Bio 205 Midterm One

Endo vs Ecto parasites

1) Endoparasite - lives inside their host Examples of degenerate evolution because they loose the complex traits of free-living organisms. They can rely on diffusion of nutrients already digested by their host and devote the majority of their energy to reproduction, which improves their fitness. 2) Ectoparasite - lives outside of their host

Diploid

2N - there is two sets of identical chromosomes

Microevolution

A change in a single gene (allele frequency) from one generation to the next within a population. Microevolution is the minimal level of evolution that can occur.

Meristems

Land plants only grow at their meristems. There are two types of growth by meristems Apical - at apex, meaning the roots and shoots of the plant Lateral - Increase in thickness

Class Tubellaria (free-living)

Not parasitic Majority are predators, some scavengers Simple organs and simple brain Brain - cluster of neurons in the head region that control other parts of the body

Adaptive Radiation

Rapid evolutionary change that results in an explosion of diversity at high taxonomic levels. An example of adaptive radiation is the cambrian explosion of life, when almost all groups of animals first appeared.

What groups are found in Clade Archaeplastida?

Red algae: Produces Very abundant in marine habitats, especially in intertidal areas Green algae: Extremely important producers Land plants evolved from green algae

Fossil

Remains of an organism on earth that has persisted for hundreds of millions of years.

Retention of the embryo by parent plant

Retention of the embryo (multicellular developing diploid organism) by parent plant protects from desiccation

Bryophytes

Superphylum

Early Gnathostomes

The first successful Gnathostome was the Placoderm, which were dominant 450-350 million years ago. The Placoderm was a highly cephlalized and motile predator with advanced camerca-like eyes and other sensory capabilities They also had advanced fin development that allowed them to maintain stability and movement control, particularly preventing from yawing, pitching, and rolling so that they could stay parallel with the direction of movement.

Taxon

The general term for the group to which an organism is assigned.

The "proto-jaw"

The proto-jaw was the intermediate evolution of the jaw, which evolved from the phrangial gill slits and the structure around them. The proto-jaw enabled the organism to slightly open its mouth, increasing the volume of the pharynx and creating suction. This was beneficial for the organism because the suction increased respiration through the gills. The jaw evolved because even at a rudimentary stage, it was beneficial for the organism.

P. Echinodermata Traits

Water Vascular System: Water travels through madrepoite and passes through a series of tubes inside the organism. It is a hydraulic system, meaning the water creates pressure that allows the tube feet to move for locomotion. Many are predators: Tube feet are used to pry apart the mussels shell so that stomach can be everted, or shot outside the mouth, into the shell and secrete digestive enzymes to consume the mussel

Ancestral vs Derived traits

1) Ancestral Traits - traits shared by all members of a group because of shared ancestry. Possessed by both the ingroup and the outgroup. Not useful because they cannot be used to differentiate the members of the ingroup from each other. 2) Derived Traits - recently evolved traits. Possessed by the ingroup but not the outgroup.

P. Nemoatoda Importance to humans

1) Cause medicinal problems for humans since one courter of all humans have nemetodes 2) C. elegans is a model species on which medial research has been done, particularly mapping the first genome, research on human development, and the human nervous system

P. Porifera Importance to humans

1) Chemicals isolated from sponges are useful as antibiotics 2) Cancer-fighting agents isolated from sponges 3) Sponge reefs have some ecological importance because they are habitats for other marine animals on which we depend

What are the traits of the plants?

1) Cuticle 2) Stomata 3) Spores 4) Retention of the embryo by parent plant 5) High concentration of cellulose in the cell walls 6) Photosynthetic 7) Meristems 8) Alternation of generations

P. Platyhelminthes importance to humans

1) Enoparasitic flatworms pose a non-trivial medical problem for humans 2) Free-living flatworms have important role in the food web

Traits of the group (including those that guarantee some dependency on water)

1) Have vascular tissue with lignin - provides rigidity and is Hydroscopic, so it resists water 2) Sporophyte dominant - Gametophyte stage is very short 3) Swimming sperm - that guarantees some dependency on water, especially during reproduction. The sperm are prone to desiccation, because without water they will dry out and not survive. 4) Lack seeds

P. Cnidaria Importance to humans

1) Important constituents in coral reef habitats, which provide habitats for many organisms on which we depend 2) Huge biomass of cnidarians in oceans, therefore they serve as an important food source for organisms on which we depend

Problems with the Biological Species Concept

1) It excludes asexual species 2) Logistically, it is difficult to apply in practice since organisms from different populations often do not want to breed with each other in captivity.

