Quiz 1 Flashcards
Theory
A body of thoughtfully tested and verified explanations for observations of the natural world- often incorporate conclusions from a variety of scientific fields
- does not imply lack of certainty; is cross-referenced with many phenomena- building greater certainty through modification rather than rejection
World view
A conceptual framework of ideas
The theory of biological evolution
All life shares common ancestry- linked by lines of dissent and has arisen from previous forms; processes of biological evolution that change populations of species over time and create new species (diversity)
Evolution
a connection of interconnected ideas
microevolution
evolutionary change that occurs within a species
- ex. Tomcod fish in Hudson River have evolved to withstand the toxic PCBs in their food source (relatively short period of time)
macroevolution
evolutionary change that results in the origin of a new species
- ex. Tomcod type of ray-fish - all have a common ancestor and larger changes as result of many microevolutionary steps
Evolution of species
evolution of fish species from a common ancestor over a long period of time
Biological Evolution
the change in heritable traits of a population over successive generations
elements of biological evolutions
change, heritable traits, population, successive generations
Change in population
Evolution= changes at the level of a population: “What portion of the population holds this trait?”
change in a heritable trait
change as a result of biological evolution; change is genetically sound/heritable
successive generations
change in population over generations; requires time
Natural selection
only evolutionary process that leads to adaptive evolution -> organisms evolve to be better suited for their environment as advantageous traits become predominant over time
Adaptation
a heritable trait favored by natural selection because it provides some function that helps the animal survive and reproduce in its environment
Elements of evolution by natural selection
VISTA Variation Inheritance Selection Time Adaptation
Variation + Inheritance
random mutation produces variation of a gene that is passed on/heritable
Selection
selective pressure and differential reproduction; environmental pressures cause individuals with a particular variation to have an advantage- making them better able to survive and reproduce
Selective pressure
external factors that contribute to the selection of which individuals have an increased success of surviving and reproducing offspring
differential reproduction
When reproductive success is not equal in a population (effect of selective pressures)
Time
Over time, advantageous traits of generations get passed to greater and greater numbers of offspring; over time, the population changes; strength of advantage determines speed at which population changes
Adaptation
overtime traits become more common, resulting in a population better suited to its environment
mutation is..
random
natural selection is..
not random- favors the mutations beneficial to the individuals
How is Natural selection limited
can only choose between the population’s existing genetic variations and whatever new genes arise through mutations
genetic makeup of a population
changes over generations, so the majority of individuals are well-suited to survive/ reproduce in their environment
Phylogeny
Evolutionary history and relationships between groups of animals
when did a common ancestor of all living organisms line
4 billion yrs ago
Evolutionary tree
visual representation of evolutionary history of lines of dissent
more recent common acestor=
more closely related groups of animals
Family tree does not equal phylogenetic tree why?
family tree means relationship between individuals; phylogenetic tree means relationship between different types of animals
Node
point in history where different animals shared a common ancestor on tree
common ancestor
a past specific type of animal, not an individual
Taxon (plural taxa)
a groups of animals given an officiation name of classification
creation of taxa
at some point, the population of the node diverged- taking many generations undergoing many evolutionary changes to become separate taxa
Phylogenetic line
representative of the multiple generations it took to become separate taxon
root
ancestor that all lineages on the tree share
Determining which animals share the most recent common ancestor
whichever node is closest to the present time is the most recent common ancestor
rotation of branches around a node
doesn’t change evolutionary relationship
time direction
root to tip; present taxa at tips
hashmarks
characteristics change acquired between common ancestor and taxon/a
common characteristics
common ancestor
most common charicterisitcs
earliest common ancestor
Clade
a group of organisms that includes a common ancestor and all the descendants of that ancestor
clade on a tree
includes node representing common ancestor plus all taxa that branch from it
being nested
a clade within a clade is nested
levels of classification (biggest to smallest)
