Evolution by Natural Selection Flashcards

Flashcards from Evolution by Natural Selection Lecture Notes

Evolution

Change in the gene pool of a population over time.

Population

All the organisms of a particular species living in the same place at the same time.

Gene pool

All the alleles of all the genes in a species or population.

The Origin of Species (1859) challenged the notions that:

Species are independent (unrelated), Life on Earth is young (~ 6000 years old), Species are immutable (incapable of change)

Darwin and Wallace Model of Diversity of Life

Change through time + common ancestry

Natural Selection

differential reproduction based on heritable traits

Requires a varied population

Biological fitness

The ability of an individual to produce surviving, fertile offspring relative to that ability in other individuals in the population

Tuberculosis (TB)

The bacterium Mycobacterium tuberculosis causes TB, TB infects the lungs, often causing death

Natural Selection:

Differential reproduction based on heritable traits

Biological fitness

The ability of an individual to produce surviving, fertile offspring relative to that ability in other individuals in the population

Fossils

Imprints or remains of organisms that lived in the past

The Fossil Record

The ordered sequence of fossils as they appear in rock layers

Reveals the appearance of organisms in a historical sequence

Biogeography

Species in the same area tend to be more closely related to one another

Homologies

Similarities due to shared ancestry

Structural homologous

Similarity in morphology

Some ancestor was the first to have this bone we inherited it

Reveals vestigial traits Requires

Tiktaalik rosae

Ancestor of all Tetrapods? Its fins show the beginnings of elbow and wrist-like features

Developmental homology

Observed in embryos

Genetic homology

Number of DNA nucleotide base differences in the cytochrome c oxidase gene

Partial Pressure

The pressure of a particular gas in a mixture of gases

Oxygen makes up 21 percent of the atmosphere but its partial pressure depends on evolution

Ventilation

Movement of air and water through a specialized gas exchange organ such as the lung or gill

Diffusion at the respiratory surface

Where O2 moves from the air or water into the blood and CO2

Diffusion at the tissues

Where O2 moves from the blood into the tissues and CO2 moves from the tissues into the blood

Cell respiration

Cells use of O2

Gills

Aquatic organisms

Must be very efficient because dissolved 02 is lower in water than in air

Trachea systems

Air tubes that branch throughout the body connected to pores in the exoskeleton known as spiracles

Inhale and exhale

Lungs

Vertebrates

Offer a large thin surface area for gas exchange between air and blood

Negative pressure

Longs expand and contract in response to changes in pressure inside the chest cavity

Positive pressure

Buccaneers pumping

Lower the pressure in the throat

Air moves through nostrils and into the oral cavity

Closes nasal passages and constricts throat

Transportation

O2 and CO2

Regulation

Transportation of hormones

Protection

Blood clotting

Precapillary sphincters

Can allow or limit blood flow

Arteries

Use blood pressure to move blood