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Occurs when selection causes differential survival of a particular phenotype.
- Similarityin organisms due to common ancestry
Parallel evolutionary solutions to similar problems.
Ex: Analogous structure of seals and sharks
Group of interbreeding individuals of the same species that produce fertile offspring.
random changes in allele frequencies over time
Sum of all the alleles in a population and their relative proportions.
Condition where a species may originate from an accident during cell division that results in extra set of chromosomes
The majority of animals live in aquatic habitats. Invertebrates are by far the most successful group and include more than 95% of known animal species.
Characteristics of the Kingdom Animalia: Nutrition
Heterotrophs that ingest food and digest it with the aid of internal enzymes.
Characteristics of the Kingdom Animalia: Cell Structure
Multicellular eukaryotes that lack cell walls and rely on proteins for structural support.
Characteristics of the Kingdom Animalia: Specialized Cells
Nerve cells and muscle cells are unique to animals.
Characteristics of the Kingdom Animalia: Reproduction
Predominantly sexual with a dominant diploid stage. Sperm cells are flagellated and eggs are nonmotile.
Characteristics of the Kingdom Animalia: Development
Embryological Cleavage: Mitotic divisions of a zygote without cell growth between divisions. Results in a gastrula where enfolding forms embryonic tissue layers that differentiate into specific structures as development proceeds.
Characteristics of the Kingdom Animalia: Hox Genes
Suites of Hox genes regulate body form and produce diverse morphologies.
What are the primary points of diversion between animals? (the different morphological traits that help us understand animal relationships)
- Symmetry: asymmetrical, radial, or bilateral body form (know the difference)
- Tissues: may lack true tissues, be diploblastic, or triploblastic
- Body Cavity: may be acoelomate, pseudocoelomate, or coelomate
- Embryological Development: may be protostome or deuterostome
- Molecular Evidence: splits the protostomes into two clades: the lophotrochozoa and the ecdysozoa
Animals share a common ancestry and comprise a monophyletic clade called metazoa.
Describe how sponges are related to the rest of Metazoa.
Except for sponges, animals have true tissues and are placed in the clade eumetazoa. Basal eumetazoans studies in this lab are the Cnidarians who are diploblastic and have radial symmetry. Sponges are basal animals. They lack true tissues and are usually asymmetrical.
Consists of protostomata and deuterostoma. Most of the eumetazoans fall under this category (excluding Cnidaria).
- They are bilaterally symmetrical and triploblastic
- Body plans may be acoelomate, pseudocoelomate, or coelomate
What clade does Ecdysozoa and Lophotrochozoa belong to?
Distinguish between the two clades of sponges.
Molecular evidence suggests that sponges have at least two clades:
- Silicea: “glass sponges” are characterized by a skeleton composed of silica spicules and live mainly in deep water environments
- Calcarea: possess spicules composed of calcium carbonate and live in shallow waters
Describe what molecular and morphological studies indicate about the ancient animal ancestor of Silicea and Calcarea sponges.
The ancient animal ancestor resembled a modern collared flagellate (choanoflagellate). The primary link are the filter-feeding cells of sponges called choanocytes (which are not present in plants or fungi).
- Diverged from the rest of the animal lineage before the development of true tissues
- All are aquatic
- Adults are sessile: they live their lives attached to a substrate
- Sponges reproduce asexually by budding or fragmentation
- Sexually they are serial hermaphrodites which means they possess both male and female gonads, and function as one gender before switching to the other (no self-fertilization)
In addition to choanocytes, all sponges have Amoebocytes that engulf and digest food, and transport nutrients through the sponge’s body. They also manufacture skeletal fibers, which may be made of calcium carbonate, silica, or a protein called sponging depending on sponge type.
Describe the system of canals that sponges are comprised of.
Water is drawn through incurrent pores into the central spongocoel before exiting out the osculum. Choanocytes line the inner spongocoel and strain particles from the water.
