Week 29 Flashcards
Define and describe the term biodiversity
Definition: The variety of life at all levels of biological organization, including genetic, species, functional, and ecosystem diversity.
Description: Encompasses the richness and variability of life forms and ecological complexes they inhabit.
Define and describe scales of biological organization
Scales:
Organisms → Populations → Communities → Ecosystems → Biosphere.
Description: Hierarchical levels from individual life forms to global ecological systems.
Define and describe 4 different types of biodiversity
Genetic Diversity : Genetic variation is a measure of the genetic differences that exist within a population. The genetic variation of an entire
species is often called genetic diversity.
Species diversity : Species diversity is a combination of two
measures:
1. The number of species in a given area. This is
called species richness. We call it N (N = number)
2. The abundance of each species in a given area.
Abundance is measured relative to the other
species, so this is called the relative abundance
of species.
3. Diversity can be calculated mathematically in
different ways, but always combines the two
such that each are taken into account.
Functional diversity : Functional diversity is a measure of biodiversity that generally
concerns the range of things that organisms do in communities and ecosystems. Functions keep an ecosystem running!
Ecosystem diversity : : Variation in ecosystems, including different community structures and environmental conditions.
Identify the scale at which different types of biodiversity exists
Genetic Diversity exists at the species and population levels.
Species Diversity is measured at the community level.
Functional Diversity occurs at the community and ecosystem levels.
Ecosystem Diversity is observed at the biome and biosphere levels.
Explain why different types of biodiversity are important to consider
Genetic Diversity ensures adaptability and resilience to environmental changes.
Species Diversity maintains ecosystem stability and interactions.
Functional Diversity supports essential ecosystem processes (e.g., nutrient cycling, pollination).
Ecosystem Diversity provides a range of habitats and conditions for various species to thrive.
Provide evidence that humans are part of the great ape evolutionary lineage, and name our closest living relatives
Evidence:
98.8% genetic similarity to chimpanzees/bonobos (closest relatives).
Shared anatomical traits (e.g., opposable thumbs, lack of tails).
Closest relatives: Chimpanzees (Pan troglodytes) and bonobos (Pan paniscus).
List some of the key evolutionary stages and species of hominid evolution
Early Hominins: Sahelanthropus tchadensis (~7 mya).
Australopithecus: A. afarensis (e.g., “Lucy,” ~3.2 mya).
Homo genus: H. habilis (tool use), H. erectus (migration), H. sapiens (~300 kya).
Define the difference between hominids and hominins
Hominids: all members of the great ape clade,
including gorillas, orangutans, , chimps,
bonobos, and humans.
Hominins: the “human” branch of the great
ape clade, including Homo sapiens and our
extinct relatives, such as Australopithicus and
Ardipithicus
Explain how climate change may have played a key role in human evolution
Impact:
Drier, variable climates in Africa reduced forests, favoring savannas.
Selected for bipedalism (efficient long-distance travel) and diet flexibility (more meat).
Define some of the key traits that set hominins apart from other animals, and describe how and when these adaptations arose
Bipedalism: Evolved ~4–6 mya (e.g., Ardipithecus).
Large brains: Expanded in Homo (~2 mya).
Tool use: H. habilis (~2.4 mya).
Reduced sexual dimorphism: Less size difference between sexes vs. other apes.
- Provide general time estimates for the first and second waves of hominin ancestors out of Africa.
First wave: ~1.8 million years ago (Homo erectus).
Second wave: ~60,000–70,000 years ago (Homo sapiens).
Evidence: Fossil distribution maps and migration timelines (Pages 23–24, 34).
Hominids
All members of the great ape clade, including gorillas, orangutangs, chimps, bonobos and humans
Hominins
The “human” branch of the great ape clade, including Homo sapiens and our extinct relatives such as Australopithicus and Ardipithicus.
- Summarize some of the general features, habitats, and adaptations of different Homo species.
Homo erectus: Tall/slender; first to leave Africa; used Acheulean tools (Pages 22, 25).
