Lectures 1-15 Flashcards
Why is it so hard to have a fossil record?
- fossilization is very rare
- Most organisms leave no trace
- Occasional preservation
- Seas and lakes - slow accumulation of sand and silt
What is algae?
A eukaryote, photosynthetic, and unicellular and multicellular
What is cyanobacteria?
prokaryote, photosynthetic, unicellular and multicellular
What is bacteria?
prokaryote, non-photosynthetic, unicellular
What is the timeline for first organisms on earth?
- 3.5 billion years ago (first prokaryotes)
- bya: first eukaryotes (single-celled)
- 1.2 bya: first multicellular eukaryotes
- 535-525 mya: cambrian explosion (lots of diversity)
- 500 mya: colonization of land by fungi, plants, and animals
What were the environment requirements for plants to conquer land?
- Formation of sizeable and stable near-shore
- development of soils
- Amelioration of atmosphere
- Suitable climatic conditions
What are challenges for organisms leaving water to go to land?
- Desiccation of the body tissues, requiring some sort of waterproof coating
- respiration of gaseous oxygen rather than oxygen dissolved in water
- Mechanical support (air is not as buoyant as water)
- reduce need for water for reproduction
What was the first vascular land plant (430-400 Ma)?
It is known as cooksonia, the oldest fossils are found in Ireland
what are the roles played by fungi?
- Decomposers (soils dont work without them)
- Mutualists (work with lichens)
- Parasites (different kinds are parasitic, zombie ant, ring worm)
What is the Fungal reproduction and life cycle like? (asexual)
- Haploid (n)
- Mycelium
- spore producing structures
- spores (n)
- germination
What is half the oxygen on earth generated by?
It id generated by algae through photosynthesis
What is a lichen?
unicellular or filamentous green algae or cyanobacteria living among the filaments (hyphae) of a fungus
What are bryophytes?
They are nonvascular plants, water transport through diffusion and osmosis
What is a vascular system in plants?
They have: a phloem, and a xylem
what is a seed?
A seed is an embryonic plant enclosed in protective outer covering
What are seed characteristics?
- seed contains tiny embryonic plant, a source of energy to fuel initial growth and protective coat
- seeds are able to disperse, allowing of dispersal throughout the world
- can be very long-lived and variable
What are gymnosperms?
They are naked seeds, ginkgo’s and conifers have them
- first appeared 360 million years ago
What are angiosperms?
Receptacle seeds, they first appeared 125 million years ago
What are the different ways to classify animals? order biggest to smallest -
- Domain
- Kingdom
- phyla
- class
- order
- family
- genus
- species
REMEMBER - Dear King Philip Came Over For Good Soup
What does Heterotrophic mean?
They obtain organic compounds by ingesting or absorbing them
What are tissues?
A group of cells with a common structure, function or both
What are the muscle and nerve tissues unique to animals?
- Connective tissue
- Epithelial tissue
- Muscle tissue
- Nervous tissue
What is a phylogeny?
A branching system showing how species are related to each other, the branch length is proportional to time and nodes show the ancestor of the group.
How are phylogenies constructed?
They are made by looking at the similarities and differences among species: physical and or genetic characteristics
What are the different body plans that animals are/where characterized by?
- Porifera (asymmetrical or radially symmetrical, body with wall pores)
- Cnidaria
- Ctenophora
- Ectoprocta
- Brachiopod
- Echinodermata
- Chordata
- Platyhelminthes
- Rotifera
- Mollusca
- Annelida
- Arthropoda
- Nematoda
What are Eumetazoa Porifera (also known as sponges)?
There are 5,500 species
- sessile (fixed in one place)
- Mostly marine
- lack true tissues
- clumps of cells held together by collagen
- suspension feeders
What is the difference between Radiata and Bilateria? (shape)
- Radiata is circular and can be cut in multiple places (think circular anemone)
- Bilateria can be cut in half (lobster is the example)
What are species considered to be Radiata?
Cnidaria: which include
- Sea anemones, corals, hydra and jellyfish
What are things to know about Radiata? (sea anemones, corals, hydra and jellyfish)
- 10,000 species
- Carnivores
- Feed using stinging cells called nematocysts
- Some are colonial (corals and Portuguese Man o’war)
What are species included in Deuterostomia- echinodermata?
