Biotic potential:
The ability of organisms to reproduce and survive
Most insects have a:
High biotic potential
R-Selected species:
- Smaller organisms
- Many offspring
- Little prenatal care
K-Selected species:
- Larger organisms
- Fewer offspring
- More prenatal care
R-Selected species (On growth curve chart) represents:
Maximum capacity to reproduce (described: population sizes over time in relation to carrying capacity)
On the growth curve the R-Selected species...
Population sizes over time in relation to carrying capacity: shoot well above (highly fluctuate) and below; exponentially (or skyrocket)
K-Selected species (On growth curve chart) represents:
Carrying capacity (described: population sizes over time in relation to carrying capacity)
On the growth curve the K-Selected species...
Population sizes over time in relation to carrying capacity:
go above and below carrying capacity; slightly
Growth Curve chart *hint:
R = Really high
K = Kind of high
Carrying capacity:
The maximum population size of the species that can sustain indefinitely
Traits:
Characteristics of an organism that are expressed by genes and/or influences by the environment
Some _____ already exist in a pop's gene pool/become more or less frequent over time
Traits (ex: eye, skin, hair color)
Where do 'new' traits come from?
Genetic mutation
Genetic mutation:
A natural process that occurs every time there's genetic replication (reproduction) They produce genetic varability
Genetic mutations produce...
Genetic variability
Adaptation:
Any trait (physical form, function, or behavior) that helps an individual to survive and reproduce w/in their environment
What determines whether a mutation is considered beneficial or harmful?
If the organism survives w/ the mutation just as well as before, or even better then it is beneficial; if the opposite case occurs it is harmful
Mutations w/in genes can produce changes in form or function of that gene causing _____
Variation
Between genes the effects are minimal and most often cause...
No change to the individual
(SAMPLE ESSAY ?)
What influence does high biotic potential have on the appearance of 'new traits' & rate of adaptation?
High biotic potential = an increased mutation rate;
increased opportunity for beneficial mutations;
beneficial mutations = an increased rate of new traits;
increased rate of new traits = an increased rate of adaptation.
Natural selection:
Those organisms BEST fit to exist under the CURRENT CONDITIONS, SURVIVE, and produce more OFFSPRING
Best fit:
Combination of genetic material that gives an organism an advantage over others in the population
Factors contributing to 'current conditions' can be:
A-biotic or biotic
Abiotic:
Non-living factors (temperature, precipitation, wind, sunlight...)
Biotic:
Living factors (predation, disease, mating...)
There are traits whose sole function is to:
Help maximize reproductive success
What are the forms of natural selection in nature?
Directional, stabilizing, disruptive
In what scenario would male African elephants be found w/ very large tusks and very small tusks?
Disruptive selection
What is Directional selection?
A directional shift in the frequency of the mean value of a trait as a result of current conditions
When a favored trait is at one end of the range of traits (leads to distinct changes in the frequency)
Directional selection example:
Giraffes - OG trait: shorter necks; eventually shifted for feeding purposes
Giraffes w/ longer necks could reach the food so they survived better and passed down the longer neck trait
What is Stabilizing selection?
Where the population mean stabilizes on a particular trait value, and selection pressures eliminate the extreme values of a trait from a gene pool
Selects against extreme phenotypes and instead favors the majority that are well adapted to the environment
Stabilizing selection example:
Human baby - OG trait: birth weight; smaller babies have a hard time defending themselves from infections, staying warm, etc & larger babies are difficult to naturally deliver
So, survival weight for babies has been higher for those in the middle weight r
What is Disruptive selection?
Where the extremes of a trait are advantageous and the average values are selected against
When the environment favors extreme traits at both ends of the spectrum while selecting against common traits
Disruptive selection example:
Organism: Salmon - medium sized fish get outcompeted or territory by larger fish, smaller fish are able to sneak in and fertilize eggs before being detected
Therefore, largest/smallest salmons survive the best and NOT medium sized fish
(SEE GOOGLE DOC) Which image shows directional selection?
1
(SEE GOOGLE DOC) Which image shows stabilizing selection?
