Animal Evolution and Behaviour (Term 1) Flashcards
What is the feature that best describes the structure of valid taxonomic groups?
Valid taxonomic groups correspond to monophyletic groups on the best estimate phylogeny.
The relation of an ancestrally pentadactyl limb in birds and whales is best described as an example of which one phenomenon?
Homology
The ctenophores first hypothesis is best described by which statement?
Despite morphological evidence that sponges are the most basal living animal phylum, the unusual genome of comb jellies has led some researchers to suggest they evolved before sponges.
Which feature of a mechanosensory neuron usually contains calcium channels and ligand-gated channels?
The synaptic junction.
Which of these experiments would tell you if a behaviour is learned or genetically decoded?
Perform a cross-fostering experiment where young wolves are raised by more or less aggressive parents.
Which of the following is a potential disadvantage of living in a group?
Increased likelihood of brood parasitism.
Which of the following is a definition of interference competition?
One species disrupts the foraging activity of the other.
What does R0 represent is parasitism?
The net production of new infected hosts by each infected host.
Aggregative response refers to…
The movement response of predators to prey density.
Of the following species which would best represent an animal with a ‘k’ life history strategy?
Gorilla
What is hierarchical classification in biology?
Taxonomy is a system of hierarchical classification in biology. This system classifies organisms into the categories of kingdom, phylum, class, order, family, genus, and species based on similarities and differences between them and other organisms. This system is hierarchical because each successive category has multiple categories within it. That is, two organisms can have the same class but belong to different orders, but all organisms of the same order all have the same class.
What characteristics are used to reconstruct animal phylogeny?
Phylogenetic trees are constructed using various data derived from studies on homologous traits, analagous traits, and molecular evidence that can be used to establish relationships using polymeric molecules ( DNA, RNA, and proteins ).
What are homologies and analogies?
Homologous structures share a similar embryonic origin; analogous organs have a similar function. For example, the bones in the front flipper of a whale are homologous to the bones in the human arm. These structures are not analogous. The wings of a butterfly and the wings of a bird are analogous but not homologous.
Phylogeny of Animals
The study of phylogeny (the branching sequence of evolution) aims to determine the evolutionary relationships between phyla. Currently, most biologists divide the animal kingdom into 35 to 40 phyla. Scientists develop phylogenetic trees, which serve as hypotheses about which species have evolved from which ancestors.
What are the 3 germ layers and what do they become?
The three germ layers are the endoderm, the ectoderm, and the mesoderm. Cells in each germ layer differentiate into tissues and embryonic organs. The ectoderm gives rise to the nervous system and the epidermis, among other tissues. The mesoderm gives rise to the muscle cells and connective tissue in the body.
what is a non bilaterian.
The non-bilaterian animals comprise organisms in the phyla Porifera, Cnidaria, Ctenophora and Placozoa. These early-diverging phyla are pivotal to understanding the evolution of bilaterian animals.
What is an animal?
Animals are classified within the animal Kingdom Animalia (a.k.a. Metazoa).
Animals are multicellular eukaryotes, with bodies that are made up of multiple cells.
(Some) animals have tissues that develop from embryonic layers.
Animals are heterotrophic (like other opisthokonts), meaning that they eat organic carbon, rather that being able to produce their own food by photosynthesis, in autotrophy as plants do for example.
Most animals are mobile.
There are exceptions to nearly every criterion for distinguishing animals from other life-forms (e.g. some animals are sessile).
Because animals are diverse, some are simple and some have become more complex and some have secondarily reduced complexity.
What are the four taxonomic classes of sponges.
Four taxonomic classes of sponges, distinguished mainly by spicule types:
Calcarea: spicules of calcium carbonate (CaCO3).
The only group with calcareous spicules.
Only group showing the 3 levels of organization (asconoid, syconoid and leuconoid), the others are all leuconoid.
Hexactinellida: glass sponges, spicules of silica (SiO2).
Demospongiae: just a skeleton of the protein spongin, or also spicules of the mineral silica.
Homoscleromorpha: same spicules as Demospongiae, but a different clade defined by molecular data.
Symmetry and development of bilaterian animals
The Bilateria /baɪləˈtɪəriə/ or bilaterians are animals with bilateral symmetry as an embryo, i.e. having a left and a right side that are mirror images of each other. This also means they have a head and a tail (anterior-posterior axis) as well as a belly and a back (ventral-dorsal axis).