Echinodermata - Starfish, sea urchins, sea lilies, and sea cucumbers
What to know about Deuterostomia- Echinodermata? (starfish, sea lilies, and sea cucumber)
- 7,000 species
- Marine
- Move and feed using a water vascular system and tube feet
- Bilateral symmetry as larvae but radial
What species are included in Deuterostomia - chordates?
Lancelets, hagfish, tunicates, vertebrates
To know about Deuterostomia - chordates? (lancelets, hagfish, tunicates, vertebrates)
- 52,000 species
- posses a notochord
- most are vertebrates
- contains most of the things we think of as animals - mammals, birds, fish, amphibians, reptiles, and humans
What are Lophotrochozoa - platyminthes?
They are flatworms
- 20,000 species
- no body cavity or organs for gas exchange
- includes tapeworms and trematodes (parasites)
What are Lophotrichozoa - annelida?
Segmented worms
- 16,500 species
- mainly aquatic
- two main groups - polychaetes (mostly marine) and oligochaetes
- include earthworms and leeches, very important to humans
What are Lophotrichozoa- Mollusca?
Gastropods, bivalves, cephalopods
- 93,000 species
- Often have shells
- Well developed eyes
- Cephalopods have particularly complex brains for invertebrates
What are Ecdysozoa-nematoda?
Roundworms
- 25,000 species
- very abundant in soil and freshwater
- covered in tough cuticle
- Many are parasites to plants and animals
What are Ecdysozoa- Arthropoda?
Crustaceans, insects, arachnids
- 1,000,000 species
- the majority of all identified species are arthropods
- segmented skeleton with joined limbs
- Important to humans as food, pests, disease vectors, and pollinators
Why was there such an increase in diversity in the Cambrian era?
- increased atmospheric oxygen allowed species to have higher metabolic rates to grow larger and complex
- The evolution of Hox genes, allowed developmental pathways to be used
- Increase in predator variety, drove selection for anti-predator defense
What are characteristics of chordates?
- Eumetazoa (true tissues)
- Bilaterally symmetrical
- Deuterostomes
- With a notochord
What are characteristics of Craniates?
- Chordates
- With a HEAD
- Hagfish example
What are characteristics of vertebrates?
- Chordates
- craniates
- With a backbone
- Lamprey included
What are characteristics of Gnathostomes?
- Chordates
- craniates
- vertebrates
- with jaws !!
What are characteristics of Osteichthyans?
- Chordates
- Craniates
- vertebrates
- Gnathostomes
- with lungs or swim bladders
What do you need to survive on land?
- Skeletal support
- Lungs (to breathe air)
- Limbs (to move)
- A neck (so you can move your head to catch food)
When did tetrapods move to land?
They moved to land sometime in the Devonian era (not quiet sure)
When was Romer’s gap?
very few fossils exist between 360 to 345 MYA, but after there are many tetrapod fossils
What are some aspects about humans that make them unique?
- Larynx lower in the throat, unattached hyoid bone, articulate words when speaking
- Bipedal
- Foramen magnum is beneath the skull so we hold our heads upright
- Spine has a lumbar curve hold our weight over our pelvis
- feet designed to bear weight not to grasp
- Humans have very large brains
- ## Sophisticated food gathering and processing techniques
What are the four major feeding strategies?
- Suspension/filter feeders
- Fluid feeders
- Substrate feeders
- Bulk feeders
How does suspension feeding work?
Suspension feeders use some kind of apparatus to filter food out of water or air
An example: Krill use a feeding basket made from their apendages
What are some examples of filter/suspension feeders?
- Manta rays
- Basking sharks
- Whale sharks
- Herring, sardines, anchovies
What do all sponges have in common?
They are all suspension feeders
How do spiders filter feed?
They filter insects from the air using their web
What are fluid feeders?
They suck nutrients from a living host (e.g. phloem, blood) - many are parasites, but others are also beneficial like pollinators.
What are some examples of fluid feeders?
- Leptonycteris bats, moths and butterflies, hummingbirds, honey possums, honey bees, mosquito, aphids
What do substrate feeders do?
They live on or in their food (e.g. maggots, caterpillars)
What are bulk feeders?