What are the Cnidarians named after?
- The specialized cells, cnidocytes, that contain stinging organelles called nematocysts.
- They are the first group of animals to show diploblastic development which results in two true tissue layers forming from embryonic ectoderm and endoderm.
- The primitive nervous system consists of a neural net at the interface of these two tissue layers.
They are radially symmetrical animals with a gastrovascular cavity that serves both as the gut and a hydrostatic skeleton. Cnidarians have two variations on the basic body plan:
- the sessile polyp
- the mobile medusa
Describe the four classes of Cnidaria.
Hydrozoa – Obelia, Hydra: Both polyp (dominant) and medusa (less common) stages, polyp stage often colonial
Scyphozoa – Jellies: Reduced polyp stage; dominant medusa stage; free swimming medusa. Statocysts are sense organs that help determine the jelly’s position in the water column
Cubozoa – Box Jellies, Sea Wasps: Box-shaped medusa; eyes
Anthozoa – Sea Anemones, Most corals: No medusa stage; sessile; often colonial
- Ecdysis means to molt, so this clade includes animals that shed a tough outer cuticle, enter a growth period, and then secrete a new cuticle
-Triploblastic: which means they have three tissue layers: endoderm, mesoderm, and the ectoderm
Nematodes and Arthropods. Share:
What are the two patterns of embryonic development that generate a true coelom?
- Protostome development results from the splitting of the embryonic mesoderm. As a result, it is considered a schizocoelous (schizo=split) coelom and occurs in most of the remaining animals.
- Deuterostome development results from mesodermal outpocketings of the primitive gut, or enteron, and considered enterocoelous.
What is the difference between protostomes and deuterostomes with regards to cell division?
Protostome – Determinate cell division: mitotic division of the protostome zygote produces daughter cells whose fate is committed to the production of a specified body part [also have a spiral cleavage pattern]
Deuterostome – Indeterminate cell division: division produces stem cells whose fates are not fixed at the time of division [also have a radial cleavage pattern]
Protostomata – Ecdysozoa – Nematoda: Roundworms
In roundworms, the appearance of a functional body cavity represents a significant evolutionary milestone.
Complete digestive system, separate sexes, and a pseudocoelomate body plan: pseudocoelomates are characterized by a digestive tract lines by endoderm and a body cavity, the pseudocoel, that is partially lined with mesoderm.
Protostomata – Ecdysozoa – Arthropoda: Spiders, Insects, and Crustaceans
As the most successful animal group on the planet, the arthropods share three basic characteristics:
2. A Chitinous Exoskeleton
3. Jointed Appendages
Describe the characteristics of the four arthropod subphyla.
Chelicerates – Spiders, etc: Body has 1-2 parts; 6 paired appendages, chelicerae; pedipalps; 4 pairs of legs
Myriapoda – Millipedes and Centipedes: 1 pair antennae and mandibles; millipedes have 2 pair legs/segment; centipedes have 1 pair legs/segment
Hexapoda – Insects: Body has 3 parts, 1 pair antennae; 3 pair legs, two pair wings
Crustacea – Crabs, etc: Body with 2-3 parts; 2 pair antennae; mandibles, 3+ pair of legs
Characteristics of Arthropoda – Chelicerates
- Lack antennae and mandibles
- The first pair of appendages, the chelicerae, are modified to form pincers or fangs
- They share a two-part body plan with an anterior cephalothorax and posterior abdomen
Characteristics of Arthropoda – Myriapoda
- All living members are terrestrial
- They have one pair of antennae and three pairs of modified appendages that serve as mouthparts, including a pair that is modified into jaw-like mandibles
Characteristics of Arthropoda – Hexapoda
- Insects are the most diverse invertebrates and comprise nearly 90% of all animal species
- Their success is due to specialized locomotor and feeding appendages, as well as advanced sensory organs
- The single most important factor in their success is their ability to fly
Characteristics of Arthropoda – Crustacea
- Dominant arthropod in marine environments, but also occur in freshwater and moist soils
- Have two pairs of antennae, and biramous (branched) appendages modified for purposes such as feeding, swimming, reproduction, etc.