Traits of Bryophytes

1) Lack vascular tissue 2) Lack a cuticle 3) Lack stomata 4) Seeds, leaves, and roots 5) Have swimming sperm 6) Gametophyte dominant

P. Annelida Importance to humans

1) Leeches have medicinal purpose since they are used to reduce excess fluid that builds up after surgery, which decreases a patient's recovery time 2) Class Oligochaete and Class Polychaeta have some ecological importance in the food web

C. Cephalopoda Importance to humans

1) Present and relatively abundant in all major habitats, therefore ecologically important in food web 2) Food source for humans

Examples of paraphyletic groups

1) Reptiles leave out birds 2) Green algae leaves out land plants 3) Kingdom Protista leaves out Kingdoms Animalia, Plantae, and Fungi

Why taxonomy is useful

1) Taxonomy is useful for testing drugs, and other treatments and research purposes, because they can be tested on animals that are evolutionarily related to us to know their effect on humans. 2) Taxonomy is useful for knowing how to deal with pathogens that are harmful to humans. A drug or treatment that harms one pathogen may also affect a pathogen evolutionarily related to it.

Examples of Convergence

1) The development of fusiform shape in many aquatic organisms is not due common evolutionary decent but because fusiform shape is an adaptive trait that allows organisms to move through water effectively. 2) The development of advanced sensory systems, specifically large brains and advanced camera-like eyes, in both cephalopods and vertebrates is not due to common evolutionary decent. They are adaptations that allow these organisms to hunt, track, catch their prey as advanced predators.

Seedless Vascular plants

12,000 spp (most are ferns)

Haploid

1N - there is one set of chromosomes (gamete)

What trait of vascular plants evolved convergently in certain bryophytes? (what group of bryophytes?).

A few mosses have evolved vascular tissue, however it is not homologous with the vascular tissue of vascular plants. We know this because the vascular tissue in some mosses does not contain lignin, a chemical that provides rigidity and retains water, that is in the vascular tissue of other plants.

Teleology

A goal-oriented process. Evolution is not goal oriented. It is based off of fitness, an organisms ability to survive and reproduce. Organisms develop adaptations, evolved traits that help them cope with an ecological problem, because of opportunities for survival.

Neutral Mutations

A neutral mutation is when there is a nitrogenous base change that causes a codon to code for a different amino acid, but the protein function stays the same. A mutation that does not affect the organism's fitness.

Silent Mutations

A silent mutation is where there is a nitrogenous base change in a DNA sequence, but the codon with the change still codes for the amino acid due to redundancy in the genetic code. A mutation that does not affect the organism's fitness.

Biological Species Concept

A species is set of individuals who can reproduce with each other and produce fertile offspring Species is the only taxonomic level that has an objective definition, meaning it is universal.

Genetic Drift

A sudden change in the genetic make up of a population due the random wiping out of members in the population.

C. Cephalopoda

Advanced Predators: Advanced motility - foot evolved into arms, tentacles, siphon, which is used it for jet propulsion Camera-like eyes that have the capacity to focus light and detect movement Tentacles used to capture prey Radula evolved into beak that crushes and kills prey Have relatively complex brain to anticipate their prey's movements

Class Agnatha

Agnathans are jawless vertebrates and class Agnatha are the extant Agnathans. Two examples of extant agnathans are the hagfish, a scavenger that feeds on decaying matter, and the Lamprey, which is an ectoparsite latches onto fish and uses tough, rasping mouth to make a wound on its host and an anticoagulant enables it to feed on the blood of its host.

Kingdom Animalia

All appeared during Cambrian Explosion 550 mya Key Traits of Animals: 1) Multicellular 2) Tend to be motile 3) Heterotrophic 4) Lack cell walls 5) All animals have Blastula stage in development, all except sponges have gastrula stage Derived for Kingdom Animalia, but ancestral for all groups within the kingdom.