Eat relatively large pieces of food (e.g. humans, pythons are as well)
What are the different kind of specialized diets?
- Frugivores (fruit)
- Folivores (leaves)
- Granivores (seeds)
- Nectarivores (nectar)
- Palynivores (pollen)
- xylophages (wood)
- Grazers (grass, low vegetation, seagrass, algae,)
- Browsers (woody vegetation
What are the challenges an animal must overcome to be an herbivore?
- Overcome plant defenses
- physical
- chemical
- other - Acquire the plant material
- Digest it
What are some plant adaptations that help them avoid being eaten?
- Chemical compounds
- Spines and thorns
- Maybe bodyguards (ants??)
What are adaptations that herbivores have to deal with plants?
- Hardened lips and tongues
- Agility to avoid thorns
- Specialized teeth
- Most herbivores are arthropods, they have so soft parts so they can easily avoid thorns
How is digestion hard for herbivores?
Most of the energy in plant material is found in cellulose from the plant cell wall, animals do not posses enzymes that break down cellulose -microorganisms do
What are adaptations predators have for catching and eating prey?
- camouflage (sit and wait, energetically cheap)
- Lures (another version of sit and wait
- Venom - paralyze their prey
- Speed (fast over short distances)
- Strength and stamina
What are adaptations of prey?
- camouflage
- poison and warning colors (aposematism)
- living in groups
- mimicry (Batesian mimicry, butterflies)
- Mulleran mimicry
What is Intra-specific?
Within species
-group living
- competition (food, mates)
- reproduction
- sexual conflict
What is Inter-specific?
Among species
- Predation and herbivory
- competition (food, space)
- Mutualisms
- Parasitism and disease
- pollination
What is the purpose of reproduction?
To increase fitness
- to get as many genes into the next generation as possible
What are reproductive challenges?
- choosing and finding a mate
- ensuring fertilization success
- Ensuring offspring survive to reproduce
How do many marine species reproduce?
By releasing sperm and eggs into the water -
- External fertilization
- Often mass spawning
- energetically cheap
- could potentially have many offspring
- overwhelms predators
-NO mate choice
What are the different types of mating systems?
- Monogamy (most birds, humans)
- Polygyny (most insects and mammals, male has more than one mate)
- Polyandry (women have more than one partner, some birds, fish)
- Promiscuity (chimps, bonobos)
How does INTERsexual selection work?
- females choose
- monogamy and polygyny
How does INTRAsexual selection work?
- Males compete
- polygyny
How is sexual selection a form of natural selection?
Traits selected in natural selection are those that influence survival, they also directly influence meting success
What is INTERsexual selection?
section for traits that increase attractiveness to females e.g., colors
- Birds are a big example of this
What is INTRAsexual selection?
Selection for traits that increase success at fighting e.g. antlers
- males fight, ornaments to fight
What is the good gene hypothesis?
Trait used in display are energetically costly so they give the female an honest signal about how good the male is at acquiring food or resisting disease
- choosing a mate with “good genes” maximizes the females fitness
What is the sexy son hypothesis?
Traits used in fights or display will be passed on to the female’s sons, increasing the likelihood of mating in the future
- More likely to pass on to the next generation
Why do females invest more energy in offspring than males?
- Eggs are bigger then sperm
- Incubating eggs
- Internal development of young
- Parental care is generally the role of the mother
- In mammals females produce milk
How do males and females maximize their fitness in different ways?
Males: best way to ensure to have genes in the next generation is to have as many offspring as possible and hope some survive
Females: the best way to ensure that their genes are passed on is to have few, high quality offspring
What is Intersexual conflict?
Drosophila males use chemicals that kill the sperm of other males, but can also damage the females
- Ducks
What are the pros and cons of Asexual reproduction plants?
Pros:
- No mate required
- Rapid & saves energy
- Adapted to current environment
Cons:
- Low genetic variability
- Adaptation difficult
- Slows evolution
What are the pros and cons of sexual reproduction?
Pros:
- high genetic variability
- facilitates adaptation
- facilitates evolution
Cons:
- Mate requires
- Energy costly
- Slower than asexual
What percent of species have gone extinct?
99% of species have gone extinct
What is an example of poor design in evolution?
The vertebrate eye - the light comes in through all the “wiring” not from the side where the receptor cells are.
