particular allele is present in the population. An outside force must act to break the equilibrium of the allele/genotype frequency.
If these 5 Conditions are True for a population, then evolution will not occur:
No Natural Selection
No Mutation
No Migration
Large Population
Random Mating
The Three Main Causes of Evolutionary change:
Natural Selection
Genetic Drift
Gene Flow
If individuals differ in their survival and reproductive success, natural selection will alter allele frequencies. And will eventually make the differing resistant allele the dominating population
Natural selection can alter variation in a population in three ways:
Stabilizing selection - Phenotype of population settles near middle of range
Intermediate phenotypes are better suited to the environment than individuals at either extremes
Ex. Mid range weight babies are more common than heavy or light babies for survival and delivery purposes
Directional Selection - Predominant phenotype shifts in a particular direction
Directional selection occurs when a phenotype at one extreme is favored by the environment
Ex. Dark mice are dominant near dark lava rock because light are easily spotted by predators
Disruptive/Diversifying Selection - Phenotype of population is at both extremes of range
Extreme phenotypes are better suited to the environment than individuals with intermediate phenotypes
Ex. Finch beaks allow finches to feed off large hard, and soft small seeds. Medium beaks aren’t good for cracking either seed
Natural Selection in Bacteria
Antibiotics change the environment in which bacteria live.
When antibiotics are present, bacteria with genes for resistance have the greatest fitness
This creates strong directional selection for antibiotic resistance
What is Natural Selection?
The process where organisms that are better adapted to their environment survive and have the most offspring.
Start with a random mutation
Then a condition of the environment or a resource goes to work
temperature, water availability, dominant color, light availability, etc.
This RESULTS in evolution - it is a mechanism!
Natural Selection in Humans
Missing wisdom teeth
Random mutation in humans
Lactose intolerance
Inability to digest lactose (sugar) in milk because of low lactase production
Lactase production decreases over time
Ancestors did not drink milk
High-altitude breathing
Indigenous Tibetans in the Himalayan mountains
High altitude areas have lower available oxygen
The blood of tibetans produces more oxygin transporting hemoglobin proteins
A single mutation from ~3,000 years ago
Bergmann’s Rule and Allen’s Rule
Allen’s Rule: body shape is linear (longer and skinnier) in warm climates and rounder
Bergmann’s Rule: body size is larger in cold areas and small in warm areas
Plant Natural Selection
Carnivorous plants
Cactus
Toxins
Artificial Selection
Selection that is manipulated by humans. Examples include Dogs, and Corn.
Risks of artificial selection
As we get traits we do want, we get many traits we don’t
In animals:
Increased genetic problems
Changes in behavior
Reduced fertility
Increased obesity
In plants:
Increased disease susceptibility
Less ability to adapt
Chapter 13: Evolution of Populations
How would you define “species”?
A species:
Mating
Shares features
Results from speciation
The origin of species is the source of diversity
When speciation occurs, one species splits into two
They share many characteristics
They are descended from a common ancestor
LUCA - Last common ancestor of all cellular life ~3.8 billion years ago
Microevolution is evolution’s smallest scale
changes in the gene pool from one generation to the next
How does microevolution differ from speciation
Microevolution occurs on a smaller scale, speciation results in a whole new species. Microevolution can be a bugs adaptation to pesticides. Speciation can be the Glapagos finch example creating new species of birds
Different species cannot interbreed unlike different microevolution effected organisms
Now back to defining “Species”
A barrier between the reproduction of two species can be an indicator of it being different species. Looks can be deceiving, similar looking species can still be different species. Ex. Eastern and Western meadowlark look exactly the same but have different mating songs and behaviors, leading them to not be able to mate.
The Biological Species Concept
Reproductive isolation vs gene flow
Production of fertile offspring
Reproductive barrier
Some questions to ask:
Are species fixed and stable at all times?
Can we apply this concept of species to asexual organisms?
How about organisms that we describe only through fossils? For example, Cro-Magnon and Neanderthal?
Other definitions of species can be useful, depending on the situation and question asked and here are the following Concepts:
The morphological species concept is based on observable physical traits and can be applied to asexual organisms and fossils Ex. Neanderthal/Cro-Magnon
The ecological species concept defines a species by its ecological niche and focuses on unique adaptations to biological community. Ex. Polar/Grizzly Bears
The phylogenetic species concept defines a species as the smallest group of individuals that share a common ancestor and this form one branch of the tree of life Ex. Tree graph and closely related organisms
Biological species is useful because it focuses on how discrete groups of organisms (species)
Arise
Maintained by reproductive isolation
How do reproductive barriers keep species separate?