2
(SEE GOOGLE DOC) Which image shows disruptive selection?
3
Sexual selection:
A special form of natural selection involving traits whose sole function is to help maximize reproductive success
What are the two main forms of sexual selection?
- Female choice
- Male competition
Female choice:
The females wants some of the males desirable traits for their own offspring
Male competition:
Males 'fight' to 'win over' or impress the female
Female choice example:
Female birds often choose males based on elaborate ornamentation and behavior
Male competition example:
Elephant seals fight each other for the best mating spot (alpha male in center/beta males of to the side center away from them/peripheral males on the outskirts, not as likely to reproduce that season)
What's the relationship between natural selection and sexual selection?
Natural selection is taking place (usually always)
Camouflage (crypsis):
An organism's ability to hide itself from predators or prey. Two common types are: background matching & disruptive coloration
Background matching example:
Octopus hidden on the sea floor waiting for prey
Disruptive coloration example:
Zebras standing in a herd is difficult to look at/focus on for predators
Background matching:
A form of camo where colors and patterns blend w/ a specific background. Works best for organisms that spend majority of their time in a specific habitat
Countershading:
2+ color variations on the body (these are most common in areas where sunlight is a factor)
Countershading example:
Penguin - dark back to blend, light/yellow bottom so predators looking up from lower in the water can not see them
Disruptive coloration:
A form of camo that works by breaking up an organism's body outlines. More characteristics of organisms spending time in multiple habitats (motion dazzle / dazzle camo; bold patterns cause a misrepresentation of the true speed/direction)
Mimicry:
A form of camo where the colors and patterns are intended to be seen. This typically involves 2 or more different species, and the mimicry benefits one or both organisms
Mullerian mimicry:
2 or more poisonous species closely resemble each other. Often due to presence of a similar predator
Mullerian mimicry example:
Viceroy vs. Monarch butterfly, viceroy mimics monarch to avoid predators; even though they're BOTH poisonous, looking the same in the same environment ultimately reduces predation rates on them
(EX: 15% predation rate to both species (divide by the 2 spec
Batesian mimicry:
Where the evolution of a species results in the development of traits suggesting the species is 'dangerous' but it's not. It is mimicking a poisonous or toxic species
Batesian mimicry example:
Hoverfly vs. Yellow jacket wasp � may have originally been caused by a possible genetic mutation (i.e. body segments or color) overtime the hoverfly has mimicked the wasp/looks more like it now/shows predators they're 'posionous'
(EX ESSAY ?) Explain the process of 'how' the hoverfly has evolved to take on the appearance of the yellow jacket wasp...
Hoverflys have evolved overtime to take on the appearance of a wasp through their history of mimicking.
This mimic may have occurred due to a past genetic mutation of some sort that could have caused for their body segments or colors to change over time.
How does batesian mimicry happen?
If there's already genetic variability in the population, the process of natural selection will then gradually dictate which traits are BEST FIT.
If there was NOT genetic variability in the population, then a 'new' trait could have arisen from genetic mut
Evolution:
The change over time in a pop's genetic makeup (gene pool) through successive generations
Mechanisms (of evolution):
Genetic mutations and natural selection acting on the genetic variability w/in a pop
When do genetic mutations take place?
At conception
When does natural selection occur?
After birth
When does evolution take place?
After successive generations; only to populations NOT individuals
Bacteria evolution:
Some double every 20 minutes (primary reproduction: asexual)
Asexual reproduction:
Doubling/clone
Sexual reproduction:
Conjunction (where new genetic variations can come to be) exchange data
Bacteria evolution example:
Hand sanitizer (antibiotic resistance; return to full strength after 3 hours) The bacteria's DNA changes to become more resistant to certain toxins or chemicals � antibiotic resistance
What is antibiotic resistance and how does it develop?
The overuse of antibiotics � especially caused by taking antibiotics even when they're not appropriate treatment � promotes antibiotic resistance
(EX ESSAY ?) Describe the process of HOW antibiotic resistance develops in bacteria...
As DNA is copied very rapidly, errors in the copy (mutations) frequently occur.
