Exam 2: Evolution, Classification, and Diversity unit

Population

A group of organisms of the same species living in the same area.

Variation

Differences in inherited traits among individuals within a population

ex: some members of a population have different inherited colors

Natural selection

Individuals with advantageous inherited traits tend to survive and reproduce more successfully. (Requiring heritable variation)

Adaptation

An inherited trait that increases an organism's fitness in a particular environment.

Example: A trait that helps an organism obtain food and produce offspring.

Evolution

A change in allele frequencies in a population over generations.

Charles Darwin:

Developed ideas about evolution after observing organisms during his voyage on the HMS Beagle and the ship aboard that influenced his theory of evoltion

Alfred Russel Wallace:

A naturalist who independently developed similar ideas while studying organisms

The 3 different principles of nature:

1. Variation: Individuals differ from one another

2. Inheritance: Variation is passed from parent to offspring

3. Competition: Not all individuals survive

Fossils

Remains or impressions of ancient organisms that support evolution by showing change in organisms over time.

Anatomy

Body structures help reveal relationships

Embryology

Similarities in early development suggest common ancestry

Biogeography

Geographic distributions provide evidence of common ancestry

Molecular biology

DNA and biochemical similarities help show relationships

Homologous Structures

Anatomical structures that indicate shared common ancestry.

They may have different functions.

Analogous Structures

Anatomical structures that share similar functions but result from convergent evolution rather than common ancestry.

evolved independently through convergent evolution.

Vestigial Structures

Nonfunctional remnants of ancestral traits that provide evidence of evolutionary history.

Reduced or leftover features

Evolution is just a theory

In science, a theory is a well-supported explanation, not simply a guess.

Individuals evolve

Evolution is measured as changes in populations over generations.

Evolution explains the origin of life

Evolution explains changes in living populations; the origin of life is a separate question.

Organisms evolve on purpose

Evolution is not a process in which organisms deliberately develop the traits they need.

Biological species concept:

A species is a group whose members can interbreed and produce fertile offspring.

Allopatric speciation:

Populations become geographically separated or speciation that involves isolation between populations

Sympatric speciation:

New species form without geographic separation, in the same area or speciation that occurs within the same geographic area

Hardy-Weinberg Equilibrium

1. Large Population

2. No gene Flow

3. Random Mating

4. No Mutation

5. No Natural Selection

The Allele Frequencies remain constant

Isolation

It is the trigger that stops gene flow; groups can’t mix or stay the same

divergence

The process, mutations, drift, and selection change each group over time

Speciation

As a result, the group becomes different; they can no longer interbreed, even if the wall is removed

Gene Pool

Alleles in a population

Allele

A version of a gene

Allele frequency:

proportion of a particular allele in a population.

Equilibrium population

Population whose allele frequencies remain unchanged across generations under the specified conditions.

Evolutionary fitness

How successfully an organism contributes offspring to future generations.

Mutation:

A change in DNA and the ultimate source of new genetic variation.

Genetic Drift

Random fluctuations in allele frequencies that have the strongest evolutionary effects in small populations.

• Founder effect: A small group establishes a new population, carrying only some of the original population's variation.

• Bottleneck effect: A population is drastically reduced, leaving a smaller and potentially less genetically varied group.

Gene Flow

The movement of alleles between populations resulting from individual migration.

Early Earth's Atmosphere

The primitive atmospheric condition of Earth, which likely lacked oxygen (O2​).

Miller-Urey Experiment

A landmark laboratory experiment that demonstrated organic molecules can form abiotic conditions simulating early Earth.

Cyanobacteria

Performed photosynthesis and released oxygen, changing Earth's atmosphere and allowing oxygen-dependent life to develop.

aerobic respiration and helped create conditions that supported the evolution of more complex life.

The Earth

4.5-4.6 billion years ago

First Life: PROKARYOTES

3.5 billion years ago

Photosynthesis and Oxygen

2.2 billion years ago

First EUKARYOTIC CELLS

2.1 billion years ago

First animals

500 million years ago

First land plants

500 million years

Stereoscopic/binocular vision

Using two eyes to perceive depth

Hands

Grasping and manipulating object

Increased Brain Capacity

An evolutionary advancement in Homo sapiens linked to the development of culture and language.

Bipedalism

The evolutionary adaptation of walking upright on two feet in human ancestors, closely associated with tool use.

Tool use

Using objects to accomplish tasks

Three common bacterial shapes

Coccus

Round

Bacillus

Rod-shaped

Spirillum

Spiral-shaped

A prion is

an infectious misfolded protein; it is not a bacterium or a virus.

NO DNA or RNA

Binary Fission

A form of asexual reproduction and cell division commonly observed in prokaryotes.

Conjugation

A bacterial process involving the direct transfer of DNA between two interacting cells.

