Bio 221 Exam 1 Study Guide

Age of life

~3.5-3.8 billion years old

Age of earth

~4.5 billion years old

Age of animals

Animals originated in the Precambrian seas over 600 million years ago

What defines life?

chemical uniqueness, life has a hierarchical organization that does not exist in the nonliving world, reproduction, possession of genetic “program” for inheritance of traits, metabolism, development, movement, evolution, and all living organisms are made up of one or more cells

Chemical uniqueness

1. macromolecules assembled by living organisms are more complex than those of nonliving matter

2. general structure of these macromolecules is the same in all forms of life

   1. nucleic acids (DNA and RNA)

   2. carbohydrates

   3. Proteins (composed of amino acids)

   4. lipids

Life has hierarchical organization that does not exist in the nonliving world

1. atoms

2. molecules

3. cells (basic unit of life)

4. tissues

5. organs

6. organisms

7. populations

8. communities

Reproduction

living systems can reproduce themselves

Possession of genetic “program” for inheritance of traits

DNA provides the instruction on “how to build proteins”

proteins are necessary for development of unique cells with specialized functions

genetic code translate the sequence of RNA into sequence of amino acids in protein

all forms of life share the same genetic code

Metabolism

living organisms maintain themselves by acquiring nutrients from their environments

metabolism is the sun catabolic (destructive) and anabolic (constructive) rxns in body

Development

all organisms pass through a characteristic life cycle (zygote → adult)

Movement

living systems and their parts show precise and controlled movements arising from within the system

Evolution

Populations of living organisms can evolve over time (i.e., change of allele frequency between generations)

cannot evolve individually, but you can evolve as a population

What are shared traits of animals?

eukaryotes

multicellular

hetertrophs

Eukaryotes

contains membranes-enclosed nuclei and membrane-bound organelles

Multicellular

composed of many cells with specific structure and functions

Hetertrophs

not capable of manufacturing their own food

Evolution (definition)

change of allele frequencies in a population over time

Darwin’s Theory 1

Living world is always changing and changes are passed through heredity

species arise, change and many go extinct

evidence: fossil record

Darwin’s Theory 2

Common descent

all life has descended one ancestor (LUCA)

life’s history can be depicted as a branching tree: phylogeny

more closely-related species share a more recent common ancestor (→ branching) with each other

Evidence for common descent

DNA/RNA, genetic code, transcription and translation, ATP, shared genes

Darwin’s Theory 3

Multiplication of species overtime

every branching point means that one species split into 2

many species go extinct

Darwin’s Theory 4

Gradualism

phenotypically changes occur slowly and gradually eventually producing new species

in contrast: punctuated equilibrium: change happens rapidly and periods of stability can be observed between periods of sudden change

Evidence for both in fossil records

Darwin’s Theory 5

Natural selection (mechanism)

explains how organisms evolved from a common ancestor to become the great variety that can be observed today

natural selection results in traits related to increased survival and reproduction to become more common in a particular environment over time (adaptation)

at the same time, less favorable traits are being lost in the population

Results: natural selection can lead to new traits and species

Homology

similarity attributable to common origin, ie, similarities between (groups of) organisms are explained by a shared common ancestor who passed on the traits

shared traits indicate evolutionary relationship between organisms

Morphological homology

evidence of common ancestry of vertebrates

Developmental homologies

Similarities of embryo development are due to common ancestry

Sequence homology

shared sequence of nucleotides (DNA/RNA) or amino acids (protein) due to shared ancestry

Homoplasy

wings in birds, bats, and insects: used for flying but not due to a recent common ancestor

analogous structures

Natural selection two steps

1. genetic/phenotypic variations generated as the result oi mutations, genetic recombinations, gene shuffling, etc

2. sorting (i.e., selecting); survival of different traits

Microevolution

changes in allele frequencies that lead to different traits within a population over time (i.e., pesticides resistance, body size, color, etc)

Macroevolution

changes that lead to new species or taxa over time

What are the 4 evolutionary forces?

selection (natural and sexual)

genetic drift (chance event)

Gene flow (=migration of allele (individuals) out of, into, or between populations)

mutations

Hierarchical organization of animal complexity

1. protoplasmic

2. cellular

3. cell-tissue

4. tissue-organ

5. organ-system

Protoplasmic

characteristics of unicellular organisms

complete organisms that can perform all functions of life. Cell organelles are differentiated and perform specialized functions

e.g., amoeba paramecium

Cellular

Multicellular animals have cells combined into larger units

cells are not capable of independent existence cells are differentiated and have specific functions (e.g., reproduction, nutrition, etc) i.e., division of labor

Cell-tissue

aggregation of similar cells into patter of layer that performs a common function (=tissues)

e.g., cnidarians have nerve nets; gastrodermis

Tissue-organ

aggregation of tissues into larger function units, ie., organs

organs are composed of more than one kind of tissue and have more specialized functions than tissue

e.g., heart muscle tissue, connective epithelial and nerve tissue

e.g., platyhelminthes: e.g., eyes, reproductive organs

Organ-system

organs work together to perform a function, i.e., organ system

e.g., circulatory, respiratory, digestive systems

most animal phyla

Lateral

sides

spherical symmertry

any plane through center divides body into mirrored halves

radial symmetry

body can be divided into smaller halves by planes passing through the central axis