SP. Myriapoda

All terrestrial Have antennae Many trunk segments covered by cuticle Different foraging modes: Millipedes are herbivores, they eat plant matter and decaying material Centipedes are predators and attack living organisms Importance to humans: Help control number of other arthropods that are problematic for humans

C. Polychaeta ("many setae")

Almost all are marine Some are motile predators, others are sessile tube dwellers called "feather dusters" with arms covered in cilia for feeding

SP. Chelicerata

Almost exclusively terrestrial Have Chelicerae, which are fangs that are often venomous Lack antennae Ecologically because they are important constituents in terrestrial habitats Substantial importance to humans 1) Consume other arthropods that are problematic for humans 2) Some are vectors of disease, specifically ticks and mites carry disease from one host to another

Camera-like eye

Another complex structure that was beneficial as it evolved was the camera-like eye, because it gave the organism increasing knowledge about the surrounding environment in every stage of development, which was very adaptive.

How can Clade Archaeplastida be a clade, if it includes some protists?

Archaeplastida is a clade because it does not matter what groups a clade contains, as long as it is monophyletic, meaning it contains an ancestor and all of its descendants. That is, the fact that Kingdom Protista is a mess does not mean that any group containing a protist cannot be a clade. Archaeplastida is a true clade because it consists of red algae, green algae, and land plants, which together are a monophyletic group.

Isotopes

Atoms of the same element that have different masses due to a different number of neutrons

Ecological importance of Bryophytes

Bryophytes are ecologically important because mosses create bog habitats, particularly mosses in the genus Sphagnum. Bog habitats of Sphagnum have great ecological importance because they cover 3% of the earth's terrestrial surface and hold 30% of the organic carbon in living system, making them important carbon sinks.

Lack cuticle

Bryophytes lack a cuticle, an outer, non-mineral covering that is excreted by epidermis cells and that is hydrophobic (repels water). Without a cuticle, Bryophytes cannot prevent desiccation and water quickly leaves their cells. Since they lack this trait, they are restricted to live in moist, temperate environments where they are not prone to desiccation.

Lack vascular tissue

Bryophytes lack vascular tissue, tubes that allow water and nutrients to be distributed throughout larger plants. Without vascular tissue, bryophytes are very thin and small because they have to rely on diffusion to get nutrients. Since they are dependent on diffusion, bryophytes are restricted to living in moist, temperate environments.

P. Mollusks Classes

C. polyplacophora, C. Gastropoda, C. Cephalopoda, C. Bivalvia

How cladistics works

Cadists first chose an ingroup (the focal group). Then they compare the ingroup to the outgroup (the group just outside the ingroup) to determine the derived traits (recently evolved traits) of the ingroup. Then they compare the members of the ingroup to each other to determine how they diverged from each other to construct their evolutionary history.

Phenetics

Categorizes organisms based on the overall similarity of all of their traits. Phenetics is flawed system because it does not take into account evolutionary history. For example, birds evolved from a group of reptiles, but they were categorized as a separate group based on phenetics.

P. Porifera Cell Types

Cell Types: 1) Choanocytes - line inside of sponge waving flagella to take in food particles and pass on to amoebocytes 2) Amoebocytes - Motile cells that take food from Choanocytes and distribute it to other cells 3) Porocytes - form in circles to create pores that bring water into the body of the sponge Intercellular digestion - digestion occurs within individual cells

Mutations

Changes in genes that cause changes in function

Charophytes and their importance to plant evolution

Charophytes is the group of green algae that is the sister group to land plants....

Gnathostomes

Clade of vertebrates with a jaw The jaw is a derived trait of vertebrates that greatly improves the taxon's evolutionary fitness because it enables multiple was of foraging Gnathostomes first evolved about 470 mya based off of their good fossil record, however, we do not have record of their precise evolution, so this is not the exact date they first appeared.

How clades fit into phenetic taxa or vice-versa

Clades can fall anywhere in the taxonomic hierarchy. For example, Kingdom Animalia is clade at a very high taxonomic level and Ecdyozoa is also a clade at the superphylum level.

Modern-day Gnathostomes

Class Chondrichthyes (cartilaginous fishes) Cartilaginous skeleton - skeleton made of cartilage Strong jaws Fusiform shape Well-developed fins Highly cephalized No means of regulating buoyancy, which means they have to spend energy swimming upwards. They only have large livers for bouyancy.