Bacteria and Archaea
Lack membrane bound organelles and do not have nuclei
Bacteria that require oxygen
Break down organic compounds from the environment
1. Supergroup Excavata
2. Supergroup Chromalveolata
3. Supergroup Rhizaria
4. Supergroup Unikonta
Mainly parasitic, reduced mito
1. Subgroup Diplomonadida
2. Subgroup Parabasala
3. Subgroup Euglenozoa
- characterized by an “excavated” groove on one side of cell body
- Diplomonads and Parabasalids have modified mitochondria while the Euglenozoans have unique flagella
Examples: parasites such as Giardia (dimplomonad), and other predatory and photosynthetic species
2. Kinetoplastids- large single Mito
1. Subgroup Alveolata
2. Subgroup Stramenoila
- originated by an ancient secondary endosymbiotic event
- includes diatoms, Plasmodium (causes malaria), Phytophthora (caused potato famine)
1. Dinoflagellates 2. Apicomplexans
1. Diatoms 2. Golden Algae 3. Brown Algae 4. Oomycetes
1. Subgroup DInoflagellates: Two flagella, cellulose armor
2. Subgroup Apicomplexans: Animal parasites, sporozoite is infectious stage.
3. Subgroup Ciliates: Cilia used for feeding, 2 nuclei
Alveolata: membrane bound sacs that stabilize cell
EX: Plasmodium Vivax and Paramecium
1. Oomycetes (watermolds): Cell wall made of cellulose
2. Bacillariophytes (diatoms) : Cell wall made of Silica plates,
Mainly marine habitats, have shells (tests), and pseudopodia (false feet).
1. Subgroup Cercozoa: Test made from Calcium Nitrate
2. Subgroup Radiolaria: Test made of Silica
3. Subgroup Forminifera:
- contains many species of amoebas, which have threadlike pseudopodia for movement and prey capture
1. Cercozoans – includes most of amoeboid and flagellated structures, heterotrophs
2. Forams – or foraminiferans, named for their porous shells called tests, which are hardened with calcium carbonate
3. Radiolarians – delicate, symmetrical internal skeletons made of silica, radial pseudopodia
Amoebozoans whose members are characterized by having lobe-shaped pseudopodia.
1. Subgroup Amoebozoa: No test present, lobe shaped pseudopodia.
- group of eukaryotes that includes amoebas that have lobe or tube shaped pseudopodia
- closely related to animals and fungi
1. Slime molds 2. Gymnamoebas
1. Nucleariids 2. Fungi
Two subgroups of green algae:
1. Subgroup Chlorophyta
2. Subgroup Charophyta
- group of eukaryotes that contains green algae, red algae, along with land plants
1. Red Algae
2. Chlorophytes (Green Algae)
3. Charophytes (Green Algae)
4. Land Plants
Resemble those of plants, 4 Genus:
1. Genus Chlamydomonas
2. Genus Spirogyra
3. Genus Volvox
4. Genus Ulva
Higher percentage of cellulose in cell walls.
More closely related to terrestrial plants.
Oogania produces eggs, Antheridia produces sperm
Produces haploid (n) gametes by Mitosis.
Gametes fuse to form Zygote (2n).
Zygote undergoes Mitosis to form a diploid sporophyte, which produces spores (n) by meiosis.
Lack vascular tissues
Dominant Gametophyte, Reduced Sporophyte
Require water for fertilization.
Xylem and Phloem both present.
First "True" vascular tissue
Evolutionary Trend in Gametophytes and Sporocytes
Mosses have huge gametophyte and small sporophyte.
Ferns have small gametophyte and have large sporophyte.