Prezygotic Barriers (issues that prevent the ability to produce fertile offspring before fertilization)
Habitat isolation - Location issues
Temporal Isolation - Differing breeding schedules
Behavioral Isolation
Mechanical Isolation
Gametic Isolation
Postzygotic Barriers (issues that prevent the ability to produce fertile offspring after fertilization)
Reduced hybrid viability - Genetic incapabilities not allowing offspring hybrids to survive
Reduced hybrid fertility - No future generations
Hybrid breakdown
Reproductive Isolation:
Ecological isolation
Temporal isolation
Behavioral isolation
Mechanical isolation
Gametic isolation
Hybrid inviability
Hybrid infertility
Checkpoint question Two closely related fish live in the same lake, but one feeds along the shoreline and the other is a bottom feeder in deep water. This is an example of _____ isolation, which is a _____ reproductive barrier.
Answer: 1. Habitat 2. Prezygotic
Three Main Causes of Evolutionary Change are:
Natural Selection
Genetic Drift
Gene Flow
Genetic Drift
Genetic Drift is a change in the gene pool of a population due to chance
In a small population, chance events may lead to the loss of genetic diversity
Ex. The bottleneck effect, the founder effect
Genetic Drift - Random changes in the allele frequencies of a population between generations
The smaller the population, the greater the effect of genetic drift
Founder Effect: A type of genetic drift in which a small number of individuals leaves one population and establishes a new one
Bottleneck Effect: A type of genetic drift that occurs when a population is suddenly reduced to a small number of individuals Ex. A rapid habitat loss and loss of large pecentage of populations
Three Main Causes of Evolutionary Change are:
Natural Selection
Genetic Drift
Gene Flow
Gene Flow - Is the successful transfer of alleles from one population to another
Gene Flow
Movement of alleles from one population to another
Urbanization can prevent gene flow and lead to interbreeding
What causes changes in allele frequency?
Natural selection
Population is better adapted
Nonadaptive evolution
Random changes that do not affect fitness for an environment
Caused by mutation, genetic drive, and gene flow
Nonadaptive Evolution
Nonadaptive evolution can happen through genetic drift.
Change in allele frequencies between generations that occurs purely by chance
Subset of population reproduces
Subset of alleles represented in next generation
Mutation, Gene Flow, Genetic Drift are all Nonadaptive
Natural Selection is NOT Nonadaptive
Why is Genetic Diversity important?
Because of Inbreeding Depression
What is Inbreeding Depression?
Closely related individuals are more likely to share the same alleles
Negative reproductive consequences for a population
Associated with high frequency of homozygous individuals possessing harmful recessive alleles
Hardy-Weinberg Equilibrium
In a nonevolving population, allele and genotype frequencies do not change over time
This is used to identify genes that have changed because of evolutionary mechanisms
Baseline to judge if a population is evolving
Hardy-Weinberg Equilibrium
p²+2pq+q²=1
p² is the frequency of homozygous dominants
2pq is the frequency of heterozygotes
q² is the frequency of homozygous recessives
Hardy-Weinberg Equilibrium
5 necessary conditions:
No mutation creating new alleles
No natural selection favoring some alleles over others
An infinitely large population size (and, therefore, no genetic drift)
No influx of alleles from neighbouring populations (i.e, no gene flow)
Random mating of individuals
p+q=1
say q²= 9% or 0.09
q =0.3
p+q= always equals 1 so..
p=0.7
What is a Gene Pool?
A gene pool is the collection of alleles in a population
Genetic diversity of a gene pool is critical for survival of populations
Natural selection is when evolution is adaptive. Mutation, genetic drift, and gene flow are nonadaptive forms of evolution.
Summary of some terms and mechanisms:
Genetic Drift - Random decrease in genetic diversity, especially in small populations
Gene Flow - Movement of alleles between different populations which spreads genetic diversity
In order for a population to evolve, It must NOT coincide with the Hardy-Weinberg principals
How do new species arise? How do we recognize them?
A species is a population of individuals that can interbreed to produce fertile offspring, according to the biological species concept
Speciation can occur when gene pools are isolated from each other so that the populations diverge genetically over time
Chapter 19: Human Evolution
Primate Characteristics include:
Limber joints
Grasping hands and feet with flexible digits
Short snout
Forward pointing eyes that enhance depth perception
A phylogenic tree shows that all primates are divided into three groups:
Lemurs, Lorises, and Bush Babies
Tarsiers
Anthropoids, including monkeys and apes
The fossil record indicates that anthropoids began diverging from other primates about 55 million years ago.