What is protostomes in biology?
Protostomes are a clade of animals that undergo protostomy during their embryonic development. The protostomes, together with the Deuterostomes and the Xenacoelomorpha, make up a major group of animals called the Bilateria. These are triploblast animals that display bilateral symmetry.
What are the two groups of protostomes?
The protostomes can be divided into two major clades—the lophotrochozoans (including bryozoans, annelids, and mollusks) and the ecdysozoans (including nematodes and arthropods)—largely on the basis of DNA sequence analysis.
Definition of deuterostome
any of a major division (Deuterostomia) of the animal kingdom that includes the bilaterally symmetrical animals (such as the chordates) with indeterminate cleavage and a mouth that does not arise from the blastopore.
Characteristics of Echinodermata
They have a star-like appearance and are spherical or elongated. They are exclusively marine animals. The organisms are spiny-skinned. They exhibit organ system level of organization.
What defines the phylum chordate?
The phylum Chordata consists of animals with a flexible rod supporting their dorsal or back sides. The phylum name derives from the Greek root word chord- meaning string. Most species within the phylum Chordata are vertebrates, or animals with backbones (subphylum Vertebrata).
What are vertebrates?
Vertebrates are animals that have a backbone inside their body. The major groups include fish, amphibians, reptiles, birds and mammals. Invertebrates don’t have a backbone. They either have a soft body, like worms and jellyfish, or a hard outer casing covering their body, like spiders and crabs.
What is the Cambrian explosion?
The Cambrian explosion happened more than 500 million years ago. It was when most of the major animal groups started to appear in the fossil record, a time of rapid expansion of different forms of life on Earth
links between evolution, behaviour and ecology.
According to evolutionary psychologists, patterns of behavior have evolved through natural selection, in the same way that physical characteristics have evolved. Because of natural selection, adaptive behaviors, or behaviors that increase reproductive success, are kept and passed on from one generation to the next. Organisms evolve because they are in an ecological relationship with other organisms of their environment, and because the environment itself influences their evolution via natural selection.
What was Darwin’s concept of evolution?
Descent with modification, crucially including adaptation to the environment due to natural selection on heritable variation.
feedbacks between ecology and evolution
Evolution can operate rapidly, over generational timescales, at the same timescale in which ecological interactions occur (between biological individuals and with their environment).
(Evolution can also operate and have effects over very long timescales E.g. in macroevolution.)
Therefore, because evolution and ecology can operate on the same timescale, ecology could affect evolution and evolution could affect ecology.
Interactions in both directions, between ecology and evolution (and vice versa), may occur in feedback loops.
The Modern Synthesis (A.K.A. The New synthesis)
In the mid 20th century new insights into the mechanism of genetic inheritance (based on genes) allowed the integration of Darwinian ideas of evolution with new ideas principally Mendelian genetics.
The Modern Synthesis also integrated other fields such as palaeontology.
The modern synthesis includes much of the evolutionary theory we now use in practice.
E.g. The Hardy-Weinberg equation: using gene frequencies to tell if evolution is occurring in a population.
Key figures in the Modern Synthesis included Fisher, Haldane, Dobzhansky, Wright, Ford and others.
Sensory Physiology Lecture: Diversity of Sensory Systems summary
Sensing the environment is essential for many aspects of the lives of animals
The most common sensory systems are; mechanical, visual, auditory or olfactory/gustatory
Sensing has a physiological basis, encoded in genes, and usually requires (or leads to) specific behaviours
Simple stimuli can underpin complex interactions
What is behaviour?
A behaviour is an action carried out by muscles under the control of the nervous system
All of animal physiology contributes to behaviour, and behaviour influences all physiology
The ability to sense and react evolved billions of years ago in prokaryotes
Often, reactions are to environmental stimuli
Enhanced survival and reproductive fitness
Simple recognition and reponse circuits led, ultimately, to complex nervous systems and behaviours – like choosing to study at the University of Essex!!
What are synapses?
Synapses are junctions between neurons and other cells
Most synapses are chemical synapses
When an action potential depolarises the plasma membrane at the synapse, calcium channels open
The increasing intracellular Ca2+ level causes the release of neurotransmitter
The neurotransmitter binds to a receptor on the postsynaptic cell
Sensory Physiology Lecture: From Sensors to Animal Behaviour summary
Behaviour requires animals to sense their environment
Stimuli and responses are diverse, but signal detection and transmission always happen the same way
Sensory neurons transmit electrical signals by ion transport across membranes
Neurons form nerves that form nervous systems
Complex organisms complex nervous systems complex (learned) behaviours
What stimulus will “unblock” or trigger a behaviour?