Cladistics

Classifies organisms based on evolutionary history

Animal Development and how it is conservative

Conservative traits are ones that remain constant over large periods of evolutionary time. Development is a conservative trait because a unique derived trait of all animals is the blastula stage in development. Animals can be categorized based on their development, since all animals develop the same way.

SP. Urochordata (tunicates)

Covered by outer protective coat (tunic) Differences in larval and adult stages: As adults sessile, bag-like filter feeding organisms that extract food from the water with pharyngeal gill slits and have lost the three other chordate traits In the larval stage, they are motile and posses all four chordate traits.

Why is Kingdom Protista important ecologically?

Critical constituents of the food web as autotrophs. They are primary produces that are the foundation of the food web.

Clade Bilateria (superphylum)

Defined by bilateral symmetry

P. Cnidaria derived traits

Diploblastic - do not have a mesoderm Cnidocyte - a specialized cell containing an organelle called a nematocyst that poisons and immobilizes large prey so they can use their tentacles to draw it into their mouths.

Clade Lophatrophazoa

Do not molt Have lophatrore larval stage or trophaphore feeding structure, which is a ciliated feeding structure

P. Chordata traits

Dorsal nerve cord - nerves passing through the back region Pharyngeal gill slits -a series of openings in the throat region Postanal tail Notochord - provides rigidity

P. Echinodermata Ecological Importance

Ecological importance as constituents in the food web that supports animals on which we depend.

P. Nemoatoda Traits

Endoparasites or free-living Very small or microscopic Has cuticle Has hydrostatic skeleton Has complex organs because cannot rely on diffusion of oxygen and nutrients with cuticle and hydrostatic skeleton Only has longitudinal muscles, results in thrashing movement

P. Echinodermata Evolutionary importance

Even though they have radial symmetry as adults, fall into clade bilateria because have bilateral symmetry as larvae.

Macroevolution

Evolution that is the accumulation of microevolution over millions of years.

Phylogeny

Evolutionary history

Evolution of the group

First appeared 430 - 405 mya We know when seedless vascular plants first appeared because of a well preserved early fossil of the plant, Agaophyton. We know that Agaophyton was a vascular plant it was large and showed branching

When did group appear and what form do fossils take?

First appeared 470 mya, however they do not fossilize well because they do not have lignin, a chemical that provides rigidity.

Molecular Clock

For molecular clock, biologist compare the orthologous gene, a gene that has the same function but has the accumulation of mutations, in two extant organisms to determine how many mutations have occurred in the gene since the organisms diverged. Then, biologists calibrate the clock, meaning they use the absolute date the species diverged, which was determined by radiometric dating, to find the rate that mutations occur in the orthologous gene. The rate of mutations can be used to determine the divergent state of two other extant organisms that have the same orthologous gene but have poor fossil records.

Where do charophytes live?

Freshwater habitats

Cuticle

Generalized term for an outer non-mineral covering that is secreted by the epidermis Hydroscopic, meaning repels water (preventing desiccation) and gives rigidity for structural support Analogous, but not homologous with the cuticle of Echdyozoa

What is wrong with green algae taxonomically?

Green algae is the ancestor of land plants but the group excludes land plants, making it paraphyletic.

Alternation of generations

Haploid and diploid stages that are both multicellular

Spores

Haploid cells (one copy of allies for every gene) that have some level of protection ( against desiccation) so they can be released into the environment and survive from some period of time

Other traits of mollusks

Have Coelom: Coelom - body cavity lined with mesodermily derived tissue. The coelom is filled with fluid pressing against the body cavity and works as a hydrostatic skeleton that provides rigidity and allows bodily functions, particularly locomotion. Hydrostatic skeleton is particularly important for organisms without a shell, such as slugs.

P. Nemoatoda ecological importance

Important constituents in terrestrial habitats

Importance of radiometric dating in molecular clock

In molecular clock, radiometric dating is used to calibrate the clock. For molecular clock, biologists compare the orthologous gene of two extant species to determine the number of mutations that have occurred between the species. This is only a relative measurement. Without the absolute date, the species diverged the rate that mutations occur in the orthologous gene cannot be determined.

How does alternation of generations differ from what we see in humans and most animals?

