Evolution Overview & Human Placing in Nature

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Questions and Answers

What is a characteristic of microevolution?

It is a process solely driven by environmental changes.

It results in changes within a population over generations. (correct)

It results in the formation of new species.

It is irreversible and always leads to beneficial traits.

What is natural selection acting on?

Species as a whole

Individuals within a population (correct)

Random mutations in DNA

Environmental factors only

Which type of natural selection is characterized by the selection of one extreme trait?

Stabilizing selection

Disruptive selection

Directional selection (correct)

Neutral selection

What could be a result of stabilizing selection?

Uniformity of traits in a population Signup and view all the answers

In what scenario would disruptive selection likely occur?

When both extreme traits are favored Signup and view all the answers

What is true about the randomness of mutations in natural selection?

Mutations play a random role in creating variation. Signup and view all the answers

What is a common perception about the fossil record in relation to evolution?

It is sometimes seen to have too many gaps. Signup and view all the answers

What is the ecological outcome of natural selection based on variations?

It leads to the creation of favorable, neutral, or harmful changes. Signup and view all the answers

What is the main purpose of a life table in studying demographics?

To follow a cohort of individuals and calculate age-specific mortality Signup and view all the answers

Which type of survivorship curve represents species with high mortality rates in early life stages?

Type III Signup and view all the answers

What does the symbol 'r' represent in population growth calculations?

The intrinsic rate of increase per capita Signup and view all the answers

In a population defined as 'closed', which of the following factors is absent?

Emigration Signup and view all the answers

What is represented by 'ΔN/Δt' in population dynamics?

Change in population size over time Signup and view all the answers

Which of the following factors contribute to changes in population size?

Births, deaths, immigration, and emigration Signup and view all the answers

What does the symbol 'lx' in a life table signify?

Probability of surviving to any given age Signup and view all the answers

Which of the following best describes type II survivorship curves?

Mortality is constant regardless of age Signup and view all the answers

What morphological changes were observed in guppies from pools without predatory C.alta?

More and larger spots, and increased body size Signup and view all the answers

How did the presence of C.alta affect the guppy's coloration and body size?

Decreased coloration intensity and smaller body size Signup and view all the answers

In Endler's greenhouse pool experiments, how did guppy spot size vary with sediment particle size in the absence of predators?

Spots decreased with smaller particles Signup and view all the answers

What was the primary reason for the differences in reproductive strategies between low-predation and high-predation guppies?

Age at sexual maturity and reproductive investment Signup and view all the answers

Which opsin types are expressed at high levels in the eyes of low-predation female guppies, allowing them to detect red/orange coloration?

2 of the 9 types of opsin Signup and view all the answers

What effect did translocation to a guppy-free environment have on maturation and reproductive investment over a period of four years?

Maturation was delayed and reproductive investment decreased Signup and view all the answers

Which of the following statements accurately describes the Order Primates?

Comprises 16 families and over 230 species Signup and view all the answers

What is a notable characteristic of mouse lemurs?

They are nocturnal Signup and view all the answers

What is one reason male water bugs might engage in parental care?

To attract additional females Signup and view all the answers

What was a significant finding in the study of Great tits regarding brood sizes?

Reduced broods produced adults that rarely had a second brood Signup and view all the answers

How does chick color influence parental care in coots?

It indicates the likelihood of survival Signup and view all the answers

Why do male water bugs require oxygenation for their eggs?

Their larger size necessitates more oxygen for development Signup and view all the answers

What is a potential benefit of leaving a baby in a creche for Mexican free-tailed bats?

Improved thermoregulation for the babies Signup and view all the answers

What factor affects adult birds with enlarged broods in terms of future breeding?

Weight of fledglings Signup and view all the answers

What do Cliff swallows benefit from in their large colonies?

Increased variation in young's vocal calls Signup and view all the answers

What potential disadvantage might females face in parental care compared to males?

Higher costs related to fecundity Signup and view all the answers

What percentage of insect species richness in rainforest canopies is represented by beetles?

40% Signup and view all the answers

How many estimated specialist insect species are associated with Luehea seemannii across all tropical trees?

30.4 million species Signup and view all the answers

Which of the following best describes the current rate of species loss in comparison to pre-human rates?

Over 10,000 times faster Signup and view all the answers

What is a stated reason for why we should care about biodiversity?

The loss of genetic information is irreversible Signup and view all the answers

What proportion of land that could support tropical rainforest has been lost?