W/ such a high # of mutations, some of these copy errors can result in resistance of antibiotics, those will be the only bacteria to survive. Considering that they are able to
Fossils allow us to look into the past and answer questions about...
Earth's geological history, past climates, distribution of plants/animals, and help answer questions about evolutionary pathways.
(EX ESSAY ?) List & explain (what evidence do they provide) the scientific evidences for evolution...
- Fossil records (missing links and transitional fossils) *Key fossil records that help to explain evolutionary pathways
- Organism morphology
- Developmental biology
Organism morphology:
The study of the structure, form, and function of traits *by comparing similar structures on animals we can observe, we can learn about those we couldn't (ex: dinosaurs)
Developmental biology:
Many vertebrate animals share a very similar embryonic stage
Co-evolution:
Process whereby the evolution of one organism DRIVES the evolution of another
Co-evolution example:
Acacia tree/Acacia ants
- Tree provides home for ants (in thorns)
- Tree provides (addictive) sugary food - nutrient filled food source (specifically created for the ants)
- Ants provide protection for the tree (attack anything that comes near) won't let
How did the Acacia tree/ant relationship evolve?
Genetic variability (possible mutations) / natural selection leading to adaptations / leading to evolution
(EX ESSAY ?) Draw 2 different (brand new) species & demonstrate co-evolution in a drawing
*COPY ACACIA TREE/ANT EXAMPLE BUT CHANGE:
ants --> new butterfly species
tree --> new flower species
Convergent evolution:
The process where unrelated organisms develop similar adaptations best suited for living in similar environmental conditions. These species developed similar traits to access food (energy)
Species that are NOT related but they all end up looking like each
Convergent evolution example:
Shark, dolphin, extinct ichthyosaurus (they all look very similar; dorsal fin, pectoral fins for stability, but are NOT related)
Symbiosis (symbiotic relationship):
2 different species that live together (temporarily or prolonged) where at least 1 organism benefits (3 types: mutualism, commensalism, parasitism)
Mutualism:
(+,+) Both organisms benefit
Mutualism example:
Acacia tree and ant (both benefit)
Commensalism:
(+,0) One benefits, the other does not, but is not harmed
Commensalism example:
Barnacles attached to whales (whale does not benefit/ is not harmed; barnacles gather food and migrate w/ the whale)
Parasitism:
(+,-) One benefits the other is harmed
Parasitism example:
Parasites / Parasitoid
Parasites:
Organisms that are harmful to another organism, but do not kill the host (ex: crabs or lice)
Parasitoids:
Parasites that ultimately kill the host (ex: several species of parasitic wasps lay eggs on or w/in the larvae of other insects � ultimately killing them. ex 2: strangler fig on trees)
Most important conservation issue today:
Invasive species
Native species:
A species belonging to a region as a result of only NATURAL PROCESSES w/ no human intervetion
Non-Native species (aka exotic, alien, introduced, non-indigenous):
A species living outside of its native range, which has arrived there by HUMAN ACTIVITY, either deliberate or accidental
Invasive species:
Any non-native organism (plant, animal, fungi, bacteria, etc) that adversely impacts the regions they invade
Impacts of invasive species:
- Natural resources & environmental (biodiversity, ecosystem structure, function...)
- Human health (social/public health, happiness, cultural values...)
- Economical
Impact of invasive species example:
Japanese weed plant could potentially hurt:
- human health (ex: cause stress, or labor to take down)
How invasive species become introduced:
1. Natural invaders (ex: cattle Egret, native to Africa)
2. Intentional (takes animals and puts them in other places for economical, cultural, or etc reasons)
3. Inadvertent or accidental
How ecosystem goods/services are affected...(Cattle Egret example)
They follow livestock and eat the stirred up insects from the farming (eating both beneficial and bad insects) Also harmful b/c they can eat the farmers newly purchased and planted seeds
Gause's Principle:
No 2 different species can occupy the identical niche for any significant amount of time. If this occurs...
1. Competition drives 1 species out of the area
2. Competition causes 1 species to become extinct
3.If the species stays, it must adapt and evolve