Apes include - Gibbons, Orangutans, Gorillas, Chimpanzees, and Humans
Compared to other primates they have larger brains relative to body size. Their behavior is more flexable
How do Apes and Monkeys differ physically
Apes
No tail, long arms and short legs, broad chest, less hair
Monkeys
Tail for balance and movement, forelimbs the same length as hind limbs, more hair, less intelligent
Becoming Human
Hominins include modern humans and their extinct relatives
Paleoanthropology, the study of human origins and evolution
Paleoanthropologists have found about 20 species of extinct hominins
Some of these species lived at the same time
Hominidae
Of current species, chimpanzees are most closely related to humans
The last common ancestor was approximately 7 million years ago
Homo Sapiens are characterized by:
Ability to walk upright
Big brain
Ardipithecus Ramidus
4.4 million years ago
Small brain
Bones show it could walk upright
Australopithecus
2.6 Million years ago
Could walk upright
Lived on the ground
Tools
Homo erectus
800,000 years ago
Controlled fire
Homo sapiens
between 800,000-200,000 years ago
Big brain
Better communication and problem solving
How do present day Chimps and Humans differ? - Humans are bipedal (walk upright) andH Humans have much larger brains
What is a clue for Bipedalism
Location of the opening in the base of the skill in which the spinal cord exits. Downwards opening = Bipedal, sideways opening = Not bipedal
Larger brains marked the evolution of Homo
Bipedalism precedes larger brain size
Homo neanderthalensis (Neanderthals) had even larger brains than ours and hunted big game with tools made from stone and wood
Remember this order of ancestors becoming Human:
Ardipithecus ramidus - 4.4 mill yrs, small brain, walk on all fours but could walk on two
Australopithecus - 2.6 mill yrs, could walk up right, lived on ground, tools
Homo erectus - 800k yrs, controlled fire
Homo sapiens - 800k-200k yrs ago, big brain, better communication and problem solving
All living humans have ancestors that originated as Homo sapiens in Africa
Oldest known fossils with definitive characteristics of our own species were discovered in Ethiopia and are 160k-195k years old
Humans evolved in Africa:
“Out of Africa” Hypothesis
Humans originated in Africa
A group migrated to other continents
Fossil evidence shows that earliest modern humans lived in Africa
To further study the out of Africa hypothesis, scientists study mitochondrial DNA (mtDNA)
mtDNA is inherited solely from mothers
mtDNA mutates at a regular rate.
A mother with a mutation in her mtDNA will pass it to all of her children
We can track human ancestry and build an evolutionary tree: “Mitochondrial Eve”
Humans are genetically similar:
Homo sapiens: biological species of humans
Highly similar to one another
Why did human populations evolved different skin colors?
Skin tone reflects levels of melanin
Pigment produced by type of skin cell
Melanin levels are genetically determined
More melanin = darker skin
Skin tone correlates with geography
This is based on the relative position to Earth’s poles
Melanin absorbs UV light
Some nutrients are affected by UV light
Melanin levels in the skin can affect nutrient levels in the body
Folate and Vitamin D - Essential and impacted by sunlight exposure
Folate
Destroyed by UV light in skin
Needed for proper development
Low folate = birth defects
Vitamin D
Produced when skin is exposed to UV light
Needed for immune system, bones, and teeth
Low Vit D = premature birth, rickets, and neurological disease
Why did human populations evolve varying skin tones? (cont.)
In an environment with low UV light
People with low levels of melanin in their skin can form more vitamin D than those with high levels of melanin
Folate is not destroyed
In an environment with high UV light
People with high levels of melanin in their skin can prevent more folate from degrading than those with low levels of melanin
UV levels so high they still can form vitamin D
Light skin helps the body produce vitamin D in sun-poor parts of the world
Dark skin helps protect the body’s folate stores in sunny climates
Natural Selection for Skin Color
Different environments select for different traits and there for different alleles that will be passed down
New alleles such as those for skin colors may appear in population due to mutation
Depending on the environemnet, the allele may or may not undergo selection
Positive selection tends to make the trait more common
Negative selection tend to make it less common
Neutral selection does not influence the trait’s success
Human racial divisions are not supported by genetics
Skin color varies gradually - no clear line between skin color groups
Blood type isn’t effected by skin color either
Skin color correlates with geography
ABO blood types and most traits do not correlate to geography
Chapter 20: Population Ecology
Largest to Smallest group
Biosphere
Ecosphere
Community
Population
Organism
Ecology - The study of interactions
Among organisms
Between organisms and their non living environment
Ecology can focus on different levels, including individuals and populations of individuals from one species
Ecology can also focus on…
Community - Interacting populations of different species in a defined habitat
Ecosystem - All the living organisms in an area and the non living parts of the environment with which they interact
Population Ecology
Its easy to count wolves because they are found in packs unlike Moose who are usually in solitary and randomly on the island.