40% Signup and view all the answers

How many species are described on average per year?

18,000 species Signup and view all the answers

What is the estimated total number of species on Earth, according to the estimates mentioned?

8-10 million species Signup and view all the answers

What is a potential benefit of preserving biodiversity in terms of genetic resources?

Pharmacological use and biotechnologies Signup and view all the answers

What is the optimal behavior for a consumer when the most valuable prey is encountered infrequently?

Expand the range of preys to include the next most valuable type Signup and view all the answers

Which factor does NOT influence the time an individual should stay in a resource patch according to the marginal value theorem?

A consumer's energy needs Signup and view all the answers

What strategy should animals in unproductive environments typically adopt?

Be generalists and broaden their diet Signup and view all the answers

What happens to the rate of energy gain as resources in a food patch deplete?

It decreases Signup and view all the answers

What criterion is most important in determining when to leave a food patch?

The cumulative energy gain relative to time spent Signup and view all the answers

In a landscape where highly valuable patches exist, what is the primary dilemma a consumer faces?

Determining how long to exploit a high-value patch before leaving Signup and view all the answers

How should a consumer's diet change in relation to the productivity of their environment?

Diets should broaden as productivity declines Signup and view all the answers

What is the purpose of maximizing the net rate of energy gain in consumers?

To ensure survival and reproduction Signup and view all the answers

Study Notes

L1 Overview: Evolution & Placing Human in Nature

Sophisticated knowledge of biophysical environments isn't restricted to science.
Homo sapiens lived as hunter-gatherers.
Aristotle believed populations remained stable except for occasional plagues; nature maintained a balance.
Aristotle ordered organisms in a linear sequence, humans at the top.
Christians believed species were created by an intelligent designer, and the world is eternal and unchanging.
Archbishop James Ussher (1650) proposed a young Earth.
George Louis Leclerc Comte de Buffon was a father of evolution and natural history, and questioned the young Earth idea.
Georges Cuvier noted fossils resembled modern species but many past species were extinct.
Mary Anning discovered extinct marine reptiles.
Thomas Malthus's idea of exponential population growth vs. arithmetic growth of resources suggested instability in nature.
The Diluvial Theory / Catastrophism: fossils represent animals that perished in the biblical flood.
James Hutton's Uniformitarianism proposed the Earth's landscapes were formed by the same natural processes acting slowly over a long time.
The Earth is very, very old.

L2 The Scientific Approach 1: How do ecologists investigate problems?

Science involves investigating and asking questions about the world.
Key historical methods: observational astronomy (Galileo), rationalism (Descartes), reductionism, empiricism (Bacon).
Hypothesis testing is essential in science, needing repeatable experiments.
Proximate causes explain how something works, while ultimate causes explain why.
Four main types of ecological investigation: description and observation, hypotheses, predictions, and experimental testing.
Management involves applying understanding to influence original patterns.
Proper experimental design, including appropriate sample size and accounting for confounding variables, are crucial for repeatable and trustworthy results.

L3 The Scientific Approach 2: Doing Ecological Experiments

Setting up null and alternative hypotheses.
Importance of sampling methods, including systematic and random sampling.
The 'rules of 10' (e.g., 10 replicates for each variable) in sampling.
Alpha and beta diversity.
Methods to determine competition: comparisons of species distributions, identifying common species, demonstrating resource limitations, and manipulating population sizes.
Bias in ecological research – positive results, novelty, are more likely to be published than negative ones; taxonomy biases exist.
Important to consider the generality and limitations of experimental results.
Considerations for good experimental design: matching the questions to the scope of the research, ensuring samples are large enough and replication thorough, and appropriately interpreting the results.

L4 The Scientific Approach 3: How do we deal with environmental complexity?

Experiments for investigating ecological problems: mensurative, observational; manipulative, formal procedure.
Manipulative experiments compare treatments with a control group.
Types of experiments include laboratory (LE), field (FE), and natural experiments (NE).
Factors influencing the choice of experiments: control of variables, scope and scale, number of species, ease, and cost.
Dealing with environmental complexity, especially conflicting explanations.
Strong inference methods.
Proper experiment design and replication essential for trustworthy conclusions.

L5 What is evolution by natural selection?