In order for an organism to have alternation of generations they need to have multicellular haploid and diploid forms. Humans and most animals do not have alternation of generations because our haploid stage is single-cellular as sperm and egg and not multicellular

Evolution of complex structures

In order from a structure to evolve, especially a complex structure, it had to be beneficial to the organism while it evolved. Complex structures also have to evolve from structures that are already present.

"Hybrid" system

In the past, scientist classified organisms based phenetics, or the overall similarity of all traits. More recently, scientists use cladistics, which categorizes organisms based on evolutionary decent. Today, our classifications for organisms are a mixture of phenetics and cladistic classifications. Even though they are not evolutionarily correct, scientists hold onto many phenetics classifications. Cladistic classifications are used to clarify the evolutionary decent of groups of organisms. For example, a mollusc is in both phylum mollusca and clade Ecdyozoa.

Cartilaginous skeleton

It was hypothesized that the bone skeleton evolved from the cartilaginous skeleton of the cartilaginous fishes This is false because fossil discovered of organism with bone skeleton that dates back to before cartilaginous fishes first appeared. This means that Cartilaginous fishes are an evolutionary shoot off from an ancestor with a bone skeleton making the cartilaginous skeleton is a derived trait of cartilaginous fishes.

P. Arthropoda Traits

Jointed legs - appendages that have more than one segment, that are connected by muscle tissue and allow for mobility Cuticle - hard exoskeleton that protects from desiccation and predators Lack cilia

Linaeus Hiearchy

Linnaeus grouped species into a hierarchy of increasingly inclusive categories: Domain, Kingdom, Phylum, Class, Order, Family, Genius, Species The levels of the hierarchy convey the degree of similarity between organisms. For example, organisms in the same phylum could be significantly different from each other but organisms in the same species are very similar to each other.

SP. Trilobita

Long extinct (about 250 million years ago). 500 million years ago they were very diverse and abundant Great fossil record because they were relatively large and had a hard exoskeleton Marine organisms that were well preserved in marine sediment No importance to humans

C. Oligochaete ("few setae")

Mainly terrestrial, some freshwater Mainly scavengers Posses coelom that serves as hydrostatic skeleton provides rigidity for longitudinal and circular muscles to contract on How earthworms move: Bristles are pushed outward to anchor rear of earthworm in soil and contract circular muscles, pushing the head forward , then they anchor their head and contract the longitudinal muscles to pull up their rear end.

C. Polyplacophora (chiton

Marine, mostly in inner-tidal Most similar to ancestor Motile Flat, shell with eight segments Grazers that use radula to scrape algae off if rocks Use foot to hold on to rock, move slowly

Population

Members of the same species that live in the same geographical area. The significance of a population is that it determines which individuals in the same species can interact with each other.

Stomata

Microscopic pores in leaves that can be opened to let CO2 and water in and closed again to prevent from desiccation

Types of Clades

Monophyletic - a true clade, a taxon that includes an evolutionary ancestor and all of its descendants. Polyphyletic - a taxon that includes organisms from multiple evolutionary lineages. Paraphyletic - a taxon that leaves out part of an evolutionary lineage.

C. Bivalvia

Most are sessile Lack a radula (only class that doesn't have it) Filter feeders - use siphon, a form of the foot, to bring water in and squirt it out Shell has two halves hinged on a strong abductor muscle

Elytra of beetles

Most successful groups of insects is beetles. Their success is due to their elytra, which are unique to beetles. They are forewings that protect the light and fragile flying wings as a hard exoskeleton. The elytra allow for beetles to have more versatility in terms of habitat Particularly, they are able to burrow, whereas other insects cannot without damaging their wings.

C. Hirudinea

Mostly freshwater Ectoparasites Mouth contains mineralized teeth that cut into flesh of host Use anticoagulant to keeps blood from clotting so they can feed on the blood of their host They lack setae Highly motile, using their longitudinal muscles to swim

Process in which evolution occur

Natural Selection, genetic drift, and mutations.

What are the problems faced by an organism that "invades the land"?