superfamily, family, subfamily, tribe
method for giving taxa names of classification
based on evolutionary relationships (share a more recent common ancestor from in -> out)
pruned tree
a tree representing the same evolutionary relationships with a subset of taxa from the original tree
Homologous characters
similar characters shared by two groups of animals because their common ancestor has the trait
Analogous characters
two types of animals have a similar characteristic that is not due to a common ancestry -> evolved independently in two different lineages due to similar selective pressures
convergent evolution
evolution of analogous traits => both lineages “converged” on the same adaptation separately
three domains of life
Bacteria, Eukarya, Archaea
Bacteria and Archaea domains
single-celled organisms, DNA not in membrane-bound nucleus
what are archaea best known for
living in extreme habitats (extremely hot, cold, acidic, alkaline, salty, deep) but can live in moderate areas too like humans
Eukarya (eukaryotic organisms)
DNA within membrane-bound nucleus in the cell; plants, fungi, animals
Autotrophs
make their own food, ie, plants (use CO2 as food and sunlight as energy)
Heterotrophs
consume other organisms for energy => Fungi and Animas
Absorptive heterotrophs
Fungi => secrete digestive enzymes outside of the body, then consume digested nutrients (on dead animals/plants)
ingestive heterotrophs
Animals => bring food inside the body then digest it
Animals
a eukaryotic heterotroph that ingests food
Estimate animal first appearance
580 million years ago (fossil record) to 1.2 billion yrs ago (molecular record)
Metazoa
the clade of the common ancestor of all animals and its descendants (every animal ever)
Eumetazoa
clade nested within Metazoa of animals whose cells form tissue => all animals except sponges are composed of true tissue
Body plan
the design/ architecture of closely related animals exhibiting a group of distinctive characteristics which defines them as a group structurally and functionally
Features of phylum’s body plan
body symmetry, presence or absence of true tissue, type of support, organization of nervous system, pattern of development
Phylum
group of taxa in a clade with a unique body plan
tasks of staying alive
getting nutrients, gas exchange, excretion
Nutrients
substances used for energy and to build structures required to sustain life (carbohydrates, proteins, lipids)
Feeling strategy
how do animals obtain food and ingest it
chemical digestions
carbohydrates->simple sugars Lipids->fatty acids proteins->Amino acids
digested nutrients
small chemical subunits of nutrients
distribution of nutrients to all parts of the body
cite of chemical digestion -> all cells of the body
elimination of indigestables
how they are eliminated
gas exchange
Animals need O2 from the surrounding environment and to get rid of metabolically produced CO2 from creating energy
Excretion of nitrogenous waste
“Excretion” = removal of nitrogenous waste “nitrogenous waste” = excess amino acids converted into other nitrogen-containing molecules
Phylum porifera
sponges
porifera
“pore-bearer”
how many species of sponge
9,000
sponge environments
mostly restricted to marine environments => reefs, bottom surface of sea, shoreline; few species inhabit freshwater => lakes, rivers, streams, and bogs attached to submerged rocks, logs, sticks, or vegetation
sponge level of orginization
multicellular (like all animals); specialized cells, but their cells are not organized into true tissue (metazoa, noy Eu)
symmetry
the regular arrangement of body structures relative to the axis of the body; if animals can be split along one plane so that the resulting halves are like one another, the animal has symmetry
asymmetry
no plane of symmetry
sponge symmetry
For the most part, sponges are asymmetric
sponge shape and support categories
spongin and spicules
spongin
flexible fibers composed of protein ‘collagen’ secreted by special cells of the sponge forming a network of flexibility and support in mesohyl
spicules
mineralized components of the skeleton, secreted by specialized cells; composed of silica or calcium carbonate; are various shapes
sponges with only spongin vs spongin and spicules
only spongin = soft and flexible
sponge nervous system
no neurons, no nervous system
morphology of sponge
cylinder with body wall and large central cavity
Body wall of sponge
three layers; inner, middle, outter
inner layer of body wall
single layer of cells called choanocytes (ko-ann-o-sites)
middle layer of body wall
a gel-like non-living substance composed primarily of collagen and secreted by sponge cells called mesohyl; some cells move through it
Outer layer of body wall
single layer of cells called pinacocytes (pin-a-co-cytes)
Pinacocytes
thin, tightly jointed cells forming outside of sponge- like skin
choanocytes
play a significant role in getting nutrients
sponge pores
openings in body wall formed by another type of specialized cell that allows water to flow through a canal and into central cavity
Amoebocyte