What did Carl Linnaeus do?
Described thousands of species and named them using descriptive 2-part names, for genus and species
- hierarchical phylogeny using 7 levels
Who was Erasmus Darwin?
Grandfather to Charles Darwin
Ideas foreshadowing evolution:
- common descent
- heritability
- survival of the fittest
- struggle for existence
What is gradualism?
Small apparently weak forces (e.g. small rivers) could given enough time have huge geographical effects
What is Uniformitarianism?
All geological processes ever existing are still going on
What was the Beagle voyage?
(Dec 1831 -Oct 1836)
When Darwin was 22 he became the naturalist on the voyage, observed and collected specimens, plants, animals, rocks, and fossils
What were Darwin and Wallace’s insights?
- Horizontal speciation
- Gradualism
- Common descent
- Man as an animal
- Natural selection
What is Horizontal speciation?
Darwin observed 2 species of rhea, and realized they could have BOTH evolved from the same ancestor (split evolutionary line)
What is the concept of gradualism?
speciation happened gradually and was not sudden
When is Natural selection inevitable?
- Replication
- Variation between individuals
- Heritability of traits
- Differential survival
What is the pangenesis theory -proposed by Darwin?
it said that variations acquired during the animals lifetime are transmitted to the germ cells, returning variation to the system (theory is incorrect)
What did Mendel’s genetics show us?
- Inheritance through alleles of genes is particulate not blended (offspring get the full trait from one or other parent
- maintains variation - Acquired characters are not inherited, so play no part in evolutionary change
What is punctuated equilibrium?
new species are formed by leaps called “hopeful monsters” where whole organisms changes occur. But anything surviving this is very small.
What is our current thought on what happens evolutionarily?
Punctuated Gradualism-
faster change when selection pressure is high and variation is present. Slower or no change (stasis) when less selection pressure or mutations ae needed
What are the 3 types of selection over geological time scales:
- One extreme of the population is the fittest, which gives DIRECTIONAL selection (the bigger the better)
- The mean of the population is the fittest it is STABLAIZING selection
- if both extremes are fitter than the mean or the middle is disadvantageous then it is DISRUPTIVE selection
How do organisms maximize their fitness?
- Looking after their own interests
- fighting for mating opportunities
- having as many offspring as possible
- competing for food
- helping their relatives not their rivals
What are things that are important to consider when thinking about evolution?
1.it is not about the individual, trying to survive or breed, its a race between different versions of the same gene
2. Animals are in competition with other of their species
What are concepts about natural selection?
- natural selection only selects within the available variation population
- Natural selection cannot plan ahead it only responds to current conditions
- Natural selection is between individuals but evolution happens to populations. individuals cannot change their genes
- there no intent , direction or purpose to evolution
What is the definition of a species?
It describes a group of individuals sharing a common gene pool, those who share the same gene pool cannot diverge from each other
What are the 5 main ways scientists have defined species?
- Biological species concept
- Evolutionary species concept
- Recognition species concept
- Morphological species concept
- genetic difference
What is the Biological species concept? (or isolation species concept)
If two populations become separated so they do not breed together, for instance one becomes isolated on an island
- they will stop interbreeding so their gene pools no longer mix
- Over time become too different
What are the weaknesses for the biological species concepts
Weaknesses:
1. Definition should specify that the young need to be fertile (zebroid, liger, mule)
2. Inappropriate for asexual organisms
3. too difficult to apply to fossils
4. Species isolated on island are problematic bc they would never get a chance to show that they could breed
5. organisms that just release gametes are problematic
What is the Evolutionary species concept?
A group of organisms that shares an ancestor; a lineage that maintains its integrity with respect to other lineages through both time and space, may or may not recognize subspecies and sister-species only when they have become distinct enough to clearly be different
Weakness: we usually like to know about sister species
What is the recognition species concept?
Species are separated by differences in their fertilization system (complex of behaviors and morphology, physiology, and biochemical features)
BUT:
- does not cater for asexual organisms
- how different is too different to allow mating
What is the Morphological species concept?
Used in difficult cases based on visible differences between species, taxonomists look for discontinuities in morphological variation
Problems:
- Polymorphisms
- Sexual dimorphism
- cryptic diversity
- Use of genetic markers (genetic markers and morphological do not agree)
How do you find differences in genetics between animals?