Needs means to avoid desiccation Structural support Physical protection Protection from predators Way of getting/generating food

P. Porifera Traits

No symmetry Lack gastrula stage in development No true tissue: tissue - cluster of cells that carry out a coordinated function No organs: Organ - structure consisting of two or more tissue types that carries out a specific bodily function Sessile - remain attached to a substrate Derived Traits: 1) Spongin - protein that give the sponge elasticity and some rigidity 2) Spicules - mineral structures that give the sponge rigidity so that it can support itself

Class Trematoda (flukes)

Non-free living live in tissues of hosts in larval stages and mature into adulthood in human gut Rely on diffusion to get oxygen and nutrients and all of their energy to reproduction Complex life cycle in which they live in different hosts

Cuticle

Non-living structure secreted by the epidermal cells that provides rigidity Prevents desiccation

P. Cnidaria

Not a clade 10,000 spp Almost exclusively marine

P. Chordata

Not a clade 105,000 spp, highly successful Abundant and diverse in all major habitats. They are the most dominant organisms in all major habitats and have been for the last 300 million years.

P. Nemoatoda (roundworms)

Not a clade 12,000 species, not successful but very abundant All major habitats (especially terrestrial in soil)

P. Platyhelminthes (flatworms)

Not a clade 12,000 spp, moderately successful Mostly aquatic, some terrestrial

P. Annelida (segmented worms)

Not a clade 12,000 spp, not very successful Found in all major habitats

P. Hrmicordata (acornworms)

Not a clade 300 spp, not successful at all Exclusively marine

P. Porifera

Not a clade 5,000 spp, not very successful Almost exclusively marine Decent fossil record due to spicules and spongin

P. Echinodermata

Not a clade 7,000 spp, not super successful Exclusively marine

P. Arthropoda ("jointed legs")

Not a clade At least one million species, could be as many as 10 to 30 million All major habitats, most abundant and successful in terrestrial habitats

SP. Hexapoda ("Six legged")

Occur in all habitats, very scare in marine, relatively common in freshwater, mostly terrestrial Characterized by having three body segments: head, thorax, and abdomen Complex metamorphosis, meaning many occur in a larva form that is very different from their adult form

C. Gastropoda

Occur in all major habitats Shell reduced or absent Variety of forging modes - scavengers, herbovires, predators Motile

Photosynthetic

On land, plants have more access to light for photosynthesis

Genetic drift

One species inhabits an area where they are sympatric and gene flow is possible between members of the population. Then a change in the geography or climate occurs that splits the population into geographic isolation, prohibiting gene flow between the two groups. Overtime, the two populations will diverge genetically due to differences in environmental pressures. If a change in the geography or climate allows the populations to becomes one again and they are so genetically different they can't produce fertile offspring with each other, then speciation has occurred and the populations have become two separate species.

Cephalochordata (lancelets)

Only 25 spp. Posses all four chordate traits in adulthood Motile throughout life Marine filter feeders - burrow into sand and mud and draw water in from protruding head Very simple organs

Class Cestoda (tapeworms)

Parasitic in gut of host by hooking into the intestine Rely on diffusion to get oxygen and nutrients and all of their energy to reproduction Constantly subject to natural selection, so their fitness is constantly evolving and improving

Clade Ecdysozoa

Possess a cuticle that they have to molt in order to grow.

P. Hrmicordata Traits

Possess two of the four chordate traits: Dorsal nerve cord - nerves passing through back region Pharyngial gill slits - series of openings in the throat region

High concentration of cellulose in the cell walls

Provides rigidity in individual cell, which push against each other to provide rigidity for the organism

Types of symmetry

Radial - symmetrical from all angles Not a derived trait because it is not unique to one group of organisms since both cnidarians and echinoderms have radial symmetry. Bilateral - two symmetrical halves Derived trait of clade bliateria because no other groups exhibit bilateral symmetry.

P. Hrmicordata Importance Evolutionarily

Seem very closely related to chordates because they posses two of the four chordate traits, but molecular molecular analysis reveals they are really closer to the echinoderms.

P. Annelida traits

Segmentation - body divided into clear segments Setae - mineralized hard structures orbrissels used in locomotion

P. Mollusca derived traits

Shell - structure made of calcium carbonate secreted by cells that offers protection to the organism Protects soft body from predators Prevents desiccation - the loss of bodily liquid Provides rigidity Foot - muscular structure that permits locomotion Evolved in many ways in the different classes Mantle - portion of the body that secretes the shell Radula - series of razors that is movable and used to scrape food off of rocks

P. Mollusks traits that make it so successful

Shell: 1) Provides protection 2) Allows for mollusks to use a variety of habitats, such as burrowing 3) Enables some mollusks, such as gastropods, to thrive in terrestrial habitats because it prevents desiccation, or drying out. Foot: Versital structure that provides a variety of ways for them to move around

What is wrong with Kingdom Protista taxonomically?