Microbiome

Community of microorganisms in a particular environment

Nitrogen-Fixing Bacteria

Specialized bacteria that convert atmospheric dinitrogen (N2) into ammonia (NH3).

Decomposers

Break down dead material and recycle nutrients

Bioremediation

Use organisms to help remove or break down pollutants

Biofilms

Surface-attached, structured communities of bacterial cells.

Clostridium

A bacterial genus specifically listed in your objectives; study its course examples

Pathogen

A disease-causing agent

Protists

a diverse group of eukaryotic organisms that are not classified as plants, animals, or fungi.

Diatoms

A group of photosynthetic, autotrophic eukaryotic protists.

Plasmodium

A genus of parasitic protists responsible for causing malaria.

A pathogen can be a bacterium, but not all bacteria are pathogens.

Some bacteria cause disease, while others are harmless or beneficial. Your microbiome and nitrogen-fixing bacteria objectives are reminders that microorganisms can play useful roles.

Dinoflagellates

Associated with red tides in the objectives

Red algae

• Produces carrageenan, a gel-like polysaccharide.

• Used as a thickener in ice cream, jelly, salad dressing, and lunchmeat

Green algae

• Examples: Spirogyra and Ulva.

• Can be multicellular.

• Land plants probably evolved from green algae.

• Can be grown for biofuel.

Mycelium

The vegetative feeding network of a fungus, composed of threadlike filaments called hyphae.

Hyphae

Thread-like structures that make up much of a fungus.

Fruiting body

A reproductive structure that produces or releases spores in many fungi.

Penicillium

A genus of fungi widely known for its importance in antibiotic production.

Claviceps purpurea (ergot)

Specifically listed in your objectives, review its effects from the lecture

Yeasts

Fungi that include single-celled forms

Mycorrhizae

Mutualistic symbiotic association between fungi and plant roots

Lichens

A fungus living with a photosynthetic partner

How plants adapted to life on land

• Waxy cuticle: Helps prevent water loss.

• Vascular tissue: Transports water, minerals, and sugars through the plant.

Vascular

ferns

Have vascular tissue for transport but reproduce by spores rather than seeds.

gymnosperms

Seed plants that generally produce exposed seeds, often in cones.

angiosperms

Flowering plants that produce seeds enclosed within fruits.

Nonvascular

mosses

Lack the specialized vascular system found in vascular plants.

Xylem

Vascular tissue in plants responsible for transporting water and dissolved minerals.

Phloem

Vascular tissue in plants responsible for transporting sugars throughout the plant.

Monocots

• One cotyledon in the seed.

• Flower parts often occur in multiples of three.

• Leaves often have parallel veins.

• Roots commonly form a fibrous system.

• Stem vascular bundles are commonly scattered.

Dicots

• Two cotyledons in the seed.

• Flower parts often occur in multiples of four or five.

• Leaves often have branching, net-like veins.

• Roots commonly form a taproot system.

• Stem vascular bundles commonly form a ring.

Meristem cells

are plant cells responsible for growth and cell division.

They occur in regions where plants grow, including:

• Apical meristems: At root and shoot tips; contribute to growth in length.

• Lateral meristems: Contribute to growth in thickness, including the vascular cambium.

Transpiration Water Loss Rate

The biological proportion of absorbed water lost by plants via transpiration, amounting to about 90%

Transpiration

The evaporative loss of water vapor from plant surfaces, primarily occurring through stomata.

plant hormone

a chemical signal that regulates plant growth or development.

Plant Hormones: Auxins

Plant hormones that promote cell elongation and stem curvature toward light.

Plant Hormones: Ethylene

A gaseous plant hormone that promotes fruit ripening.

gibberellins

Growth upwards/ germination where the seed spore or pollen grain wake up

Culture (Evolutionary Advantage)

An adaptive capacity in Homo sapiens that enhances survival through the intergenerational transmission of learned behaviors.

Annual Rings

Concentric rings in secondary xylem formed due to seasonal differences in plant growth rates.

Vascular Cambium

A plant lateral meristem that produces secondary xylem and secondary phloem during secondary growth.

Chytrids

A group of aquatic fungi notable for infecting and harming amphibian populations.

Archaea

A domain of unicellular prokaryotes distinguished from bacteria by unique membrane chemistry and genetics.

Eukarya

The cellular domain characterized by organisms possessing a membrane-bound nucleus and organelles.

zoonotic Diseases

Infectious diseases that are naturally transmitted from animals to humans.

Fitness

The measure of an organism's evolutionary success, determined by the number of fertile offspring produced.

Embryological Similarities

Shared developmental structures in early embryos that indicate common ancestry among diverse species.

Stabilizing Selection

A mode of natural selection that favors intermediate phenotypes over extreme variations.

Galápagos Finches

A classic biological example of adaptive radiation observed in the Galápagos Islands.