You look at the same gene and compare the number of differences in bases within that gene, they are called barcoding genes
What is integrative taxonomy?
Using several lines of evidence together to make a case to the taxonomists community, there is also a scoring system, scores 5 and above considered a species
What is Allopatric speciation?
Some form of barrier splits the population, or part of the population gets stranded on an island, the different conditions cause slightly different selection so they diverge.
Why do isolated populations change?
- Founder effect
- genetic drift
- natural selection in conditions different from those experienced by the founder population
What is the founder effect?
The rarest alleles are usually absent, but if the rarest allele is present then it will be much more common (the founder effect means the mixture of alleles is different in the new population that in the parent population)
What is genetic drift?
The effect of chance events on tiny populations, gene pool of small isolated populations becomes more different from that of the parent population due to chance events.
What is parapatric speciation?
Speciation at a border which does not prevent gene flow entirely
e.g. species of crickets int he Pyrenees interbreed only at the tops of certain mountains
When does the Hybrid zone widen or narrow?
Narrows: if hybrid offspring are less fit than the pure breeds of each type
Widens: if they are equally fit with pure bred offspring
What is sympatric speciation?
Requires isolation of a subset of the population within the original population, interbreeding must stop if two separate species are to form.
What is mutualism?
everybody benefits from a change in either species
What is Co-evolution?
when changes in one species cause adaptation in another, which further change the selective pressures on the first altering its evolution, and so on
How does Aposematism work?
The predator needs to know the meaning of the signal already. it also has to remember what signal means that it is poisonous
How do aposematic prey aid their predators to learn what their signal means?
- Conspicuousness
- Novel signal
- Repeated signal
- Consistent effect follows signal
- Effect follows signal quickly
- Confirmed by other signals
Mullerian Mimicry example:
Viceroy butterfly and models, they look really similar to monarchs that are very toxic
What is Batesian mimicry?
Completely harmless but resembles a defended model, mimics the confuse message, they are edible and teach the wrong message to predators, loose out re-educating the predator.
- predator looses out because they eat more toxic prey
What is an automimic?
a member of a aposematic species which lacks the defensive chemical so are effectively Batesian mimics of their own species (degrading their own signal!)
What does it mean to be polymorphic?
Allows a species to spread their load between more than one signal
example: 2 spot ladybirds have both red and black morphs so they can be apart of both red and black mimicry rings
What are the two problems with sex?
- How sexual reproduction could evolve in the first place
- How such mal-adaptively showy males could evolve
Difference between the amount of genes in asexual and sexual reproduction?
Sexual reproduction gives 50% of father genes and 50% mother
Asexual reproduction - each offspring has 100% of the mothers genes
Why is sexual reproduction less efficient?
- Only half of the individuals genes are present in each offspring
- Only half of the population is really breeding as males don’t produce offspring directly
What are other costs of sexual reproduction?
- finding a mate of the right species, age, sexual state is not always easy
- courtship and mating takes time, energy and is dangerous
- courtship is showy so attracts predators, and takes lots of time
- letting another individual that close carries dangers of parasites and diseases as well as physical injury
What are advantages of sexual reproduction?
More variation of offspring
- reduced sibling competition
- better protection against parasites
What is Muller’s Ratchet?
Gradual accumulation of deleterious mutations
When does asexual reproduction work and when does sexual reproduction work?
- Asexual reproduction works best when the environment is stable.
- Sexual reproduction will do well when the environment may change/slightly unstable
What is the Hill-Robertson effect?
Getting multiple mutations into one individual is easier when they are sexually reproducing
What are the two types of sexual selection?
Female choice = inter-sexual selection
- female selects her mate on some criterion she prefers
- leads to showy males
Male-Male competition = intra-sexual selection
- males compete for access to females
- leads to weapons such as antlers and tusks
Why do animals co-operate?
- Humans are weird
- Reciprocal altruism
- Kin selection
- Forced co-operation
- Mutualism
What is alturism?
When the action is costly to the actor’s fitness, pattern of performed behavior that decreases the individuals fitness.
What is Mutualism?
Co-operation to obtain an end which one individual could not achieve alone so benefits both
- can be between or within species
