Biology 112-Exam 1

Natural selection, Animal diversity and Body plans, Neuron and Action potential, Nervous system, Muscles

Artificial Selection

The selecting and breeding of individuals with desired traits.

Homology

A similarity resulting from a common ancestor.

Comparative embryology

It reveals anatomical homologies not visible in adult organisms.

Vestigial Structures

Remnants of features that served a function in the organism’s ancestors.

Convergent Evolution

The evolution of similar, or analogous, features in distantly related groups.

What did the study of fossils do to help lay the groundwork for Darwin’s ideas?

Fossils are able to show the important transitions from land to sea ancestors and how animals and organisms have evolved overtime.

How did Lamarck’s Hypothesis of Evolution compare to Darwin’s ideas about Natural Selection?

Lamarck hypothesized that species evolve through use and disuse of body parts and the inheritance of acquired characteristics. This led to Darwin’s idea that a change within the individual that leads to acquired characteristics lead to certain animals surviving.

Describe the important ideas from Darwin’s *The Origin of Species*.

Descent with modification: The unity of life with common ancestor, the diversity of life, and the ways organisms are suited to life in their environments.

What observation of natural phenomenon were important in shaping Darwin’s ideas about Natural Selection?

A visit to the Galapagos Islands in 1835 helped Darwin formulate his ideas on natural selection. He found several species of finch adapted to different environmental niches. The finches also differed in beak shape, food source, and how food was captured.

Key Feature of Natural Selection

Individuals with certain heritable traits survive and reproduce at a higher rate than other individuals.

\n Key Feature of Natural Selection

Natural selection increases the frequency of adaptations that are favorable in a given environment.

\n Key Feature of Natural Selection

If an environment changes over time, natural selection may result in adaptation to these new conditions and may give rise to new species.

\n Key Feature of Natural Selection

Note that individuals do not evolve; populations evolve over time.

\n Key Feature of Natural Selection

Adaptations vary with different environments.

What evidence supports the theory of evolution?

Biogeography is the scientific study of the geographic distribution of species, which provides evidence of evolution. When there are similarities in species that have been found in different places.

Explain natural selection in relation to antibiotic resistance in bacteria.

When bacteria cause an infection and the individual is treated with antibiotics, any bacteria that have the antibiotic-resistance trait will survive while all others will die off. The proliferation of antibiotic-resistant bacteria is a major medical problem.

Explain natural selection in relation to the soapberry bug.

With the soapberry bug it originally would eat the green balloon vine fruit that was native and large, and then the golden rain tree was introduced as a smaller fruit. The soapberry bug got longer antenna’s and was easier to eat the golden fruit. Overall, the soapberry bug will still eat both fruits. The beak length of the soapberry bug was longer when eating the native fruit, where the introduction of the golden rain tree fruit had them only need shorter beak lengths.

Speciation

The process by which one species splits into two or more species.

Microevolution

Consists of changes in allele frequency in a population over time.

Macroevolution

Refers to broad patterns of evolutionary change above the species level.

Morphological Species Concept

Defines a species by structural features, it applies to sexual and asexual species but relies on subjective criteria.

Allopatric Speciation

A population is divided into geographically isolated populations. A geographical barrier is dividing the two populations.

Sympatric Speciation

Occurs in populations that live in the same geographic area; occurs if gene flow is reduced. The 3 different ways of reduced gene flow is polyploidy, sexual selection, and habitat differentiation.

3 different ways of reduced gene flow

Polyploidy, sexual selection, habitat differentiation.

Polyploidy

The presence of extra sets of chromosomes due to accidents during cell division.

Autopolyploid

With one species individual and occurs more with plants. The cell division error that occurs is they double the number of chromosomes than original.

Allopolyploid

Happens between two different individuals and occurs more with animals. The mitotic/meiotic error in a hybrid cell that occurs is the chromosomes are doubled.

Punctuated Equilibrium

Is the hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change.

Phyletic Gradualism

A model of evolution which theorizes that most speciation is slow, uniform, and gradual.

Prezygotic barriers

Pre=before zygotic=zygote

Prezygotic barriers: Habitat isolation

Found in a specific habitat/ isolation.

Prezygotic barriers: Temporal isolation

Breeding at a specific time of the year \*time influences how they interact.

Prezygotic barriers: Behavioral isolation

How they interact with one another.

Prezygotic barriers: Mechanical isolation

The spirals the shell must be going in the same direction.

Prezygotic barriers: Gametic isolation

Gametes don’t interact successfully.

Postzygotic barriers

Post=after zygotic=zygote

Postzygotic barriers: Reduced hybrid viability

Can’t survive in environment or have difficulty surviving.

Postzygotic barriers: Reduced hybrid fertility

No successful mating.

Postzygotic barriers: Hybrid breakdown

Offspring don’t survive.

What is the Biological Species Concept?

The biological species concept is 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 members of other such groups.

What are the limitations to the biological species concept?

Its limitations is that it cannot be applied to fossils or asexual organisms (including all prokaryotes). Emphasizes absence of gene flow.

