10TH GRADE BIOLOGY - EVOLUTION

limiting factor

Any factor (biotic or abiotic) that restricts the existence of organisms in a specific enviornment.

Bottleneck

Any kind of event that reduces the population significantly. (examples: earthquake, flood, disease...)

Sexual reproduction

results in variation of traits in offspring as a result of crossing over in meiosis and mutations

Evidence for Evolution

1. Common ancestry 2. Homologous structures 3. Embryo Development 4. Vestigial Organs 5. Fossils

Causes of mutations

1. DNA fails to copy accurately. 2. External influences (ex. exposure to chemicals)

Post Darwin Beliefs

1. Earth is billions of years old. 2. The planet has changed and organisims have changed as well (found through fossils)

Pre-Darwin Beliefs

1. Earth was only a few thousand years old. 2. Neither the planet nor species that inhabited earth had changed since the beginning of time

2 types of genetic drift

1. Founder effect 2. Population bottleneck

4 steps of natural selection

1. More offspring are produces than can survive 2. in any population individuals have variation 3. Advantageous variations survive and pass on their variations to the next generation 4. Over time, offspring with advantageous variations make up most of the population.

The range of effects of germ line mutations

1. No change occurs in phenotype 2. Small change occurs in phenotype 3. Big change occurs in phenotype

3 conditions for natural selection to occur

1. Variation must exist among individuals 2.Variation must result in differences in the number of offspring surviving 3. Variation must be genetically inherited.

Mutations

A change in DNA Example: antibiodic resistance in bacteria

Ecosystem

A community of organisms (biotic) and their nonliving (abiotic) environment

Species

A group of organisms so similar to each other that they can reproduce and have fertile offspring.

Habitat vs. Niche

A niche is determined by the limiting factor

A group of one species that interbreed and produce fertile offspring and compete with each other for resources is called

A population

mutation

A random change in the DNA of a gene.

Founder effect

A small population that branches off from a larger one. It may or may not be genetically representative of the larger population that it came from.

Genetic shuffling

A source of variation

Genetic Variation

Any change in gene (and allele) frequencies within a population or species is Evolution

Are mutations neutral, harmful or beneficial

All

population

All individuals of a species that live in an area.

Biosphere

All life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere.

Allele

An alternative form of a gene (one member of a pair) located at a specific position on a specific chromosome

predator

An animal that hunts other animals (prey) for food

Producer (all autotrophs (plants))

An organism that can make its own food.

parasite

An organism that feeds on a living host (host)

prey

An organism that is killed and eaten by another organism

consumer (all heterotrophs)

An organism that obtains energy by feeding on other organisms

Heterotrophs

An organism that obtains organic food molecules by eating other organisms or their by-products.

Niche

An organism's particular role in a community; its total way of live

In order of natural selection to occur, there must be:

At least two varieties of a species must exist.

Green plants that synthesis sugars from CO2 and H20 are

Autotrophs

Jean-Baptiste Lamarck

Believed that: 1. all organisms can change their traits during their lifetime by use or disuse. 2. Traits are passed on to offspring and over time this would cause change in a species LAMARK WAS WRONG

The highest level of organization

Biosphere

Non-random mating

Can change allele frequencies because the choice of mates is often an important part of behaviour. Plants self-pollinating is a form of non-random mating (inbreeding).

meiosis

Cell division that produces reproductive cells in sexually reproducing organisms

Charles Darwin

Credited with the Theory of Evolution & Natural Selection. Voyage of the HMS Beagle

What can cause changes in all aspects of life?

DNA

A science of relationship

Ecology

Abiotic + biotic factors =

Ecosystem

Natural selection

Environmental conditions determine which individuals in a population produce the most offspring.

What did Darwin find on his voyage on HMS Beagle

Finches on each island in the Galapagos had different types of beaks. Tortoises on each island in the Galapagos had different types of shells

What are the only mutations that matter to large-scale evolution

Germ Line mutations

Homologous Structures

If animals evolved from a common ancestor, they should share common structures

The competitve EXCLUSION principle

If two species with the same niche (role), coexist (live) in the same ecosystem, then one will be excluded from the community due to intense competition.