1. Group Cycadophyta
2. Group Ginkophyta
3. Group Gnetophyte
4. Group Coniferophyta
Dominant plants on earth
Pollination results in double fertilization
Endosperm provides energy to developing embryo.
Xylem and Phloem
Dominant Sporophyte, reduced gametophyte
Megaspores and Microspores
Wind dispersed, and animal pollinated
Microstrobilous (male cone)
Megastobilous (female cone)
Pollinated by beetles
No flowers or fruit
Females produce sticky seeds
1. Subgroup Gnetum- tropical vines
2. Subgroup Welwitschia-survive on dew and fog
3. Subgroup Ephedra- scale like leaves, photosynthetic stems
Pollen tubes transport sperm to egg
Tallest and oldest group.
Pollinated by wind and fire
Pollination- When the pollen actually lands on the stigma.
Fertilization- When the pollen meets the egg and they fuse to form a zygote.(sperm nuclus meets egg nucleus)
Carpel consists of:
Ovary (becomes fruit)
The Stamen consists of:
1. Basal Angiosperm (oldest lineage)
3. Eudicot (Most important for our lab)
Efficient vascular systems
symbiotic association with fungi
Short generation times
variety of seed dispersal mechanisms
adaptation to encourage insect pollination
- increase the surface area of the plant body
- serve as the primary photosynthetic organ of vascular plants
1. Ground Tissue
2. Dermal Tissue
3. Vascular Tissue
1.Parenchyma- most common cell, and has intercellular spaces between cell walls.
2. Collenchyma- supportive tissue: Supports the younger parts of the plant
3. Sclerenchyma- supportive tissue: Supports the mature parts of the plants. Lignified cell walls stain red
1. Xylem- conduct water and minerals from root to plant
2. Phloem- moves photosynthetic product through the plant
1. Taproots- large primary root with small secondary roots (seen in eudicots)
2. Fibrous roots- Similar size in primary and secondary roots (seen in Monocots)
Diving cells, root elongation and primary growth.
Protected by root cap
Cells are produced here by mitosis.
They lengthen to zone of elongation
Develop in the zone of maturation
The bulk of the root;
Consists of ground tissues, which protect the vascular tissue at the center of the root
Form when multiple ovaries of a single flower aggregate or are scattered over the surface of a receptacle.
EX: Strawberries, Rasberries
Form when the ovaries or two or more flowers combine and produce a single mass.
One ovary forms one single flower.
Thickened ovary wall in simple fruits
1. Dehiscent- seed split open
2. Indehiscent- Seed not split open
1. Opposite- two leaves per node
2. Alternate- One leaf per node
3. Whorled- 3 or more leaves per node
1. Vascular Cambium
2. Cork Cambium
Lies between the xylem and phloem, and produces secondary xylem.
Results in annual growth rings
Attached directly to the stem by a sheath.
Parallel venation in the leaves.
Have a blade or petiole, which attaches to the stem at the nod.
Netted venation in the leaves.
Consists of specialized parenchyma that contains chloroplasts.
2. Radial Symmetry
3. Bilateral symmertry
Two layers of tissues:
2 Germ layers: endoderm and ectoderm
3 layers of tissues:
3 germ layers
e.g. most animals
A true coelom is _____.
a body cavity lined with mesoderm
1. Polyp- sessile
2. Medusa- Mobile
1. Class Hydrozoa
2. Class Scyphozoa
3. Class Cubozoa
4. Class Anthozoa
CORALS OR ANEMONES
1. Subphyla Cheliceriformes
2. Subphyla Myriapoda
3. Subphyla Hexapoda
4. Subphyla Crustacea
Scorpios, ticks, spiders
Lack antennae and mandibles
2 body regions: Cephalothorax & Abdomen
Centipedes and Millipedes
Single pair of antennae and three body parts
Two pairs of legs per segments
One pair of legs per segment
90% species are insects
Head, Thorax, Abdomen