Exam 3 Flashcards
What are hybrid zones? Why are many hybrid zones narrow in width?
These are areas where two species come into contact and breed with one another
Usually narrow because of the possible outcomes of:
-REINFORCEMENT: selection to prevent hybrid formation
-FUSION: species fuse back into one species
-STABILITY: hybrids continue to form, don’t leave narrow zone
What is the difference between gradualism and punctuated equilibrium?
Gradualism: a process of evolution that suggests that changes occur slowly and constantly over time.
Punctuated Equilibrium: a process of evolution that suggests very short, rapid periods of change followed by long periods of stability.
Provide an example of gradualism and an example of punctuated equilibrium.
Gradualism: finches, whales
Punctuated Equilibrium: Cambrian explosion
Put the following groups of organisms in sequence from oldest to most recent, in terms
of their first appearance in the fossil record:
mammals, invertebrates, prokaryotes, land plants, algae
Prokaryotes
Algae
Land Plants
Invertebrates
Mammals
Given the age of the Earth, have humans been present for much of it? What about other animals?
NO - humans have only appeared around 200,000 years ago
Other animals first appeared 600 MILLION years ago
Why is it important to understand continental drift when studying evolution?
This is because it can lead to vicariance, which is when a natural situation arises to physically divide organisms.
Is continental drift still occurring?
YES - N. America and Europe drift apart about 2cm each year!
List two conditions or events that can lead to adaptive radiation. For each condition explain how the condition could lead to adaptive radiation. Provide examples.
Extinction - surviving organisms, say in the extinction of dinosaurs, have new environmental opportunities as the niches are “empty”
Geographic Isolation - dispersals to new areas, like Hawaiian Silverswords, has allowed for them to radiate into new species dependent on these new environments
When was the adaptive radiation of the mammals? Why? Was this adaptive radiation the first time mammals were present on Earth?
The adaptive radiation of mammals was AFTER THE EXTINCTION OF DINOSAURS - this led to empty niches for which surviving organisms could survive
Not the first time mammals were present, but there were much fewer before then
TRUE/FALSE: More than half of the species on Earth have been described/named.
FALSE - only about 2M have been described
It is estimated that there are 5 - 30 million species yet to be discovered
Which of the extinctions, the Permian or Cretaceous, is the oldest?
Permian
According to the geological evidence, which event may have triggered the Permian mass extinction?
global warming caused by massive volcanic eruptions
-release of greenhouse gases leads to warming
According to the geological evidence, which event may have triggered the Cretaceous mass extinction?
combination of volcanic eruptions and asteroid
Mass extinctions are often followed by ______________.
Increase in diversity
Define Systematics
Study of the diversity of life
What is taxonomy and why is it important?
Name and Classification of Species
important in categorizing and organizing to better communicate species
Which classification is more broad: Phylum or Family?
Phylum
KPCOFGS
What is phylogeny?
What type of data is used to construct phylogenies?
What does a phylogeny tell us?
Evolutionary hypothesis of a group of organisms
morphological/molecular homologies
shows a pictorial representation of evolutionary history and common ancestry
TRUE/FALSE: Evolutionary patterns convey a goal of evolution
FALSE - evolutionary patterns do NOT convey a goal of evolution (it shows a common ancestor)
What is the difference between a derived characteristic and an ancestral characteristic?
Derived = new traits unique to a lineage
Ancestral = characteristic that was present in the common ancestor/ancestral group
Where is the common ancestor to all of the organisms noted in the phylogenies?
at the Root
What does a Node represent on a phylogeny tree?
Speciation Event / Common Ancestor
TRUE/FALSE: No extant species are more “primitive” or “advanced” than others
TRUE - these have evolved for an equal amount of time
What is a Clade in phylogeny trees?
group of organisms containing the COMMON ANCESTOR and ALL OF ITS DESCENDANTS
How do Cladogram, Phylograms, and Chronograms differ?
Cladogram = depicts relationships (BRANCH LENGTHS ARE NOT INFORMATIVE)
Phylogram = branch lengths are PROPORTIONAL to AMOUNT OF CHANGE
Chronogram = branch lengths are EXPLICITLY PROPORTIONAL TO TIME
Why is the streamlined body plan of penguins, seals, and sharks considered an analogous trait and not a homologous trait?