Two types of sexual selection

IntRAsexual selection and intERsexual selection

Two types of sexual selection

Intrasexual selection intersexual selection

Amount of water Amount of food Temperature Amount of space Availability of mates are all examples of_______

Limiting factors

What causes a inheritable change in the genotype?

Mutation

sources of genetic variation

Mutation recombination

Variation can be acted upon by natural selection because of

Mutations

What is the only source of ADDITIONAL genetic material and new alleles

Mutations

What provides the raw material for natural selection to act

Mutations

Germ Line Mutations

Mutations that can be passed on to offspring. They occur in reproductive cells.

When nature "selects" which organisms will be successful

Natural selection

Mechanisms of Evolution

Natural selection Gene flow Genetic Drift Mutations Non-random mating

recombination

New allele combinations form in offspring.

Somatic Mutations

Occur in non-reproductive cells and won't be passed to offspring.

Sexual selection

Occurs when certain traits increase mating success

Darwin's hypothesis

Organisms had a common ancestor, but had adapted to their enviornments and changed over time. He published his research in 1859

autotrophs

Organisms that are able to make their own food.

habitat

Place where an organism lives

Three types of feeding relationships

Producer - consumer Predator - prey Parasite - host

Allele Frequency

Proportion of gene copies in a population of a given allele

homologous structure

Similar structures that related species have inherited from a common ancestor.

Vestigial Organs

Structures or organs that no longer have a useful function (in humans - tailbone and appendix)

3 things that measure how fit an organism is

Survival - how long does an organism life mating success - how often it mates Number of offspring per mating that survive

heritability

The ability of a trait to be passed down from one generation to the next.

genetic drift

The change in allele frequencies by chance. Directly related to the population numbers - smaller population sizes are more susceptible because there is a greater chance that a rare allele will be lost.

gene pool

The combined alleles of all of the individuals in a population.

Variation

The difference in the physical traits of an individual compared with others of the same group.

DNA

The hereditary material of life. It affects looks, behavior and physiology.

fitness

The measure of the ability to survive and produce more offspring. A phenotype with greater fitness usually increased in frequency - most fit is given a value of 1.

Gene Flow

The movement of alleles in or out of a population (immigration or emigration).

Evolution

The process of biological change where descendants come to differ from their ancestors. Individuals don't evolve, populations do.

Artificial selection

The process where humans change a species by breeding it for certain traits.

Ecology

The scientific study of interactions between organisms and their enviornments, focusing on energy transfer

biogeography

The study of the distribution of organisms around the world

Biodiversity

The total number of different species in an ecosystem and their relative abundance.

what is the overall effect of gene flow?

To counteract natural selection by creating less differences between populations

fossil

Traces of organisms that existed in the past. Scientist can trace how a species evolved by studying them.

Population Bottlenect

When a population undergoes an event causing a significant percentage of the population

Voyage of the HMS Beagle

a 5-year voyage to South America and South Pacific, collecting specimens, making observations and keeping a scientific journal of his findings

adaptation

a feature that allows an organism to survive better in its enviornment. Adaptations can lead to genetic change over time.

A mutation in the DNA of a gene can result in

a new allele.

biotic factors

all living organisms inhabiting the earth

organism

any unicellular or multicellular form exhibiting all of the characteristics of life, an individual.

Two factors that make up the enviornment

biotic factor abiotic factor

Intrasexual selection

competition among males

Community

different populations that live together in an area (enviornment) and are interdependant (depend on each other)

What can introduce new alleles into a gene pool or change allele frequencies

gene flow

Common Ancestroy

if a species evolved from a common ancestor, they should share common anatomical traits.

the type of mutation that cause the death of an organism is called

lethals

intersexual selection

males display certain traits to females (like a peacock displaying his feathers)

Most recombination occurs during

meiosis

abiotic factors

nonliving parts of the environment (examples: temperature, soil, light,moisture, air currents)

what is the lowest level of organization

organism

analogous structre

structures that don't have a common evolutionary origin but are similar in function

what happens if a mutation occurs in the reproductive cells

the mutation can be passed on to the offspring.