Bilateral symmetry

body can be divided into two mirrored parts (L/R) along sagittal plane

medial

midline

ventral

lower (belly) side

dorsal

upper (back) side

Anterior

toward the front

Posterior

toward the back

proximal

describes a body part that is closer to a point of attachment than another body part

distal

describes a body part that is farther away from a point of attachment than another body part

transverse plane

cross section; anterior and posterior

Frontal plane

divides in ventral and dorsal

Sagittal plane

divides in left and right

Acoelom

mesodermal cells completely fill the blastocoel. This cell-filled room; parenchyma

Pseudocoelomate

mesodermal cells lien outer edge of blastocoel; two cavities blastocoel (pseudocoel) and gut

Schizocoel

mesoderm cells fill blastocoel with band of tissue that opens up in center and then forms true coelom (surrounds blastocoel)

4 types of tissues

epithelial

connective

nervous

muscle

3 species concept

morphological (typological) species concept

Biological species concept

Genetic species concept

Morphological (typological) species concept

species are defined by morphological features

Problems: species show variation (e.g., phenotypic plasticity) and do change through time to some degree

Biological species concept

species are groups of interbreeding natural populations that are reproductively isolated from other such groups

Offspring are viable and fertile

Problems: extinct species, asexual reproduction

Genetic species concept

Geneticist’s equivalent of the morphological concept, but genetic similarity is used

problem: how much genetic difference constitutes separate species

8 taxonomic ranks and sequence

1. domain

2. kingdom

3. phylum

4. class

5. order

6. family

7. genus

8. species

Ancestral traits

characteristics that was present in common ancestor of all species in taxon

Derived traits

variants that arose later in group

Synampomorphy

derived character shared by all members of clade; evidence of homology and common descent of species in clade

Symplesiomorphy

ancestral, shared character of taxon

Monophyletic

taxon includes most recent common ancestor and all descendants of that ancestor

Paraphyletic

taxon include most recent common ancestor but not all descendants of that ancestor

Polyphyletic

you cannot trace path between all members from group without leaving the group

Endosymbiotic Theory

ancestor of eukaryotes (~2 bya): prokaryote that engulfed another prokaryote

an aerobic prokaryote: today’s chloroplast

a photosynthetic prokaryote: today’s chloroplast

both organelles have their own circular DNA

Common features of unicellular eukaryotes

no germ layers, organs, tissues

mutualistic, commensal, or parasitic (disease) relationship with other species

all requires moist environment

some with endoskeleton, some with exoskeleton, most naked

sexual and/or asexual reproduction

Types of asexual reproduction of unicellular eukaryotes

• fission: asexual multiplication

  • binary or multiple fission

  • identical cells

• Budding: unequal division

  • progeny cell smaller than parent cell and then grows to adult size

  • forms of mitosis

Types of sexual reproduction of unicellular eukaryotes

conjugation: exchange of gametic nuclei between paired organisms (e.g., paramecium)

African sleeping sickness

trypanosoma brucei

vector: tsetse fly

Malaria

• plasmodium falciparum

• vector: mosquito

• sticky blood cells block blood vessels (brain, organ)

• mosquito → plasmodium in blood stream to human liver: multiple fission (asexual)

• then to RBC: feed on hemoglobin (multiple fission)

• RBCs burst, releasing parasites and waste products

• new RBCs infected

• synchronized bouts of bursting and infecting: waves of fever and chills

• mosquitoes pick up parasites gametes from host

• sexual reproduction: fertilization in gut of mosquito

• zygote develops into sporozoite that is transferred to human host

Amoebozoa

• Naegleria fowleri

• warm water (e.g., ponds, lakesm untreated swimming pools)

• usually eats bacteria

• enter through nose: water sports

• through olfactory nerve to brain

• rare infection, usually fatal (~5 days)

• symptoms: headache, fever, stiff neck, vomiting, seizures, coma

Evolution of multicellular

singular cells that can do everything

aggregation of undifferentiated cells (e.g., some algae)

cells with different functions and only particular cell types can reproduce (true metazoa)

Who is the sister group of all animals?

choanoflagellates

Choanocytes

generate water stream (move food, waste products oxygen)

Atchaeocytes

ameboid cells that move in mesohyl

can differentiate into other cell: totipotent

Spongocytes

secrete spongin (structural protein in mesohyl)

Sclerocytes

secrete spicules (provide stiffness)

Pinacocytes

flat, thin cells

Types of asexual reproduction of multicellular

Budding: external buds can detach, float away, form new sponges

fragmentation: pieces of sponge detach, float away, adn rebuild sponge (somatic embryogenesis)

Types of sexual reproduction of multicellular

most sponges with sexual reproduction are monoecious

one sponge releases sperm → taken up by another sponge → fertilize egg

zygote → free swimming parenchymula larva → settles somewhere else, adn develops into sponge

What does monecious mean?

Mesohyl

Cells are loosely arranged in gelatinous matrix

Spongin

Spicules

General features of sponges

Important phyla with one example

Movement: whoe does what?, general structure of cilia and flagella, sliding microtubule