While they serve the same purpose (propulsion in water), they don’t have the same ancestral structural origin and evolved independently
Streamlined shape in whales and dolphins are ____________.
homologous
Streamlined shape in penguins, seals, and sharks are _________________.
analogous
What are some of the reasons we use phylogenies?
- Taxonomy/classification of biodiversity
- Trait Evolution
- Biogeographic patterns/distribution of biodiversity
- Understanding invasion biology
- Track disease agents
- Solve crimes
- Prioritize conservation decisions
- Date evolutionary events
Milk production by mammals when compared to other vertebrates is an example of a ________________.
shared derived character
When building a phylogenic tree, what does it mean when trying to achieve the most PARSIMONIOUS tree?
tree with the FEWEST number of trait changes
TRUE/FALSE: Animals are more evolved than plants, fungi, protists, bacteria, and archaea
FALSE - all extant organisms are EQUALLY evolved
How does animal heterotrophy differ from fungi?
Fungi absorb their food, animals engulf their food
What are the Three Characteristics of Animals?
- Nutritional Mode (injest food; enzymes to digest food WITHIN the body)
- Cell Structure and Specialization (multicellular eukaryotes)
-LACK cell walls
-structural proteins to stabilize cells
-specialized cell types (muscle, nerves) - Reproduction and Development
-most reproduce sexually
-some asexually
-some both
In what two ways do Animals develop?
- Develop from immature form (humans, leopard, dolphin)
- Develop from larval stages via METAMORPHOSIS (butterflies)
What are the four components of Body Plans?
- Symmetry
- Tissues
- Body Cavities
- Protostome or Deuterostome
What is Radial Symmetry? What lifestyle has this symmetry?
HAS top and bottom
NO left or right; front or back
LIFESTYLE:
-often sessile or planktonic (drifting)
-same/similar function on all sides
e.g., anemones, jellies
What is Bilateral Symmetry? What lifestyle has this symmetry?
Top (dorsal) and Bottom (ventral)
Left and Right
Front (anterior) and Back (posterior)
LIFESTYLE:
-Central Nervous System controls complex active movements
Which animal lacks tissues?
Porifera (sponges)
What are the 3 Germ Layers?
- Ectoderm = outer layer forms outer layer and CNS
- Endoderm = innermost later forms lining of digestive tract, liver, and lungs
- Mesoderm = only in bilaterally symmetrical organisms; found between the endo and ecto; forms muscles and most organs
What is a Body Cavity?
fluid or air-filled space between digestive tract and outer body wall
What is the Coelom of body cavities, and their functions?
“hollow” area
-suspension structure for organ attachment
-cushions organs
-allows independent movement and growth of organs
There are two early-stage developmental modes.
What are they and how are they defined?
- Protostome = “first mouth”
-mouth develops first, then anus - Deuterostome = “second mouth”
-anus forms first, then mouth
What mode of development are humans?
Deuterostome
What would you predict animals with a radially symmetric body plan can do better than animals with a bilaterally symmetric body plan?
deal effectively with food distribution homogenously in 360 degrees
95% of all known animal species are ___________
invertebrates
What are some characteristics of Porifera (sponges)?
-LACK true tissue layers
-Sessile suspension feeders
When compared to Porifera (sponges), how is the Eumetazoa branch different? What are some examples?
have TRUE TISSUES, which Porifera LACK
This includes all animals EXCEPT for sponges
e.g., jellies, anemones, corals
Within Bilateria, what is unique about this branch? When did they occur?
BILATERAL SYMMETRY
-vast majority of extant animals
-diversified during the Cambrian explosion
What possibly caused Bilateria?
-increase in ocean oxygen from photosynthesis
-prior major extinction events (which led to newly available niches)
-new coevolutionary dynamics from new body forms (hard parts, new feeding niches)
What do changes in Hox gene expression lead to?
body plan innovation!
What is the most PRESENT period of evolution?