Since protists are the ancestors of the three other kingdoms, it is a paraphyletic group because it leaves out Kingdoms anamialia, plantae, and fungi.

Protist Ancestor of all animals

Since protists first appeared before all the other kingdoms, it is hypothesized that they are the ancestors of everyone. For animals, it is hypothesized that all animals evolved from choanoflagelates, colonial protists, which are single celled organisms that resemble the choanocytes of sponges. This means that Kingdom Protista is a paraphyletic group because it leaves out animals, plants, and fungi.

Bias in the Fossil Record

Small, soft-bodied organisms do not fossilize as well as large animals with hard structures.

Lack Stomata

Stomata are holes in the leaves that can open and close to receive CO2 for photosynthesis.

Gametophyte dominant

The Gametophyte stage, haploid stage, is more prominent than the, Sporophyte, diploid stage, in Bryophytes. When they are in their Gametophyte stage, they can photosynthesize. In their Sporophyte stage they cannot photosynthesis and are dependent on their Gametophyte for nutrients.

P. Platyhelminthes evolutionary importance

The ancestor of flatworms was most-likely free-living. This means that the two endoparasitic classes of flatworms, class trematoda and cestoda, are examples of degenerate evolution. They have lost traits that are needed in free living organisms and rely on diffusion to get nutrients from their hosts so that they can devote the majority of their energy to reproduction.

Evolutionary importance of sponges

The ancestor of sponges, and likely all animals, is the Choanoflagellate, a single celled protist that is very similar to the choanocyte cells of sponges. Choanoflagellates live in colonies anchored to a substrate and wave their flagella to filter feed. Sponges' choanocytes wave flagella to create a flow of water through the sponge so it can filter feed.

Binomial naming system

The binomial naming system was discovered by Linaeus in the 1700s. The first part of the name is the genius and the second part is the species the organism is assigned to. It is useful because it gives scientists from around the world a simple system to name organisms that they could all agree on.

Clade Protostomia ("mouth first")

The blastopore becomes the mouth in development

Clade Deurterostoma ("mouth second")

The blastopore becomes the mouth in the blastula stage of development

C. Cephalopoda convergence

The development of advanced sensory systems, specifically large brains and advanced camera-like eyes, in both cephalopods and vertebrates is an example of convergence. These similar traits are not due to common evolutionary decent. They are adaptations that allow these organisms to hunt, track, catch their prey as advanced predators.

Convergence

The development of traits that perform similar functions in relatively unrelated organisms due to similar ecological or environmental pressures. Convergence supports that phenetics is inconsistent with evolutionary history since organisms can develop similar traits without sharing a recent common ancestor, because of similar environmental pressures.

Convergent Evolution

The development of traits that perform similar functions in relatively unrelated organisms due to similar environmental pressures.

Evolution

The genetic change from one generation to the next

Natural Selection

The idea that fitness improves from one generation to the next. Three tenets: 1) Individuals vary genetically and phenotypically, meaning the outward expression of genes 2) Traits are heritable, meaning pass on to offspring 3)Evolutionary fitness varies, referring to the ability to reproduce and survive

Degenerative Evolution

The loss of a trait because it not longer has a fitness benefit. An example of degenerate evolution is in the endoparsitc classes of Phylum Platyhelminthes, class trematoda and cestoda. These groups have lost the complex structures of free-living organisms. As endoparisites, they can rely on diffusion to get nutrients already digested by their host and devote the majority of their energy to reproduction, improving their evolutionary fitness.

Importance of the outgroup

The outgroup is crutial in cladistics because by comparing the ingroup, the focal group, to the outgroup, the group just outside the ingroup, cladists can determine the derived traits of the ingroup, which are recently evolved and unique to the ingroup. The cladist then uses the derived traits to determine the evolutionary history of the ingroup.

Taxonomy

The process of classifying organisms

Speciation

The process of producing a new species. One way that speciation occurs is through genetic drift.