Evolution is the accumulation of changes in organisms' characteristics over generations.
Darwin's theory of evolution by natural selection hinges on variation, heredity, and limited resources leading to competition; individuals with advantageous traits have more offspring.
Necessary conditions: variation, heritability, influence of the environment on survival and reproduction.
Time available for evolution: Earth's age, earliest fossils, and the evolution of Homo sapiens.
Macroevolution: large-scale changes over a long time, including speciation.
Types of Speciation: allopatric, peripatric, parapatric, sympatric.

L6 What are the ecological outcomes of natural selection?

Evolution is a 2-stage process involving mutation, which creates variation; natural selection determines which variations are passed to future generations.
Fitness is the relative contribution an individual makes to future generations.
Adaptive strategies can be: directional, stabilizing, disruptive.
Sexual Selection: competition between individuals (typically males) for mates, leading to traits that attract mates.
Inclusive fitness: individual's total evolutionary success considering both direct reproduction and the impact on reproduction of close relatives.

L7 What is biodiversity & why is it important?

Biodiversity refers to biological diversity - variety of life.
Often measured at the species level.
Anthropocene epoch includes factors of habitat degradation, biological invasions, pollution, overexploitation that lead to biodiversity decline.
Science tries to understand biodiversity and its effects.
Patterns differ across latitudes, among habitats & ecological levels, within and among taxa, also across habitats and ecosystems.
Species richness may vary significantly in different ecosystems.
Global decline of biodiversity.

L8 How do adaptations evolve?

Genes code for phenotypes, which interact with the environment to influence the survival and reproduction of individuals.
Natural selection acts on individuals (phenotypes), but genes are selected because of the effect on the phenotype; Genes and phenotypic expression directly link and are influenced by environmental interactions.
Fitness is the proportionate contribution of an individual to future generations and is directly linked to adaptation.
Adaptation is any feature helping an organism survive and reproduce in its environment.
Adaptations can be classified as structural, behavioral, or physiological.
Examples are given of each type of adaptation.

L9 Species Interaction

In community ecology, species interact, forming food webs.
Trophic level describes an organism's position in a food web.
Ecological role is a species functional role in an ecosystem.
Niche describes conditions needed for species existence and the role it plays.
Fundamental niche represents possible environment, while realized niche is the actual environment.
"Pyramid of numbers" depicts relative numbers of individuals in each trophic level; “Pyramid of Biomass” depicts the biomass; “Pyramid of Energy” depicts energy flow.
Predation involves predator consuming prey.
Herbivory involves an organism consuming plants or plant parts, usually not resulting in plant death.
Parasitism involves one species (parasite) consuming part of the host, which may or may not result in host death.
Competition occurs when two species require the same resources, leading to fitness reduction for one or both species.
Exploitation competition: competitors share resources.
Interference competition: species restrict access through direct interaction.
Species can exploit resources differently – "resource partitioning."
Mutualism, commensalism.

L10 The mating game: conflict or cooperation between the sexes?

Monogamy: relationship where one male and one female form a pair bond.
Polygamy: male or female has more than one mate; Polygyny: one male with many females Polyandry: one female with many males
Reproductive success in animals often relies on the number and quality of mates.
Female reproductive success often is limited by resources, while males often are limited by access to females (mate availability).
Implications of varying sex ratios are discussed, and their relation to variation in population fitness.
Consequences of differing sex ratios, including the Trivers-Willard effect, local mate competition, and resource enhancement, are analyzed.

L11 Is insect colouration a defensive adaptation?

The life-dinner principle describes the selective pressure on prey (escape) and predator to maximize their fitness (consume more prey or survive longer).
Two common approaches for predator-prey coexistence: top-down (predators controlling prey numbers) and bottom-up (resources controlling prey population numbers).
Protective adaptations are against physical, chemical, and other dangerous factors, and typically involve traits that help species survive in their environment.
Defensive adaptations describe the ways organisms protect themselves from attacks by other organisms (usually predators).
Protective strategies include crypsis (camouflage) and aposematism (bright colors warning of noxiousness).
Coevolution, coevolutionary interactions are described between predator and prey.
Defensive arsenal of prey – crypsis, mimicry, and aposematism.

L12 Optimal foraging: What to eat, where, when and how?

Foraging: Exploitation of resources; often referring to food resources.
Foraging Modes: sit-and-wait (ambush), active.
Determining optimal foraging strategies: factors to consider: spatial/temporal patterns in resource availability, quality of different resources (net energy gain), and cost of obtaining those resources.
Optimal Foraging Theory explains that organisms should make the most efficient use of their time foraging.
Foragers should maximize energy gain per unit of time; the costs of getting a resource need to be considered.