Phanerozoic Eon
-evolution of diverse plant and animal lineages
-only 100my after Edicaran
What did the Cambrian Explosion show?
evolution of hard body parts
-likely for protection against predation
TRUE/FALSE: Only a fraction of Ediacaran fauna share traits with existing lineages
TRUE - almost all extinct within 40 million years
The Cambrian Explosion was an exciting time for animal body plan innovation.
What genetic changes are thought to have contributed to the diversification of arthropod body plans during this time?
Changes in regulation of Hox genes
As part of Bilateria, what are the Lophotrochozoa and examples?
-Very Diverse Body Plans
- Platyhelminthes
- Annelida
- Mollusca (squid, slugs, snails, clams, oysters)
As part of Bilateria, what are the Ecysozoa and examples?
-shed tough cuticle coat during growth…ecdysis (molting)
- Nematoda - most abundant!
- Arthropods - most abundant!
- Crustacea
- Myriapoda
- Oncophora
- Hemiptera
What is Ecdysis, or molting?
shed tough cuticle coat during growth
An arthropod is considered to be cosmopolitan. What does this mean?
found nearly everywhere on earth
What are some characteristics of Arthropods?
-cosmopolitan
-open circulatory system (hemolymph bathes organs)
-ventral, solid nerve cord
-hard exoskeleton (protection and desiccation resistance)
What are the most diverse Arthropods?
Insects!
-live in all habitats
-wings are modified cuticles
-metamorphosis in many species
Which of the following is NOT one of the three major lineages of living Ecdysozoa:
Chelicerata
Myriapoda
Nematoda
Mollusca
Mollusca - it is a Lophotrochozoa
As part of Deuterostomes, there are Echinoderms. What are their characteristics and examples?
-“spiny skin”
-slow-moving or sessile
-some are radially symmetric
-water vascular system
e.g., sea stars, sea urchins
As part of Deuterostomes, there are Chordates. What are some examples?
-lancelets
-tunicates
-hagfishes
-vertebrates
What are the 4 unifying characteristics of Chordates?
- Notochord - strong, flexible fluid-filled rod, gives rigidity to the body and allows muscles to move against it, degenerates by adulthood in many species but is present in embryos
- Dorsal, Hollow Nerve Cord - develops into CNS
- Pharyngeal Slits or Clefts - develop into gills of fish; parts of ears, head, and neck in tetrapods
- Muscular, Post-Anal Tail - movement in aquatic species, balance in terrestrial species, reduced in some, including humans -> coccyx
Which of the following is not a major clade of bilaterian animals:
Eumetazoa
Lophotrochazoa
Ecdysozoa
Deuterotomia
Eumetazoa
What are the characteristics of the Subphylum Vertebrata, of Chordates?
-distinct head
-vertebrae of bone or cartilage; cranium
-pharyngeal arches
-endoskeleton of bone or cartilage
-heart with 2-4 chambers
-coelom (body cavity) well developed with organ systems
-nearly always separate sexes
Why do human embryos develop like fish?
Common ancestry!
What does Paedomorphosis refer to?
retention of juvenile features
What is one of the MAJOR KEY INNOVATIONS in vertebrate evolution
Jaws!
-mandibular arch evolved into biting structures of jaw
-hyoid arch evolved into jaw support structures
-the gill arch genes that formed these were from Hox genes!
What makes Bony Fish (Osteichthyes) a dominant group of fishes?
-thin, lightweight scales
-fins highly maneuverable
-ossified vertebrae
-premaxilla and maxilla moveable
-swimbladder (takes in air to float - hydrostatic function)
-lateral line system
Molecular and developmental evidence indicate that ____________ evolved from lungs.
gas bladders
Fish can detect changes in surrounding water movement via ______________
lateral line organs
-sound
-vibration
What is the purpose of otoliths within the capula?
helps to determine balance and change in surroundings with the flow of a liquid across the capula
What colonized terrestrial environments first?
Prokaryotes
What is the “Law of Succession?”
extinct fossil species typically succeeded (same region) by similar species
What are some characteristics of Tetrapods?
-legs support weight on land and digits receive weight transfer
-“Neck” - atlas/axis
-pelvic girdle fused to backbone
What are examples of Tetrapods?
amphibians, reptiles, mammals
What is Tiktaalik and its importance?