Radiometric Dating

The scientific process where decaying isotopes of elements are used to establish absolute dates. Almost all isotopes are stable, however some are unstable. Those that are unstable decay, meaning they change from the atom of one element, to the atom of another element. Each isotope decays at a certain rate, which is measured as a half-life, or the time it takes for half of the unstable atoms to decay into the new element. Since the rate of decay is predictable, scientists can compare ratio of the starting isotope, called the parent isotope, and the isotope of the new element, called the daughter isotope, to determine how much time has passed.

Major groups in Bryophytes

The superphylum Bryophytes contains three phyla, Mosses, liverworts, hornworts. Mosses are the most diverse and abundant

Why is it awkward and misleading to refer to "land invasion"?

The word invasion implies that this was a goal-oriented process, which is the concept of teleology. In reality, plants' transition to terrestrial habitats was a passive process in which plants were more successful in dry, terrestrial habitats Exaptation - the procession of some trait that happens to be beneficial in another habitat

Process of alternation of generations

To go from the diploid to haploid stages, gametes, single haploid cells, join to form the zygote, which then goes through mitosis to become the multicellular sporophyte (diploid stage). Then meiosis occurs, the splitting of genetic tissue, restoring the haploid stage.

Homology

Traits that evolved from a common ancestor that have changed over time and may no longer have the same function Example: the ulna in a human and the ulna in a cat. These two structures have the same evolutionary origin, however the ulna in a cat has a different function than our own because it is weight bearing and ours is not.

Analogy

Traits that have the same function, but do not have the same evolutionary origin Example: Bird wings and butterfly wings have the same function, however they do not have the same evolutionary origin. Fusiform shape

P. Platyhelminthes traits

Triploblastic - ectoderm, mesoderm, endoderm Organs - combination of tissue layers that are combined to carry out a specific function High surface area to volume ratio Flat worms are flat, their cells are close to the outside environment, so that they can rely on diffusion to get oxygen and nutrients.

P. Mollusca

True monophyletic clade 100,000 spp, highly successful Mostly marine, some freshwater and terrestrial

P. Cnidaria Traits

True tissues but no organs Radial symmetry - not derived Cniderain Life Cycle: polyp and medusa forms Different classes spend different portions of their lifetimes in the two stages. Derived traits

Bryophytes (seedless vascular plants) lack many of these traits which vascular plants do exhibit:

Vascular tissue Cuticle Stomata Cannot protect from desiccation Seeds, leaves, and roots

What does vascular tissue allow a plant to do?

Vascular tissue allows the plant to distribute water and nutrients provides structure. Both of these benefits allow a plant to grow larger.

SP. Vertebrata

Vertebrae - bone structure that protects spinal column Cranium - braincase Cephalization - have a distinct head region that is much larger than the rest of the body, because of a well developed, large brain that is encased by a cranium Cephalization allows for vertebrates to have advanced motility and become advanced predators with all of their sensory organs concentrated in one area so that they can hunt and consume prey Jaw - allows for vertebrates to forage multiple different ways

SP. Crustacea

Very abundant and diverse in marine habitats, some in freshwater, a few terrestrial (rollie pollies) Two sets of antennae Important to humans: Food source for humans Important constituents of the food web as food for many other organisms on which we depend

Why is Kingdom Protista important evolutionarily?

We are not sure exactly when protest first appeared, but they evolved before the other kingdoms and are the ancestors of everything.

Wings of Insects

Wings is the traits that makes insects so successful. wings (two sets) - allow for many functions that help survival Enables them to escape predators, migrate from one geographic area to another, access resources, and use environment more richly

Relative vs Absolute dates

With radiometric dating, scientists can determine absolute dates, precise dates, that organisms first appeared. Before radiometric dating, scientists could only determine relative dates based on the level of sedimentation a fossil was found in.

2 different types of vascular tissues

Xylem - water conducting Phloem - moves sugar around from leaves to roots

Sporophyte

diploid

Gametophyte

haploid

Demands on a free-living vs parasitic animal

parasitic: since they are not free-living, they do not need complex traits to cope with the outside environment. They can rely on diffusion get nutrients already digested by their hosts and devote the majority of their energy to reproduction.

Charophyte similarities with land plants

structure of sperm cell wall is relatively high in cellulose peroxisome - organelle (intercellular structure that carries out a specific function) that increases efficiency of respiriation