Moose can be tracked by giving researchers designated areas to count and estimate the total.
Distribution Patterns (3/3)
Random distribution
This may allow individuals to maximize their access to resources
Examples: Moose, pine trees with air-blown seeds
Clumped distribution
When resources are unevenly distributed across the landscape
Or when social behavior dictates grouping
Example: Wolves, or schools of fish
Uniform distribution
Results from territorial behavior
Examples: Penguins often spread out evenly
Some plants produce toxins that prevent seedlings from establishing too close to them
Patterns of Population Growth
Can follow different growth patterns:
Exponential Growth - Unrestricted growth of a population that is increasing at a constant growth rate
Logistic Growth - Starts off fast, levels off due to environment factors that limit ability to reproduce
Carrying capacity
Maximum number of individuals an environment can support given its space and resources
Often depends on availability of habitat: the physical environment in which an animal lives
Population Size
May fluctuate depending on the environment’s carrying capacity
Disease and food shortage may make the population shrink
This allows the environment time to recover its food supply
Population grows again
Boom or bust
Population Interaction
Anything that affects the size of one population could also affect the size of other populations in the ecosystem
Isle Royale
The wolf population increases and decreases depending on the availability of moose (their food)
Moose population increases and decreases depending on the predation from wolves and availability of food
Tree growth depends on foraging by moose
How to measure the health of Populations
Scientist use data such as poop, bones, and urine to test the health of populations
Factors Affecting Populations
Isle Royale - Many factors influence the likelihood that wolves will kill moose
Population density
Numbers of organism per given area
Density-dependent factor - A factor that influences population size and growth depending on the number and crowding of individuals in a population. Ex. Predation
Density-independent factor - A factor that influences population size and growth regardless of number of crowding within a population. Ex. Weather
Abiotic factors - non living components of environment
Biotic factors - living components of environment
Other factors affecting population size include:
Disease - canine parvovirus (cpV)
Climate change - less eating in warm weather, warm weather favors ticks
Wolf Population at Risk - Several factors have brought wolf populations down: disease, lack of food, inbreeding— all in a changing climate
Intervention may be necessary too keep the Isle Royale wolves from extinction
Chapter 22 Ecosystem Ecology
American Tallgrass Prairie
Prairies were once North America’s largest continuous ecosystem
Too wet to be a desert, too dry to be a forest
Range from short grass to tall grass (8ft tall)
Tall Grass prairies:
80% of vegetation dominated by 40-60 grasses
20% is made up of 300 species of forbs and flowers
Reliant on disturbance-fire and grazing
¾ of plant biomass is below the ground
Agriculture has reduced it to 4% of historical range - Rarest ecosystem in the world
Bison and the Prairie
There were once approx. 30 million bison in NA
In late 1800s, they hunted them down to only 500
Due to conservation efforts, only 500,000 bison live there now and mostly on ranches
The American Prairie Reserve (APR) is a rewilding effort to restore 3.2 mill acres of land.
Rewilding - Restoring native wildlife to their original habitat
APR consists of existing public land, plus land purchased by private doners
If completed, APR would have the largest bison herd in the world
Praries are great for cattle
Cattle do not wallow or roam wildely so they do not have the same positive influence for other species as bison
APR is controversial for some, especially ranchers who think of it as a challenge to their way of life
Ecosystems
An ecosystem is all the life and all the non living things and processes in an area.
The American prairie is one example of an ecosystem
Role of Species in Ecosystems
Keystone species play an important role in the ecosystem
Bison are considered keystone species because they are important in their prairie ecosystem
Bison grazing promotes growth of plants other than grass
Bison grazing and wallowing promotes habitat for a wide variety of other animal species
Without Bison, grass overgrowth would crowd other plants
Without Bison, many other animal species lose habitat and become less common
Some species are ecosystem engineers — Keystone species that alter habitat for other species
Nutrient Cycles
Nitrogen is a critical component of proteins, DNA and RNA.