-illuminates steps in tetrapod evolution
-transitional link between earlier and later forms
-broad skull
-flexible necks
-eyes on top (peek above water to look for prey)
-primitive wrist
-5 digits
Where did Tiktaalik most likely live?
near warm shallow waters
What is the Hedgehog gene?
gene made one end look different from the other (first seen in fruit flies, then seen in chickens)
-every limbed animal has the sonic hedgehog gene
What are Hox Genes?
“Master switch genes”
-highly conserved across multicellular animals
-affect anterior to posterior position of structures in developing embryo body
MAP OF THE BODY PLAN
What helps create new body plans?
Mutations!
What are 3 key characteristics that animals have?
- NUTRITIONAL MODE: They are heterotrophs (ingest food and digest it via enzymes within the body
- CELL STRUCTURE & SPECIALIZATION: multicellular eukaryotes, lacking cells walls; use structural proteins to stabilize the cells (collagen)
- REPRODUCTION & DEVELOPMENT: most reproduce sexually, other asexually and some both
What are the ways that animals and other eukaryotes are different?
Specialized cell types and functions DIFFERENTIATE animals from other eukaryotes
e.g., muscle, nerves
What are the ways that animals and fungi are similar?
Both are eukaryotic and heterotrophic
What is the closest relative to animals? Was the ancestor of this organism and animals unicellular or multicellular?
choanoflagellates = common ancestor to ALL animals
unicellular
What are the two specialized cell types in animals?
muscles cells and nerves
What is Metamorphosis? Provide two examples of animals that undergo Metamorphosis during their lifetime
a multi-step developmental transformation of an organism from larval stages into an adult form
e.g., butterflies, frogs
Describe reproduction and development in animals
- Performed mostly sexually (but can also be asexually, or both, in some animals)
- A flagellated sperm fertilizes an egg - forming the zygote
- Rapid cellular division, or cleavage, occurs until a Blastula, a hollow ball of cells, is formed
- Gastrulation occurs in the Blastula, leaving an in-folding of cells to create a multilayer structure - this is now called the Gastrula
How is animal reproduction similar to the reproduction of plants? How do they differ?
SIMILAR:
-male and female gamete
-reproduce sexually
DIFFER:
-plants undergo both mitosis and meiosis, animals just under meiosis
-eggs in animals differ in form than ovule of plant
Provide examples of animals with RADIAL symmetry and animals with BILATERAL symmetry
RADIAL:
-anemones
-jellies
-sea stars
BILATERAL:
-humans
-crab
-butterfly
What are the 3 germ layers and what do these each become?
- Ectoderm - becomes the CNS
- Endoderm - becomes the digestive tract, liver, and lungs
- Mesoderm - becomes muscles and most organs (only found in bilaterally symmetrical organisms)
What is a coelom and what are some of its functions?
Coelom = fluid or air-filled space between digestive tract and outer body wall
-suspension structure for organ attachment
-cushions organs
-allows independent movement and growth of organs
What is the difference between a Protostome and a Deuterostome?
Protostome (“first mouth”) is the developmental mode where the mouth forms first, then the anus
Deuterostome (“second mouth”) is the developmental mode where the anus forms first then the mouth
What is a key characteristic of invertebrates? Name an example.
NO BACKBONE
e.g., anemones, jellies, corals, Mollusca
Are humans part of the group Eumetazoa? What is a derived trait for organisms that are in Eumetazoa?
Yes - this is because of the derived trait of “true tissues”
Is Eumetazoa considered monophyletic, paraphyletic, or polyphyletic?
Monophyletic
What is hemolymph? What type of organisms have this?
a fluid, similar to blood, in invertebrates that bathes their organs as part of their “open” circulatory systems
-found in invertebrates
Provide an example of the coevolution of insects with angiosperms.
Coevolution is when two or more species that interact with each other regularly evolve in response to each other’s adaptations
through cross-pollination, angiosperms may adapt to a larger/smaller size to attract and be able to withstand insects without damage
insects, in turn, can adapt to have longer/shorter proboscis dependent on the angiosperm flower
Is a chordate always a vertebrate? Why why not? Is a vertebrate always a chordate?
