Lecture 2 Flashcards
what are the 4 eukarya supergroups?
-excavata
-SAR
-archaeplastida
-unikonta
what does SAR contain?
-stramenopile
-alveolate
-rhizaria
what are the two major clades apart of the unikonta?
-amoebozoans
-opisthokonts
what are some examples of species within the amoebozoans? what is a key feature of these species?
-slime moulds
-amoeba
-have lobular pseudopodia
what is lobular pseudiopodia?
-lobular protrusions (feet)
what are some examples of species within the opisthokonts?
-animals
-fungi
-closely related protist groups
what are examples of typical animal characteristics?
-multicellular
-no cell walls (plasma membrane)
-can move
-heterotrophic
-embryonic tissue
what junctions are present in animals? what is the purpose of these junctions?
-gap junctions (communication)
-tight junctions (hold/interconnection)
why is movement important in animals?
-need directional motion to seek for new habitats in case of stressful environments
-survival (predation)
-find food + water
-find mates (reproduction)
what does it mean to be heterothrophic?
-obtain energy from energy releasing foods/substances
-cannot produce their own food
what are the 3 embryonic tissues?
-endoderm
-mesoderm
-ectoderm
what are the basic concepts of the animal life cycle?
-have a diplontic life cycle
-form from gametes into a zygote
-have a juvenile and adult form
what does is mean to have a diplontic life cycle?
-to have a lifestyle that is dominated by the diploid stage
what are the male and female gametes? are they haploid or diploid?
-sperm (male)
-egg (female)
-diploid
what occurs between the juvenile and adult forms of an animal? what is an example of an animal that goes through this?
-a stage of change called metamorphosis
-tadpole + frog
what is multicellularity used to describe?
-an organism that is composed of many cells
what advantages does multicellularity have?
-adds complexity to forms and processes
-allows organisms to survive and thrive
where did multicellularity first develop? what clade is closely related?
-first developed in metazoa
-closely related to animalia
what did the cells of multicellular organism resemble?
-the single celled choanoflagellates
what does the ectoderm form?
-epidermis
what does the endoderm form?
-interior organs and muscle systems
-inner cells help form gastrula (gastrovascular cavity)
what is the best outgroup for the animal clade?
-porifera (shared common ancestor)
what are 3 key features of choanoflagellates?
-have a flagella
-have a collar of microtubules
-live in colonies
what is the evidence that supports the evolution of multicellularity from choanoflagellates?
-similar cell morphology (shape, structure, form, size)
-unique animal cell morphology (no cell wall + no plastids)
-DNA sequence homology
what are plastids?
-small organelles containing pigment or food (chloroplasts)
what are the key aspects of the porifera phylum?
-known as the sponges
-2 main cell layers + a middle region
-have random growth (asymmetrical)
what are the two cell layers found in porifera?
-epidermis
-choanoderm
what is the purpose of the choanoderm layer in porifera?
-draws in food particles to be passed through amoebocytes
what is found in the middle region of porifera?
-porocytes
-mesohyl
what is the function of porocytes?
-control the water entering the spongocoel (large central cavity)
what is contained within mesohyl/
-amoebocytes
-hardened spicules
what is a special characteristic of sponges?
-have totipotent cells
-a single sponge cell can create a new sponge
what are totipotent cells?
-cells that can differentiate into different cell types
-ability to self organize
-reassembling is spontaneous
what much be provided in order for reorganization to occur within totipotent cells?
-lots of activity
what do sponges lack?
-radial symmetry
-true tissues
what does it mean to not have true tissues?
-no organs
-no muscles
-no nervous system
what are the key aspects of the cnidaria phylum?
-diploblastic
-have radial symmetry
-can have 2 body shapes
what does it mean for an organism to be diploblastic?
-they have 2 embryonic germ layers (2 tissue systems)
-only have an endoderm and ectoderm
what is the purpose of the ectoderm in development?
-covers the surface of the embryo
what is the purpose of the endoderm in development?
-lines the pouch formed during gastrulation
-lining of the digestive tract, liver, and lungs
what are the 2 cellular layers and the 1 non-cellular layer of the cnidaria phylum?
-epidermis + gastrodermis = cellular
-mesoglea (jelly) = non-cellular
what are the 2 body shapes that can be taken on in the cnidaria phylum?
-polyp form
-medusa form
what species take on the polyp body form? what are the basic aspects?
-anemones + hydras (crawling animals)
-cylindrical
-mouth/anus faces up
-aboral side is for movement
what species take on the medusa body form? what are the basic aspects?
-free swimming jellys (free moving animals)
-bell shape
-mouth/anus faces down
-tentacles point down
what is radial symmetry? what are its key aspects?
-several planes of symmetry around 1 central body axis
-no right or left side
-have a top + bottom
what is the top side of an radial species referred to as?
-oral side (mouth and anus)
what is the bottom side of a radial species referred to as?
-aboral side (furthest from mouth)
where did radial symmetry first evolve?
-cnidaria phylum
what are tissues?
-groups of specialized cells that perform a specific function
-can be isolated from other tissues by membranous layers
how many groups, systems, and membrane layers of tissues do parazoa have?
-1 group
-1 system
-no membranes
how many groups, systems, and membrane layers of tissues do eumetazoa have?
-1 group
-2 systems
-membranes
what two major events formed eumetazoan tissues?
-cleavage
-gastrulation
what is cleavage?
-numerous mitotic divisions
what does gastrulation form?
-primitive gut (primary digestive tube)
-blastopore (mouth)
what 2 embryonic germ tissues do eumetazoans have?
-ectoderm (outer layer)
-endoderm (inner layer)
what does it mean for an organism to be triploblastic?
-have 3 germ layers (3 tissue systems)
-ectoderm, mesoderm, endoderm
what is the purpose of the mesoderm?
-fills the space between the ectoderm + endoderm
-forms muscles + most inner organs
what are examples of organisms who are triploblastic?
-flatworms
-arthropods
-vertebrates
what are grades of organization?
-organisms that only share key biological features
-no relationship between organisms
-a result of convergent evolution
what is the reason for grades of organization? how do they arise?
-develop to overcome obstacles
-when 2 unrelated groups have found a similar solution to their own unique problems
what are examples of grades of organization?
-coelom
-segmentation
-wings