Nitrogen atoms cycle between different chemical compounds as they move from organisms into the soil, water, and air and back to organisms
Phosphorus is critical for the structure. of nucleic acids and phospholipids
In animals, phosphorus is critical for bone and teeth
Phosphorus is added to an ecosystem by the weathering of rocks or through human activities
Temperate grasslands - mostly treeless, cold winters
Biomes - Large areas defined by characteristic plant life
Aquatic
Salinity (saltiness of water)
Life driven by temp
Depth
Movement
Terrestrial
Temperature, precipitation
Plant life is driven by patterns of temp,
Rainfall,
and Seasons
Kinds of Biomes
Tundra occurs in Artic and mountain regions:
Low-growing vegetation
Layer of permafrost soil (frozen all year long) very close to the surface of the soil
Taiga evergreen trees
Long and cold winters, only short summers
Temperate Deciduous Forest moderate winters and rainall
Trees (evergreen or deciduous) drop their leaves in the winter
Temperate Grassland perennial grasses and other nonwoody plants
In North America, prairies are an example of grasslands
Mediterranean long, hot, dry summers and cool, damp winters
Short evergreen trees and shrubs with leathery leaves are found here
Tropical forest warm temperatures and suddicient rainfall to support trees
Deciduous or evergreen
Savanna warm temperatures and two seasons (dry and rainy)
Primary vegetation is grasses with some shrubs and rare trees
Desert extreme dryness
Cold deserts - cold winters and hot summers
Hot desert - uniformly warm all year
Marine Biomes
Aquatic: Marine
This biome covers ¾ of the globe and includes oceans, coral reefs, and estuaries (where rivers meet sea)
Aquatic: Freshwater
Low salt
Includes ponds, lakes, rivers and streams, and wetlands
Water Cycle
Freshwater on land flows to the ocean or seeps into underground aquifers
Water re-enters the atmosphere via evaporation and falls back down via precipitation
Water from the vas Ogallala Aquifer supplies many crops in the midwest
If aquifers like this are not replenished, they will run out
Areas such as ARP can help aquifers recharge because they do not require the use of water
To remember the order of taxa in biology (Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species, [Variety]): "Dear King Philip Came Over For Good Soup
Exam 1 Content:
Domains of Cellular Life Slides:
3 Domains of Cellular Life - Archaea, Bacteria, Eukarya
Cell Theory:
Cells come from other cells (cell division)
Cells are the basic unit of structure and organization in organisms
All living things are made of cells
Key features in Cells:
Cell Membrane - Allows the interior to be different from exterior. Made with lipids and proteins
Genetic Material - Chromosomes carrying genes made of DNA
Ribosomes - Make the proteins encoded by DNA as directed by RNA
Cytoplasm - Semifluid of proteins, enzymes, sugar, salt
Bacteria vs Eukaryotes
Bacteria cells ONLY
DNA floating freely in cytoplasm
No organelles
Cell wall made of peptidoglycan, a rigid structure enclosing the cell membrane\
Eukaryotic cells ONLY
A nucleus: an organelle that contains the DNA
Many organelles
Organelles:
Nucleus: - House the cell’s DNA
Endoplasmic Reticulum (ER): Makes protein and lipids
Golgi apparatus: Packages and transports protein
Mitochondria: Extracts energy and make it useful
Lysosomes: Digest cell parts and food molecules
Chloroplast: plants and algae - for photosynthesis
How old is a rock?
Radioactive decay allows us to do radiometric dating
The amount of radioactivity present in a rock is used as a geologic clock
Rate of decay is predictable
The time it takes for half the isotope in a sample to break down is called half-life.
Younger rocks lie on top of older rocks
Rocks normally form relatively horizontal layers
The Great Oxygenation Event (GOE)
The world with no oxygen had green seas with an orange sky
Dissolved iron in the sea is where life rose
Certain bacteria found a way to split water apart during photosynthesis, generating O2 waste
These cyanobacteria are called Stromatolites.
Iron banding in mountains was formed by sudden exposure to oxygen, making it layers of iron and iron oxide v v
Photosynthesis by cyanobacteria caused the GOE
We are the descendants of organisms that survived the GOE
Mass extinction and the course of Evolution:
We see patterns in the fossil record: extinctions followed by adaptive radiation
Punctured equilibrium: Periodic bursts of species change as a result of sudden environmental change
Continental Drift and Evolution
Why are marsupials found in Australia and the Americas but nowhere else?