NO - cephalochordates (lancelet) and urochordates (tunicates) contain a notochord (skeletal rod) while vertebrates contain a vertebral column not seen in the other two
Vertebrates are ALWAYS a chordate though, as they first contain a notochord during development that transitions into a vertebral column
What is the difference between a species that is Endothermic vs Ectothermic?
Endothermic = can internally regulate temperature
Ectothermic = rely on outside environment to regulate temperature
What is Amnion and its function? What types of animals have Amnion?
Amnion = fluid that supports the embryo (via eggs, liberated from water)
e.g., reptiles, birds, mammals
How are amphibians and reptiles similar? Different?
SIMILAR:
-ectothermic
-double circulation
-keratinized epidermis
DIFFERENT:
-reptiles have amniotic eggs, amphibians have delicate, jelly-coated eggs (in water) - NO LARVAL STAGE
-reptiles not dependent on aquatic habitats for reproduction
-amphibians are metamorphic
How do mammals differ from other animals? List 3
- Mammary Glands - production of milk to feed offspring
- Have Hair/Fur
- Are Warm-Blooded
- Sweat Glands
- Diaphragm
- Differentiated Teeth
What are Hox genes and what do they do?
genes that encode transcription factors and are essential during embryonic development
-MAP the body plan
-changes to Hox gene expression lead to BODY PLAN INNOVATION!
What 4 characteristics do ALL chordates have some time during their development?
- Notochord
- Dorsal, hollow nerve cord
- Pharyngeal slits
- Muscular, post-anal tail
What are temporal openings and what do they achieve?
How many temporal opening are in:
1. Anapsids
2. Synapsids
3. Diapsids
openings on the skull that PERMIT WIDER GAPE by allowing more attachment sites for jaw musculature
Anapsids = 0 (e.g., most turtles)
Synapsids = 1 (e.g., mammals, some turtles)
Diapsids = 2 (e.g., lizards, snakes, crocodiles, birds)
In comparison to fish, what type of circulation do mammals have?
Double circulation
-fish have single circulation
What are some modifications for flight in birds?
-feathers
-hollow bones
-reduced forearm bones
-sternum with keel
Who are the most recent common ancestors of birds?
dinosaurs (~150mya)
Which extant species is most closely related to humans?
Chimpanzee and Bonobo
TRUE/FALSE: Feathers evolved with birds.
FALSE - they evolved long before birds with a group of Theropod Dinosaurs
How do marsupial and eutherian mammals differ?
Marsupials = pouch (embryo does not plant in the uterus)
Eutherian mammals = placenta
Euth > Gestation (smaller in Marsupials)
Mars. Longer lactation (less in Euth.)
How do monotremes differ from other mammals? Provide an example of a monotreme.
Monotremes = egg-laying mammals
-milk oozes out of specialized sebaceous (sweat) glands
-eggs incubate for a short time
-have a urogenital opening called cloaca
e.g., platypus
A sugar glider is a marsupial while a flying squirrel is a placental mammal. Both types of mammals have extra skin connecting their forelimbs and hindlimbs, allowing the animals to “glide” when they jump from branch to branch in a tree.
Is this extra skin an analogous trait or a homologous trait?
An example of divergent evolution or convergent evolution?
Analogous Trait
Convergent Evolution
What are the characteristics of primates?
-opposable thumbs
-developed brains
-sociality
What are ways in which humans differ from their closest extant relative?
Adaptions to RUNNING!
-longer legs
-arched feet
-can beat a horse in a longer-distance run
Preserving food
Likely, did mammals evolve from anapsids, synapsids, or diapsids?
Synapsids - 1 temporal opening
What is the Intermediate between reptiles and mammals?
Cynodonts
The genomes of humans and chimpanzees are 99% identical.
What makes us different?
~19 regulatory genes differ in expression (mutations in expression)
changes in climate (cooler and drier) decreased forest area and promoted expansion into these grasslands, with novel food resources
Cultural evolution can lead to mismatch diseases (poorly adapted) in modern humans.
Give an example of this.
-crowding of teeth
-impacted wisdom teeth
-dental caries/cavities