Describe the mosquitofish evolution experiment.

With the mosquitofish evolution experiment they looked at the differences in escape acceleration and survival and the differences in body shape.

With predators the body shape that enables rapid bursts of speed.

Without predators the body shape that favors long, steady swimming.

The escape acceleration was faster for the fish that were a part of the pond where predators were present.

The survival rate with predators was higher for the fish that were a part of the pond where predators were present.

Describe the sexual selection in cichlids experiment.

Experiment: Researchers placed male and female fish together in 2 aquaria tanks.  One with normal light, the other with an orange light.  Researchers observed mate choices.

Normal light: females preferred males of their own species.

Orange light: females responded indiscriminately.

Describe how habitat differentiation can result in speciation.

Sympatric speciation can result from the appearance of new ecological niches.

Explain how hybrid zones form

Step 1: There will be a barrier to gene flow and that population now no longer shares its genes with other species.

Step 2: The isolated population diverges and there are now two species.

Step 3: The hybrid zone is now formed and contains individuals of both species that came into contact with one another and formed hybrid individuals.

What is a hybrid region

A hybrid is a region in which members of different species mate and produce hybrids.

A change in environmental conditions can result in the relocation of existing hybrid zones.

What are the three possible outcomes for hybrids over time?

Reinforcement: reinforcing 2 distinct species which could decrease the amount of hybrid individuals

Fusion: fusion of species, resulting in either offspring, 2 fuse into 1,

Stability: have 2 species and the hybrid population will be maintained as well

Provide two examples of how scientists studied the genetics of speciation.

In Japanese Euhadra snails, the direction of shell spiral is controlled by a single gene. Mating is prevented between snails of different chirality by genital mismatch.

In monkey flowers (Mimulus), at least two loci affect flower color, which influences pollinator preference.

Heterotroph

An organism that eats other plants or animals for energy and nutrients.

Hox genes

Master of regulatory genes that control embryonic development. They are unique to animals, they play a role in how an organisms develops depending on how they are expressed, they play a role in the Cambrian explosion.

Monophyletic

One group of organisms that descend from a single organism.

Phylogenetic tree

A diagram composed of unrelated organisms’ descendant from more than one ancestor.

Cephalization

The process that places the mouth closer to the brain and sensory organs that help the organisms search for food sources more quickly.

Acoelomate

Has no body cavity.

Pseudocoelomate

Has a space, aka fake body cavity.

Coelomate

Has a true body cavity.

Cambrian explosion-Geological time scale

1\.Ecological Causes-Predator/Prey Relationship

2\.Geological Causes-Increased rates of oxygen provided a more favorable environment for eukaryotes

3\.Genetic causes-Hox genes-what different features an animal will have and how it is specific to them

Craniate

Anything that has a bony skull.

Gnathostomes

Vertebrates that have jaws.

Vertebrate

Organisms that have:

2 or more sets of Hox genes

More complex nervous system

Vertebrae backbone

Neural crest

Swim bladder

Characteristic that:

maintains buoyancy

makes it easier to live in water

filled with gas

Tetrapods

Organisms that have:

Limbs

4 legs

Neck

No gill slits

Amniotic

Tetrapod’s that have a terrestrially adapted egg.

They can have internal fertilization with egg with shell, they don’t rely on water to reproduce

Amniotic egg

Mammals, birds, reptiles, anything that produces egg.

Ectothermic

Dependent on external sources of body heat

What traits distinguish animals from other Kingdoms?

Animals are multicellular, heterotrophic eukaryotes with tissues that develop embryonic layers. They lack cell walls, have nervous and muscle tissues, and the cells are held together by collagen and specialized junctions.

Describe the closest living relative of animals.

Choanoflagellates- the flagellated protist.

Asymmetry

No symmetry

Radial

Symmetrical from top and bottom views

Bilateral

one distinct split in half: anterior/posterior, dorsal/ventral

Embryological development-Symmetry and Germ layers: Radiate-diploblasts

Two germ layers-ectoderm and endoderm

Cnidarians, ctenophores

Embryological development-Symmetry and Germ layers: Bilatera-triploblasts

Three germ layers- ectoderm, mesoderm, endoderm

All other animals

Tissues: Embryological development

Parazoa: no true tissues, ex: sponges

Eumetazoa: majority of animal

Tissues: Triploblastic organisms

Ectoderm-skin and nervous system

Endoderm-lining of the gut trachea and lungs

Mesoderm-muscles, skeleton, circulatory, kidney

Protostomes

Cleavage: spiral and determinant

Coelom Formation: Mesoderm splits-Schizocoelous

Fate of Blastopore: Mouth

Deuterostomes

Cleavage: radial and indeterminate (stem cells)

Coelom Formation: Archenteron folds-Enterocoelous

Fate of Blastopore: Anus

Porifera

Sponges

Aquatic/marine

Parazoans-no true tissues

Asymmetrical

Adults are sessile-less mobile- they are settled on a substrate and grow

Larvae have more motility.