Plate tectonics
movement of Earth’s upper mantle and crust
Influences the geographical distribution of landmasses and organisms
Causes continental drift: the movement of the continents relative to one another
Taxonomy
Systematically identifying, naming, and classifying organisms based on the basis of shared traits
Convergent Evolution - Organisms that are not closely related but evolve similar adaptations as a result of independent episode of natural selection
Look similar but aren’t closely related. Ex: Flying squirrel vs Sugar glider
Analogy vs Homology
Analogy - Similar structures but not shared ancestry
Homology - Shared ancestry and similar structures
Multicellular Organism
Cells communicate, stick together, work together, depend on each other
Plasmodesmata - Bridge between cells, serves as a communication between cells
What is an Animal
Multicellular eukaryote
Heterotroph
Obtains nutrients by ingesting other organisms
3 Symmetries
Asymmetrical - no defined shape, Simple living animals, lack tissue/organs
Radial Symmetry - symmetrical in all directions, Circular body, no clear right or left
Bilateral Symmetry - Mirror image of left and right side, Mirror clear left and right, adaptation for seeking food, prey, and avoiding predators
Protostomes and Deuterostomes
Most animals are Protostomes
Deuterostomes
Animals with bony or cartilaginous backbone
Chordates (common mammals like dogs, humans, etc)
Protostomes
Mollusks - Soft bodied invertebrates, usually hard shell slugs, snails, clams
Annelids - Segmented worms
Arthropods
Most abundant invertebrates
Segmented body, jointed appendages, hard exoskeleton
Includes Insects
First animals to live on dry land
Chordates all MUST have…
Dorsal, hollow nerve cord
A notochord
Pharyngeal slits
Post-anal tail
Differences in Fish
No Jaws - Lampery, Hagfish
Jaws - Ray-finned fish, Lobe-fish, Shark
Chordates that are not Vertebrates
Lanclets
Tunicates
Vertebrates - an animal of a large group distinguished by the possession of a backbone or spinal column, including mammals, birds, reptiles, amphibians, and fishes.
Heterotroph - an organism deriving its nutritional requirements from complex organic substances.
Cyclostomes - Hagfish and Lampreys. Are chordates but are JAWLESS. Both circular mouths
3 Lineage of Jawed Fish
Chondrichthyes - No lungs, Made of flexable cartilage, no bones
Ray-finned fishes - Have lungs (most abundant vertebrate group)
Lobe-finned fishes - Have lungs, Lungfish, tetrapods
Only “finned” fishes are bony vertebrates, Lamprays and Chondrich arent but are vertebrates, and Hagfish has no backbone at all so they are not vertebrates
Challenges for Life on Land
Mass and Structural support
Locomotion
Air breathing
Feeding
Sensory
Water balance
Reproduction (From Eggs, to birth relying solely on parent, to developed placenta
Amphibians - The first vertebrate tetrapod able to move on land. Ex: Salamanders, Frogs
Land Adapted Tetrapod Egg, The Amniotes:
A private pond for the embryo to grow. Can survive on land
Mammals do not do this
Birds are closest relative to Dinosaurs and evolved from a lineage of two legged dinos called Theropods
What is a Mammal:
Key features
Sweat glands
Mammary glands
Hair
Four chambered hearts
Reproduction in Mammals:
Monotremes - Echidnas and Platypus lay eggs, and have sprawling legs
Marsupials - Young born early, carried in pouch until development. Most are in Australia and south america (Kangaroo) (Opossum)
Eutherians - Placentas, more developed at birth than Marsupials (Humans, Giraffes)
Plants:
Non Vascular - No vascular tissues, small and low. Ex: Thalloid, Liverwort
Ferns - Vascular, No seeds, Ex: Shuttlecock fern
Gymnosperms - Vascular, Seed-producing in cones Ex: Brazilian Pine
Pollination by only Wind
Angiosperm - Vascular, Seed-producing in Fruit Ex: Amazon Rubber Tree
Pollination by Wind and Animal
90% OF LAND PLANTS ARE ANGIOSPERM
Vascular vs Non Vascular
Vascular plants - have Xylem and Phloem, Roots, Grow tall, Life cycle DOES NOT depend on water (Flowers, Ferns, Conifers)
Non Vascular plants - No Xylem and Phloem, Short, no roots, Life cycle dependent on water (Moss, Liverwort, Hornworts)
Moss:
Have a key feature in the sporophyte key for success in dry environments: Stomata, Cuticle
Stomata - A key feature allowing gas exchange while reducing water loss
Vascular plants have Xylem and Phloem
Transport of water and nutrients
Structural support
Lignin makes it happen
Lignin is the reason why the TALLEST MOSS WILL NEVER BE TALLER THAN THE SHORTEST APPLE TREE
Polymer to remember
Ferns:
Most are terrestrial
Few aquatic (lillypads)
Large leaves with branching vascular strands
Reproduces by spores (Difference between moss and ferns is Ligin and being a vascular plant)
How are Frogs and Seedless Plants similar?