Tinbergen kept three-spined sticklebacks (Gasterosteus aculeatus)
Males are very territorial and will attack other males
Male fish do not attack female fish
Hypothesis: red colouration is the stimulus for aggression (proximate cause)
Territorial response is a “Fixed Action Pattern”
Sequence of unlearned acts linked to stimulus
Once initiated, continue until completed
Trigger is external, is called a “Sign Stimulus”
Notes on behaviour?
Psychological systems and processes
Carried out by muscles under nerve control
Behaviour can be for reproduction, defence, foraging
For homeostasis, adjusting conditions
Feedback from and to Physiology
Learning and imprinting notes.
Learning is “modification of behaviour as a result of experiences”
Learning capacity is dependent on nervous system organisation
Learning is formation of memories = changes in neural connections
Challenge to explore how nature (genes) and nurture (environment) combine for learning
In many species, bonding with others is important for survival
In infants – imprinting to others occurs only during the “sensitive period”
In Gulls – 1-2 day period of mutual imprinting of parent to offspring and offspring to parent
Tinbergen’s four questions?
What is the stimulus, what is the physiological mechanism that mediates response?
How does experience/development mediate response?
How does behaviour aid survival & reproduction
What is the evolutionary history of behaviour?
Behavioural Ecology Lecture: Mating Systems & Kin Selection summary 1
- Different forms of learning
- Behaviour can be modified by learning, development, physiology
- Sensitive periods
- Behaviour can evolve through optimality; i.e. decision making evolves
- Behaviour can be passed on by learning, as well as being genetically inherited
- Sometimes a single allele – sometimes more complex
Behavioural Ecology Lecture: Mating Systems & Kin Selection
Competition for access to mates and successful reproduction drives sexual selection (inc. sexual conflict later in course).
Parental care and certainty of paternity drives mating system structure
Many mate choice systems promote pre- (leks and female choice; male territory fighting), during (mallard mating flights) or post- copulatory (multiple mating and sperm competition) competition between males
Competition can lead to selection for variant advantage – frequency dependent selection – leads to a game (e.g. Game Theory)
Male polymorphisms can arise - rare phenotype advantage can occur
What are the 3 main mating systems?
Three general mating systems, all involving innate as opposed to learned behaviors, are seen in animal populations: monogamous (monogamy), polygynous (polygyny), and polyandrous (polyandry). In monogamous systems, one male and one female are paired for at least one breeding season.
What is Altruism?
Natural selection favours behavior that maximizes an individual’s survival and reproduction
These behaviors are (often) selfish
Some animals behave in ways that reduce their individual fitness but (appear to) increase the fitness of others
This kind of behavior is called altruism
Different types of fitness.
Direct fitness is fitness gained through personal reproduction
Indirect fitness is fitness achieved by helping
nondescendant kin survive and reproduce
The evolution of altruistic behavior can be explained by inclusive fitness
Inclusive fitness is the total effect an individual has on proliferating its genes by producing offspring and helping close relatives produce offspring
What is Reciprocal Altruism?
Altruistic behavior toward unrelated individuals can be adaptive if the aided individual returns the favor in the future
This type of altruism is called reciprocal altruism
Reciprocal altruism is limited to species with stable social groups where individuals meet repeatedly and cheaters (who don’t reciprocate) are punished
This strategy has the following rules
- Individuals always cooperate on first encounter
- An individual treats another the same way it was
treated the last time they met
- That is, individuals will always cooperate, unless their opponent cheated them the last time they met
What are the costs of living in a group?
Intragroup hierarchy – competition for food – remember ideal free distributions!
Lost mating opportunities – competition
Increased detection
Paternal certainty
Brood parasitism
Parasitism & disease transmission
Rarely, spiteful behaviour
What are the Benefits of Living in Groups?
Shared responsibilities – foraging more successful
Inclusive fitness – reduced cost
Finding a mate
Protection
Other fitness benefits
What is Ecology?
The scientific study of the interactions between organisms and their environment that determines the distribution and abundance of organisms
What is organismal ecology?
Organismal ecology studies how an organism’s structure, physiology, and (for animals) behavior meet environmental challenges