Cnidaria

Corals

Jellyfish

Sea anemone

Metazoans

Diploblastic- endoderm and ectoderm

Radial symmetry

Contain cnidocytes that contain menatocysts

Platyhelminthes

Flatworms

Bilateral symmetry

Development of cephalization

Planaria

Flukes

tapeworms

Mollusca

Protostome

Mantle(secrets shell), muscular foot, visceral mass

Chiton

Clams, muscles, scallops

Snails

Slugs

Cephalopods: Octopus, squid, nautilus

Arthropoda

o   Protostome

o   Segmentation

o   Exoskeleton

§  Chitin

§  Cuticle

§  Molting

o   Jointed appendages

o   Respiratory

§  Gills (aquatic)

§  Trachea (terrestrial)

o   Open circulatory system

§  Hemolymph

Arthropoda: Subphylum-Hexapoda

o   Species

§  Insects

§  Springtails

o   Body

§  Head, thorax, abdomen

§  Antennae

§  3 pairs of legs

o   Mostly terrestrial

Arthropoda: Subphylum: Myriapoda

o   Species

§  Millipedes- herbivorous, 2 legs/segments

§  Centipedes- carnivorous, 1 leg/segment.

o   Body

§  Many segments

Arthropoda: Subphylum: Crustacea

o   Species

§  Crabs

§  Lobsters

§  Crayfish

§  Shrimp

o   2 or 3 body parts

§  Antennae

§  3 or more pairs of legs

o   Mostly Marine and Freshwater

Arthropoda: Subphylum: Cheliceriformes

o   Species

§  Horseshoe crabs

§  Spiders

§  Scorpions

§  Ticks

§  Mites

o   Body

§  1 or 2 parts

o   Named for chelicerae

Annelida

o   “Little rings”

o   Protostome

o   Segmented worms

o   Oligochaeta

o   Hirundinea

o   Polychaeta

o   Complete digestive system

o  Closed circulatory system

Nematoda

o   Round worms

o   Protostome

o   Pseudocoelomates

o   Many parasitic

o   heartworms

Echinodermata

o   Deuterostome

o   Water vascular system with tube feet

§  Used for motion, feeding, respiration.

o   Secondary radial anatomy

§  Larvae bilateral

o   Capable of regeneration

o   Brittle star

o   Sea star

o   Sea urchin

o   Sea cucumber

Chordata

o   Deuterostomes with 4 key traits

§  Notochord

§  Dorsal, hollow nerve cord

§  Pharyngeal slits or clefts

§  Muscular, post-anal tail

Subphylum’s of Chordata: Cephalochordata: Lancelets

o   Small filter feeders

o   Bury in substrate

Subphylum’s of Chordata: Urochordata: Tunicates

o   Larvae is motile

o   Adults are sessile on the ocean floor

o   Filter feeders

Subphylum’s of Chordata: Hagfish

o   Craniates: chordates that have a head

o   Cartilage skull

o   Only rudimentary vertebrae; retain notochord

o   Lack jaws

Subphylum’s of Chordata: Lampreys

o   Larva; looks like lancelet

o   Skeleton-cartilage without collagen

o   Sheath around notochord

Subphylum’s of Chordata: Chondrichthyes

o   Skeleton (derived)

§  Predominately cartilage

o   Evolution of teeth

o   Species

§  Sharks

§  Rays

§  Skates

Subphylum’s of Chordata: Ray-finned fish

o   Familiar fish

o   Tuna

o   Clownfish

o   Seahorse

o   Eel

o   Fins

§  Bony rays are inside fins

o   Swim bladder

§  Used for buoyancy control

§  Aids in fish staying at a certain depth level

Subphylum’s of Chordata: Lobe-finned fish

o   Rod shaped bones

§  Allows for support-land

o   Order- coelacanths

o   Order- lungfish

Subphylum’s of Chordata: Amphibians

o   Species

§  Frogs & Toads

§  Salamanders & newts

§  Caecilians

o   “Both ways of life”

§  Larval: swim

§  Adults: more terrestrial

o   Moist skin-gas exchange

o   Fertilization- external

o   Egg- no shell!

o   Need water for reproduction

Subphylum’s of Chordata: Reptiles

o    

§  Lizards

§  Snakes

§  Turtles

§  Crocodilian

o   Scales

o   Internal fertilization

o   Ectothermic

o   Species

§  Birds(Aves-class)

o   Flight

§  Feathers: for thermal regulation and flight

§  No urinary bladder

§  One ovary

§  Hollow bones

§  Toothless

§  Mammalia

o   Endothermic

§  Maintain a constant body temperature

§  Allows for them to be mobile at any time

§  Beneficial for how they respond to their environment

§  Requires them to obtain a lot of food

Mammals have:

o   Mammary glands

o   Hair

§  Endothermic: temperature regulation

o   Kidney: execratory system

Mammals: Monotremata

o   Lay external eggs

o   No nipples

o   Species

§  Platypuses

§  echidna

Mammals: Marsupialia

o   Embryo continues development in a pouch

o   Species

§  Kangaroos

§  Opossums

§  Koalas