Sperm must swim through water to fertilize eggs, Seedless plants and Amphibians are not “Fully” terrestrial reproduction. Its not free from water
Gymno vs Angio sperm
Gymno - Cones
Angio - Flowers, Fruits, Seeds
Types of Angiosperms (Clades)
Monocots - One cotyledon (inside seed), includes grass, lillies, orchids
Eudicots - Two cotyledons (inside seed), mostly herbs (nonwoody), Vines, Trees, shrubs
Monocot Clade, Poaceae - The Grasses
70% of ALL CROPS are grasses
All the parts of a flower are modified leaves (WILL BE ON EXAM)
Stamens bear microsporangia: filament and anther
Carpels bear megasporangia: Pistil, stigma, style, overy
Petals - Inner whorl, collectively the corolla
Sepals - Outer whorl, collectivly the calyx
Carnivorous Plants
Get all nitrogen/phosphorous by consuming small animals or microbes
Myco-heterotrophy - A plant obtains some or all of its energy by parastism of fungi
Fungi:
Single celled or multicellular
Cell walls made of Chitin
Absorbative heterotroph (NO PHOTOSYNTHESIS)
Absorbs digestive food, excretes digestive enzymes
Modes of Nutrients
Saprobes - Feeds on non living
Parasitism - Gets nutrients from a host
Mutualist - Both individuals benefit
Fungi are very important
They decompose cellulose, lignin, and keratin
Carbon cycle relies on this decomposition
Saprobic fungi return carbon to the atmosphere
Multicellular Fungi
Body is mycelium (under soil) - composed of tubular filaments called hyphae
Chytridiomycota
Only fungal group with flagellated cells (sex cells) as part of its lifecycle
Strictly parasitic or saprobic
Only fungus with true alterations in generations
Asexual reproduction uses Zoospores (thin walled), clonal
Sexual reproduction with sporangia (thick walled), spores germinate into multicellular gametangia
Chytridiomycosis — affects amphibians, sporangium on skin surface (
2 Mycorrhizal Associations
Endomycorrhiza
Penetrates root cell wall
Symbiotic
Ectomycorrhiza
Does not penetrate root cell wall
Symbiotic
Lichens = Fungus + Photosynthesizer
Mutualistic association with photosynthetic organism (eukaryote or cyanobacteria)
Highly sensitive to air pollution
Different types have different sensitivities to Sulphur dioxide gases
3 Main Types - Crusty (High SO2 concentration), Leafy (Medium SO2), Shrubby (Low SO2)
Pathogenic Fungi
A major cause of death in people with compromised immune systems
Fungi can cause other human illnesses like athletes foot and ringworms
Microbial Diversity:
Too Small to See
Van Leeuwenhoek was the first observer of microbes
Ribosomal RNA - Sequence in the ribosomes is conserved — it does not change much over tine
Methanogens - Chemical oddities in microbial world
Killed by oxygen
Produced unusual enzymes
Cell walls different from all known bacteria
Clearly not bacteria
Only a small amount of microbials have been studied
Only Microbes like bacteria and archaea can free N2 from the atmosphere
Nitrogen fixation in plants:
Mutualism of some bacteria with the roots of some plant species
Most chemical cycles are dependent on microorganisms
Sulfur, Carbon ,Water, Nitrogen cycles
Extremophile Microbes - Microbes that live in extreme environments (hot springs)
Many Archaea produce or consume Methane
Many live in the guts of grazing mammals, termites, and cockroaches
The Microbiome: All the microbes that live in or on your body
Disruption of microbiome can lead to bad health or sickness
Gut bacteria, B12 and K
Microbiome source:
Birth
Breastfeeding
Diet
Fiber is crucial for a healthy microbiome diversity
Microbiomes form huge multicellular mats
Spirochetes - 6 genera of great impact
Gram negative, motile bacteria
any of a group of spiral-shaped bacteria
Best studied are human parasites, herbivore symbionts
Oomycetes - the water molds and downy mildews
Water molds are absorptive heterotrophs; organic matter
Saprobic - Feeds on dead
Dinoflagellates - Mostly marine plankton, mostly photosynthetic, important producers, may be parasitic or predatory
Diplomonad - “Two units” ; “double celled”
No functional mitochondria; reduced structure for other pathways
Waterborne parasite that causes intestinal disease
Conservative Biology: (Last content in Final Exam)
Biodiversity
Species
Keystone species, removal of keystone results in lower species diversity
Genetic
Microevolution
Changes in Allele
Ecosystem
Trophic cascade
Numerical - Control the numbers (abundance, biomass )
Behavioral - Control the behavior (feeding rate, activity)
Extinction is common, but is usually balanced with speciation (1 species splits into 2)