specialized cell capable of movement through mesohyl
Aquiferous system/ canal system
system of canals through which water flows as it passes through the sponge’s body
sessile
attached to surface/ doesn’t move around
effect of sessile nature on sponges
Rely on water flow to bring them nutrients and rid them of waste
osculum
common opening through which water leaves sponge, carrying waste and CO2
gas exchange in sponges
direct diffusion
diffusion
the net, passive movement of molecules from a region of high concentration to a region of lower concentration (down its concentration gradient)
how is diffusion possible
Each cell of the body needs a constant supply of O2 to convert energy in food to ATP to live; cell’s constant use of O2 means there is always a higher concentration in the surrounding water of O2 than inside the cell
Direct diffusion gas exchange
O2 diffuses into, and CO2 diffuses out of each cell directly => sponges are only organized at the cellular level, meaning no tissue, meaning no specialized gas exchange chamber, meaning every cell for themselves
what property of diffusion constrains sponge body wall
The process is slow, so each cell layer can only be one cell thick in order to survive
Sponge structure that allows for obtaining nutrients
Choanocytes: single flagellum (thin, threadlike) that moves around in a whip-like fashion surrounded, at one end, by a collar of microvilli (short, thin extensions)
function of choanocytes
the beating of all of the choanocyte flagella creates the current of water flowing through the sponge, the microvilli collar traps the food particles suspended in the water
suspension feeding
feeding strategy of grabbing food suspended in water
Active suspension feeding
flow of water is created by the action of the choanocyte flagellum to obtain suspension feeding
Songe distribution of trapped food to cells
amoebocyte picks up membrane-enclosed food and distributes it to other cells of the body by traveling through the mesohyl
songne chemical digestion
inside each cell, including the choanocytes, the food particles are chemically (enzymatically) digested and products are used to build parts of the cell and ATP
Elimination of undigested material
Indigestible material is expelled from the cell and leaves the sponge with water flowing out of the osculum
Excretion by sponges
proteins => amino acids => excess amino acids => ammonium => ammonium diffuses from higher concentration (inside cell) to lower concentration (surrounding water)
number of species of Cnidaria
11,000 20 are freshwater
fossil history of cnidaria
700 million yrs (very important to life on earth today)
organizational level of body plan in cnidaria
tissue; morphologically and developmentally similar cells that are organized for specific function
Animal development
the formation of germ layers becoming tissue layers
fertilization
egg + sperm
cleavage
the replication and division of the fertilized egg to create more cells
blastula
hollow ball of cells produced by cleavage; one layer of cells surrounding a fluid-filled space; cells of blastula = building blocks of animal (each has same DNA as fertilized egg)
Gastrulation
formation of layers; cells at one end of blastula fold inwards, producing a 2-layered embryo; these two sheets = ‘germ layers’
germ layers cnidaria develop from
“ectoderm” is the outer germ layer; “endoderm” is the inner germ layer
Dipolblastic
animals that develop from two germ layers; each germ layer gives ride to specific layers of the body
two body forms of cnidaria
Polyp and medusa
polyp
cylinder-like body with mouth pointing up and tentacles waving above; immobile (sessile)
Medusa
bell-shaped body with mouth pointing down and tentacles hanging below; free swimming/floating; rely on current to carry them
cnidaria symmetry
radial
radial symmetry
body parts arranged around the central axis; can be bisected along the axis in more than one plane to produce identical halves
body wall composition
inner, outer, and middle layers of TISSUE
inner tissue layer
gastrodermis; developed from endoderm (single layer)
middle tissue layer
mesoglea; space between layers; non-living, gelatinous
outer tissue layer
epidermis; developed from ectoderm germ layer
inner space of body
gastrovascular cavity
gastrovascular cavity
opening serves as both mouth an anus; in most, surrounded by tentacles
alternation forms
some cnidaria alternate from one form to another (polyp, medusa) at different stages of their lifecycle => live different lifestyles in different forms => can exploit different environments => adults/larva don’t compete => not all cnidaria alternate between polyp/medusa
organization of cnidarian nervous system
diffuse, non centralized
diffuse nervous system
lack a true brain; have a system of separate, individual neurons throughout the body; “nerve net”
attributes of a non centralized nerve system
stimulation of a sensory cell on one side of the body = signal spreading over entire body => frequency of stimulation determines how much of body responds; more frequent = more surface area of body affected