L13 What prevents populations from growing indefinitely?

Populations consist of members of the same species and share environment and resources.
Limits to population growth are influenced by both intrinsic factors (those internal to a population, such as competition and density-dependent mortality) as well as extrinsic ones (external to a population, such as climate change & catastrophes).
Density-independent factors (DIF): influence mortality without dependence on population density; factors like climate change and catastrophes affect all members equally.
Density-dependent factors (DDF): influence mortality with dependence on population density.

L14 Why do some animals live in groups?

Animals live in groups for various reasons from safety and survival, to mate selection and breeding success.
In addition to benefits such as safety and resource increase, there is also competition involved in group living.
Natural selection shapes behaviours that benefit the donor, in conjunction with other factors such as competition & resource availability.
Groups are often safer from predation due to the dilution effect.
Groups also facilitate cooperative behaviours like cooperative hunting.

L15 Brilliant bats, and examples of co-evolution

Predators and prey, in this case bats and moths, are in a constant selection pressure to adapt to survive their relationships.
Sensory adaptations (hearing and echolocation in bats, tympanic ears for hearing ultrasound in moths).
Behavioral strategies for predator avoidance (escape, distraction, confusing the predator), some insects have evolved ultrasound generating abilities, like some moths.
Co-evolution: moths have developed defenses like camouflage, and aposematism against predation by bats, and both parties have evolved to adapt to environmental changes; Some insects can mimic their environment effectively or adopt visual, audial, thermal cues of color or physical attributes to gain protection from predators.

L16 The Evolution of sex ratios

Anisogamy involves the production of gametes of different sizes (typically eggs are large and sperm are small); this difference in gamete size influences the sex ratio evolutionarily.
Females are often ‘limiting resource’ for males in relation to mating.
Fisher's principle suggest that a population with a 1:1 sex ratio will be more successful than one with a skewed sex ratio.
Implications of sex allocation, and its importance for species' fitness, are described, with examples.

L17 Case study 2: How (or why) did the guppy get its spots?

Guppies (Poecilia reticulata) show great diversity in colour and spot patterns; variation in colours may occur due to environmental conditions or predation, particularly in low-risk environments.
Live-bearing, giving rise to significant reproductive potential and populations fluctuating in size rapidly.
Guppies show an example of natural selection and sexual selection interacting (to respond to predation and attract mates).
Endler's experiments (controlled pool experiments and field transplants) confirmed that natural selection can strongly influence species adaptation (traits), depending on environmental conditions.

L18 Human Evolution: where did we come from?

Primates have 2 suborders: Prosimii & Anthropoidea.
Key primate characteristics: heterodont dentition (differentiated teeth), presence of five digits, and grasping hands (flexible).
Primates' adaptations for life in trees (arboreal life) are discussed.
Evolutionary history of primates, including humans, is complex and nonlinear.
Hominins evolved and diversified over millions of years; fossil evidence suggests an important role for bipedalism (walking on two legs).
Some key species like Australopithecus are discussed; characteristics, adaptations, and environment is presented.
Homo species, including Homo habilis, Homo erectus, to Homo Neanderthalensis and Homo sapiens are highlighted as crucial evolutionary steps.

L19 Human Evolution: Meet the relatives

Scarcity of fossils makes it difficult to decipher human evolution completely, including complications of age ranges.
The Piltdown Forgery is an example of a human evolution hoax.
Various proposed human evolutionary relatives and characteristics of each are highlighted.

L20 Anthropocene

The evolution of humans is discussed, along with characteristics such as larger brains and the development of language.
This chapter investigates the possible factors that may lead to the evolution of larger brains for humans, including ecological challenges of food-finding and social or ecological pressures.
Cultural evolution, the transmission of knowledge and behaviours across generations, is a hallmark of humans.
The debate around anthropocene and its importance and causes in relation to species extinction and climate change are covered.

L21

Global increase in environmental temperatures and its negative impacts on several environmental aspects.

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Description

This quiz covers key concepts in the evolution of Homo sapiens and their place in nature, exploring historical perspectives from Aristotle to Malthus. It examines ideas on population stability, extinction, and the interplay between species and their environments. Test your knowledge on these fundamental theories and figures in biology and natural history.