Biologist believe we are amidst a 6th mass extinction with how high the rate of extinction is today
Restoration may include several techniques
Removal of pollutants or non native species
Revegetation
Reintroduction of native species
Reestablishment of hydrological processes or disturbance regimes
Nature reserves based on Ecological Principles:
One big area is better than multiple separate areas that combine to be the same size
A reserve with a buffer zone is better than one without a buffer zone
Reserves that are connected by habitat corridors are better than unconnected reserves
Coupled Human-Natural system ecology - Peregrine falcons use human urban settings to build a nest mimicking cliffs
Wildlife Intrinsic Value - Ecosystem Services (financial aspect) and Connectedness
What about Organisms that don’t have measurable value or importance
Intrinsic Value - Value simply by existing (culturally, religious, memories). Beautiful animals, good to know exists
Pressures on Biodiversity
Habitat Loss and Degradation
Cutting down timber, about 50-60% of land surface has been altered by this and grazing
About 2-3% has been altered by cities and utilities
Overharvesting of Biological resources
Species Invasions, disease, pollution
Climate alteration
Habitat Fragmentation - Secluded habitats leading to lack of diversity in population Ex. NYC park
Species Invasions
Can cause change in ecosystem function
Native Species - Naturally occurring in area
Non Native Species - Not Naturally occurring, but cause no harm
Invasive Species - Not naturally occurring AND cause harm to the system
Toxic Pollutants
Nondegradable plastic garbage
Broken up into small pieces and when ingested by marine animals, its a choking hazard or disrupts endocrine functions
Climate Change
Rapid warming is changing the global climate
Can cause growth of disease Ex. Lyme disease in deers from ticks, Flesh-eating bacterium like Vibrio in more northern locations
Weather vs Climate
Weather - Short term atmospheric conditions. Temp, precipitation, and other data at a point in time
Climate - Long term atmospheric conditions, averages that describe many weather data points. Climate required careful calculations because it includes A LOT of weather data
Climate Change and Global Warming (Event and Cause)
Climate change - When there is a change in climate over an extended period of time
Effects include: Changes in avg. temperature, seasonal behavior of plants and animals like flowering dates
Global Warming - Major cause of current climate change
Changes in Phenology
Spring temperatures have risen over the past 25+ years, in result of that plants flower earlier
Roe deer birth has not changed enough to compensate for changing schedule, this is associated with a decline in young roe deer survival. (Deer are not timing based reproduction with a food source)
Phenological changes lead to Mismatch - A disruption in the timing of natural events between different species that rely on each other
Effects of Climate Change
Extreme wildfires affects many ecosystems Ex. Australia in 2019
Recent climate change lead to
More frequent and more extreme wildfires
Quicker loss of moisture in soil
Reduced defense of trees against bark beetles
Warming Up
Greenhouse effect
Sunlight hits Earth’s surface
Sun energy creates heat
Some heat escapes out of the atmosphere
Some heat remains in the atmosphere trapped by greenhouse gases such as CO2 and methane
Increased with Industrialization
Rising temps caused Artic sea ice to melt and break apart
Northern pole (Artic) saw the highest temperature raise
Carbon Cycle
Plants absorb carbon dioxide and convert it into solid form
Organisms return some carbon dioxide into the atmosphere
Other carbon is buried, fossilized, and some converted into coal, oil, and gas over very long time scales
The amount of CO2 produced from natural processes and the amount absorbed through photosynthesis are similar
CO2 produced by human activity makes a net increase in atmosphere CO2
CO2 Measurement
Historically - Gas bubbles trapped in artic ice
Modern - Directly from air
CO2 has been steady for hundreds of thousands of years, but is at an all time high post industrialization
Pros and Cons for Nonrenewable resources
Pros - Cheap and Abundant
Cons - Extracting damages ecosystems, burning causes climate change and health issues
Pros and Cons for Renewable resources
Pros - Source that isnt depleated, Less CO2 released
Cons - Expensive, can modify physical environment causing damage, some produce hazardous waste