– are capable of complex movement and behavior
cnidarian muscles
antagonist muscles
antagonist muscles
contraction of one muscle + relaxation of its opposition
muscles in cnidaria
longitudinal and circular
longitudinal muscles
run lengthwise in the cnidaria
circular muscles
run around the cnidaria
cnidarian skeleton
hydrostatic skeleton
hydrostatic skeleton
fluid support system; any change in pressure applied to an enclosed, noncompressible (volume of liquid does not change if pressure is applied to it) fluid is transmitted to every portion of the fluid and the walls of the containing vessel
hydrostatic skeleton in an animal
compartment if fluid-filled intestinal space, closed, or can be closed to the outside => muscles, stimulated by nerves, in walls of this space apply pressure to fluid => for compartment to change shape in different direction, another set of muscles, oriented in a different direction, is necessary
Hydrostatic skeleton used by anemone
to maintain its shape/structure through support while also producing a change in shape
requirements for a hydrostatic skeleton
1.) Enclosed cavity containing a substance (usually water) that can not be compressed 2.) The volume of fluid in the cavity should remain constant while pressure is being applied. Therefore, the compartment must remain closed (1/2 achieved in anemone by gastrovascular cavity and ability to close mouth). 3.) The cavity is located between antagonistic muscles 4.) nerve cells to stimulate muscle to contract (cnidarians have both) 5.) the cavity must be surrounded by a flexible outer body membrane so that the outer body wall can deformed (change shape) (cnidarians outer body wall is flexible not rigid)
Important feature of water
can not be compressed
getting and ingesting food by anemone
Nematocysts is expelled to capture prey (or in self-defence) => Once captured, food is brought into mouth, then Gastrovascular cavity
nematocyst
a barbed, venomous, coiled thread-like structure within the epidermis cells that enables the ability to capture prey/defend;
chemical digestion in amnemone
gastrodermis, the inner layer of tissue on GVC, secretes enzymes that chemically break down nutrients
distribution of digested nutrients in anemone
GVC branches to all parts of the body (including tentacle) => nutrient molecules transport to every cell in the body using these branches => aided by cilia (hairlike extensions from surface of gastrodermis cells moving rhythmically) => cells absorb digested nutrients from GVC (serves both digestive and circulatory purposes)
type of digestive system in cnidaria (anemone ex)
incomplete
incomplete digestive system
only one opening to GVC, serving as both the mouth and anus
constraint put on cnidaria by incomplete digestive systems
eat a lot at once, digest, then expel => no continuous eating
gas exchange in cnidaria
direct diffusion => no specific structure for gas exchange
excretion of waste in cnidaria
proteins => amino acids => nitrogenous waste => ammonia
siymiosis
interaction between two living organisms living in close proximity
zooxanthellae
single=celled, photosynthetic, marine algae
relationship between zooxanthellae and cnidaria
symbiotic; zooxanthellae live on cnidarian tissue; algae transfer photosynthetically-derived, energy-rich molecules to cnidarian host, in return for access to nitrogen, phosphorous, and other cnidarian metabolism-driven nutrients and protection from the environment
mutualistic, symbiotic relationship between Cnidarian and Zooxanthellae
Cnidaria get their color from zooxanthellae, and many rely on zooxanthellae for nutrients; some receive 70-90% of nutrition from zooxanthellae products
coral reefs
hard corals, types of coral that builds reef; extract calcium from surrounding seawater to create hardened skeleton for protection and growth => created by millions of polyps forming large calcium carbonate structures => home for hundreds of thousands, if not millions of other species
coral polyp
individual cnidarian creating coral
coral colony
many polyps of the same species hardening together
coral reef
groups of hardened coral species
Difference between coral polyp and anemone
only difference is that anemone don’t create a hardened skeleton
environmental conditions required by reefs
shallow waters (30-100 ft), sunlit waters => reef-building corals require warm weather water conditions to survive => optimally between 73-90 degrees Fahrenheit for all coral => require clear water (sediment can cloud waters, wastewater discharge near reef can contain too many nutrients, causing seaweed to overgrow reef => reefs occur in less than 1% of ocean
bleached coral
Not dead- but expulsion of Zooxanthellae (because they go overboard and start producing toxins) leaves the coral in a nutrient debt and can’t survive for much longer (can give color back and be saved, but needs immediate action)
climate change
The warming of the earth from increased trapped radiation due to the reverb caused by an excess amount of greenhouse gasses in the atmosphere, which are created by the burning of fossil fuel
