Baylor University Biology 1306 Final Exam Review

key features of natural selection

- Individuals do not evolve, populations do

- Natural selection can only increase or decrease heritable traits that vary in population

homology

similarity resulting from common ancestry

homologous structures

anatomical resemblances that represent variations on a structural theme present in a common ancestor

vestigial structures

remnants of features that served important functions in the organism's ancestors

converget evolution

evolution of analogous features in distantly related groups

analogous traits

- arises when groups independently adapt to similar environments in similar ways

- does not provide information about ancestry

genetic variation

differences among individuals in the composition of their genes or other DNA segments

population

a grouping of one species in a defined area

species

individuals within a population that breed and produce offspring capable of breeding as well

alleles

different forms of the same gene

gene pool

all the genes and alleles in a population

microevolution

refers to changes in genes and allele frequencies in a population

macroevolution

the broad pattern of evolution above the species level

factors of microevolution

natural selection, genetic drift, mutations, gene flow

adaptive evolution

natural selection is aka

genetic drift

measure of changes in the gene pool in small populations

types of genetic drift

bottleneck and founder effect

gene flow

- movement of alleles from one population to another

- holds a species together genetically

mutations

permanent change in DNA

directional selection

disruptive selection

stabilizing selection

intrasexual

selection within the same sex (dominant male fends off weaker males and keeps females for himself)

intersexual

selection in which individuals of one sex are choosy in selecting their mates from the other sex (one sex chooses the flashiest suitor)

speciation

origin of new species

reproductive isolation

existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring.

biological

species concept that states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with other populations

morphological

species concept that defines a species by structural features

ecological

species concept that views a species in terms of its ecological niche

phylogenetic

species concept that defines a species as the smallest group of individuals that share a common ancestor

allopatric speciation

gene flow is interrupted when a population is divided into geographically isolated subpopulations

sypmatric speciation

speciation takes place in geographically overlapping populations

polyploidy

presence of extra sets of chromosomes

adaptive radiation

the rapid evolution of many diverse species from ancestral species

adaptive radiation

may follow mass extinctions, colonization of new regions, evolution of novel characteristics

spheres, rods, spirals

three most common shapes of prokaryotes

gram-positive bacteria

have simpler walls with a large amount of peptidoglycan

gram-negative bacteria

have less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides

endospores

structure that can remain viable in harsh conditions for centuries

frimbriae

hairlike appendages that help cells adhere to other cells or to a substrate

pili

allow prokaryotes to exchange DNA

taxis

the ability for prokaryotes to move toward or away from a stimulus

flagella

most common structures used for movement in prokaryotes

rapid reproduction, mutation, genetic recombination

factors that contribute to large genetic diversity of prokaryotes

genetic recombination

combining of DNA from two sources

transformation

process in which one prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment

transduction

movement of genes between bacteria by bacteriophages

conjugation

process where genetic material is transferred between prokaryotic cells

symbiosis

ecological relationship in which two species live in close contact: a larger host and a smaller symbiont

exotoxins

secreted and cause disease even if the prokaryotes that produce them are not present

endotoxins

released only when bacteria die and their cell walls break down

benefits for plants to move to land

more CO2, unfiltered sunlight, nutrient-rich soil

challenges for plants to move to land

scarcity of water, lack of structural support against gravity

gametophyte generation

haploid and produces haploid gametes by mitosis

diploid sporophyte

produces haploid spores by meiosis

rhizoids

anchor gametophytes to substrate

vascular plants

life cycles with dominant sporophyte; vascular tissues called xylem and phloem; well-developed roots and leaves; spore-bearing leaves called spophylls

common to all seed plants

reduced gametophytes, heterospory, ovules, pollen

carpels, stamens, petals, sepals

4 floral organs; all examples of modified leaves

angiosperm life cycle

gametophyte development, sperm delivery by pollen tubes, double fertilization, seed development

double fertilization

fusion of gametes that occurs after the two sperm reach the female gametophyte

double fertilization

one sperm fertilizes the egg and the other combines with the two polar nuclei, giving rise to triploid food-storing endosperm

imbibition

uptake of water due to low water potential of the dry seed

simple

fruits that develop from a single or several fused carpels

aggregate

fruits that result from a single flower with multiple separate carpels

multiple

fruits that develop from a group of flowers called an inflorescence

accessory

fruits that contain other floral parts in addition to ovaries

bryophyte

no vascular tissues, no leaves, gametophyte dominant, flagellated sperm, no seeds, no flowers, no fruit, no double fertilization

fern/fern allies

vascular tissues, leaves, sporophyte dominant, flagellated sperm, no seeds, no flowers, no fruit, no double fertilization

gymnosperms

vascular tissues, leaves, sporophyte dominant, wind-pollinated, seeds, no flowers, no fruits, no double fertilization

angiosperms

vascular tissues, leaves, sporohpyte dominant, (usually) animal-pollinated, seeds, flowers, fruits, double fertilization

anatomy

biological form of an organism

physiology

the biological functions an organism performs

regulator

uses internal control mechanisms to control internal changes in the face of external fluctuation

conformer

allows its internal condition to vary with certain external changes

negative

type of feedback that helps to return a variable to a normal range (figure 8)

positive

type of feedback that amplifies a stimulus and does not usually contribute to homeostasis in animals (one way arrow)

endotherm

generate heat by metabolism; more energetically expensive

ectotherm

gain heat from external sources

radiation, evaporation, convection, conduction

modes of heat exchange

metabolic rate

sum of all energy an animal uses in a unit of time

BMR

metabolic rate of an endotherm at rest at a "comfortable" temperature

SMR

metabolic rate of an ectotherm at rest at a specific temperature

age, sex, size, activity, temperature, and nutrition

key factors of metabolic rate

undernourishment

use up stored fat and carbs, break down its own proteins, lose muscle mass, suffer protein deficiency of the brain, die or suffer irreversible damage

filter feeders

sift small food particles from the water

substrate feeders

live in or on their food source

fluid feeders

suck nutrient-rich fluid from a living host

bulk feeders

eat relatively large pieces of food

intracellular

digestion in which food particles are engulfed by phagocytosis and liquids by pinocytosis

extracellular

digestion in which the breakdown of food particles occurs outside of cells

alimentary canal

digestive tube that extends from the mouth to the anus

circulatory fluid, set of vessels, a muscular pump

components of a circulatory system

atrium

chamber of heart that blood enters through

ventricle

chamber of heart the blood is pumped out of

single circulation

blood leaving the heart passes through two capillary beds before returning

double circulation in mammals

venae cavae

largest veins in body that empty their blood into the right atrium

countercurrent exchange

blood flows in the opposite direction to water passing over the gills; reduces heat loss

tracheal system

consists of a network of branching tubes throughout the body of an insect