H. floresiensis: 1m tall, small brain (417 cc); island adaptation (Page 26).
H. heidelbergensis: 1200 cc brain; hunted large game; ancestor to Neanderthals (Page 27).
Neanderthals: Muscular, cold-adapted; advanced tools/jewelry; buried dead (Pages 29–31).
Denisovans: Asian range; adapted to high altitude; interbred with H. sapiens (Pages 32–33).
- Explain the significance of mitochondrial Eve.
Definition: The matrilineal most recent common ancestor (MRCA) of all living humans.
Significance: Lived ~200,000 years ago in Africa; traces via mitochondrial DNA (inherited only from mothers) (Pages 35–36).
- Broadly describe how Homo sapiens migrated out of Africa and met other species of humans.
Migrated ~60,000–70,000 years ago into Asia/Europe.
Interbred with:
Neanderthals (Europe/Asia) (Page 37).
Denisovans (Asia) (Page 33).
Evidence: DNA traces in modern humans (Pages 37–38).
- Why did the Neanderthals go extinct?
Hypotheses:
Competition with H. sapiens for resources.
Disease transmission.
Small population issues (inbreeding, genetic drift) (Page 39)
Tool use in chimps
- Chimps use objects in their environment as tools.
- Chimpanzees modify objects in order to make them
more effective tools. - Tool use varies from one population of chimps to
another–in other words, chimps exhibit variations in
culture. - Chimps learn by observation and practice how to make
and use tools–in part, they learn by imitation. - Chimps have been observed hunting small mammals,
“bush babies” with spears!
what is oldowan
Hominins developed a style of toolmaking called Oldowan. The
shapes of the tools show how they were made, by striking off
flakes from large, round rocks.
Hominins used tools to scavenge meat and possibly to fashion wooden tools
Acheulean Technology
- New elaborate
toolmaking - Hand axes
- Fashioned using
teardrop-shaped
rocks - Marked major
transition in brain
function - Delicate control of
hands - More detailed
planning - Still continued to use
Oldowan tools also
Homo heidelbergensis
Diverged from H. erectus 600,000 years ago
* Larger brain at 1200 cc
* Expanded out of Africa to Asia and Europe
* Hunted with wooden spears and butchered rhinos and
other large animals
* Ice Age brought
adaptations to Europeans
* Stubby legs
* Wider chest
* More muscular bodies
* Ancestors of Neanderthals
Neanderthals
Large brains at least as big as
ours
Meat diet
Hunters
Advanced tools
Wore jewelry! Colored and
drilled holes into shells
Vanish from fossil record 28,000
years ago
denisoviansranged across which contenint
asia
Who was Mitochondrial Eve?
She lived about 200,00 years ago.
* She lived in Makgadikgadi, a vast wetland in what is now the Kalahari Desert.
* L0 shows the populations with the most ancestral MtDNA.
As Homo sapiens moved across the continents, they interbred with both …….. and ……
Neandarthal and Denisovans
Why did the Neanderthals go extinct?
It’s not really known!
* Neanderthals went extinct within a few thousand years
of Homo sapiens’ arrival in Europe and Asia, suggesting
that the interaction played a role…
* Competition for food?
* Disease?
* …Or maybe just small
population problems!
* Inbreeding
* Genetic Drift
* Random mortality
Chimps and bonobos
Chimps – Pan troglodytes
* Patriarchal (male dominated)
communities
* Smaller groups
* Alpha male controlled
* Resolve conflict through
aggression.
* More sexual dimorphism
(males larger)
* More tool use in the wild
* Specific territories,
aggressively patrolled,
neighbours avoided.
Bonobos – Pan paniscus
* Matriarchal (femaledominated)
* Larger groups
* Females have social bonds
and exert social dominance
over males.
* Resolve conflict through
sexual behaviour.
* Little sexual dimorphism
* Less tool use in the wild.
* Territorial, but territories
overlap and mating occurs
between groups.
As the climate became more variable, and
cooler overall, hominids may have had to
develop new adaptations to:
1) Less forest
2) Moving large
distances.
3) Eating more meat
Who are the first branch of hominins
Ardipithicus
